Electrifying the Ferry Market

The first all-electric ferry built for operations in the United States may soon be coming to fruition in the Pacific Northwest. Bremerton, WA-based Art Anderson Associates with partner EESImarine has been developing concepts for the first all-electric battery-powered vehicle ferry to be produced and used in the United States. This zero emissions ferry will be the first of its kind putting the United States and more specifically, the Puget Sound region, on the map as a leader in green technology in the marine industry.

Art Anderson Associates is at the forefront of green technology within the marine community. Founded in 1957 as a naval architecture and marine engineering firm, the company has grown and diversified to employ architects, naval architects, planners, construction managers and civil, structural, mechanical and electrical engineers to create an interdisciplinary team. Art Anderson Associates has supported local and international ferry systems including Washington State Ferries and Alaska Marine Highway Systems for over 30 years.

New ferry for Guemes Island route
Art Anderson Associates and EESImarine are teaming up to generate funding for the potential implementation of the vehicle ferry concept for Skagit County’s Guemes Island-Anacortes passenger and car ferry replacement.

After an initial review of the Guemes Island Ferry route, Art Anderson Associates proposed to the Skagit County Board of Commissioners the all-electric ferry as a viable replacement for their aging ferry with additional benefits of reducing the lifecycle costs and environmental impacts that a traditional diesel ferry would have. The Skagit County Board of Commissioners signed a resolution on December 29, 2015 directing its Public Works Department to conduct an all-electric ferry propulsion and feasibility study with Art Anderson Associates.

The all-electric ferry being developed will be a practical alternative for operators of ferries throughout the world who want to accomplish zero emissions and achieve a reduction in overall costs of operations. It is projected that the all-electric ferry will reduce owner costs by up to $170,000 per year and will provide an overall breakeven cost after five years of operation when compared to a diesel engine driven vessel.

Two battery banks using low maintenance technology will provide the vessel’s propulsion and power. This clean energy storage uses vanadium flow batteries provided by UniEnergy Technologies (UET) of Mukilteo, WA. This revolutionary battery system combines chemicals in a reduction-oxidation reaction that yields electricity. UET’s batteries are economical, safe, environmentally responsible, and highly reliable. After the batteries have reached the end of their utility, UET handles the decommissioning process and recycles the batteries. This process supports the development of recyclable fuel and eliminates the waste conventional batteries leave at the end of their lifetime.

A key part of the design was building the battery and propulsion system in modular format to permit complete system construction and testing before shipment to the shipyard. “This effectively makes the main power & propulsion system plug-N-play and eliminates a major headache for many small and mid-size yards,” says Payne.

Payne, an expert in electric marine and hybrid propulsion systems, has been designing commercial marine electrical systems since 1993.

The electric ferry also demonstrates energy efficiency and energy conservation. With electric motors and the vanadium flow batteries, the propulsion system’s efficiency is approximately 73%, which is twice the efficiency of a traditional diesel-driven vessel. In addition, the electric ferry supports the conservation of energy by obtaining its power from the electric grid—which in Washington is largely supplied by renewable energy sources including solar, biomass, biodiesel, hydroelectric, and wind power.

The cost of energy for powering the ferry is 30-60% less than for the equivalent amount of diesel fuel required for a vessel of a similar size. This estimation can largely vary due to the fluctuation in oil prices but even on the low end offers significant savings both fiscally and environmentally. The electric ferry project also has the ability to further provide savings by supporting demand-side response and management by charging during the evening when the demand for electricity is low.

The vessel and power system design requires no exotic hull materials and can also be used to retrofit an existing vessel. New all-electric vessel construction costs are estimated at approximately 5% more than an engine-driven version.

“This design concept has the potential to be a true differentiator in the marine industry as an alternative form of vessel propulsion,” stated Eric Engelbrecht, Vice President at Art Anderson Associates. “With demonstrated performance and future advances in battery technology, this propulsion system can be scalable and ultimately contend with other means of propulsion for cost of construction and operation, and have zero environmental impact.”

Seeking Funds
Funding is being sought through a variety of public and private sources. Skagit County has committed funds to conduct a propulsion study on the current ferry route and Art Anderson Associates is developing technical content for further funding outreach.

Currently, Art Anderson Associates is pursuing funding from Washington State’s Clean Energy Fund II, a state funded research, development and demonstration grant for technological advances in clean energy that bolsters the state’s clean tech sector. Funding of the Clean Energy Fund II supports development, demonstration, and deployment of clean energy technologies that save energy and reduce energy costs, reduce harmful air emissions, or otherwise increase energy independence for the state.  

If successful, this project would be the first all-electric, battery-powered vehicle ferry in North America. “We are extremely excited to be working with Art Anderson Associates to conduct a feasibility analysis for this innovative technology that can have so many positive impacts to the citizens of Skagit County, Washington state’s marine industry and the environment,” said Captain Rachel Rowe, Ferry Operations Division Manager for Skagit County.

Benefits of Going All-Electric
The vessel will have zero emissions, which eliminates approximately 650 tons of greenhouse gases annually. This does not include the reduced emissions from the elimination of the transportation and delivery of the 59,000 gallons of diesel utilized by the existing vessel each year.

An all-electric vehicle ferry means direct cost savings to taxpayers and zero-emissions benefits to all environments. This technology will accomplish local, federal and global initiatives to be a zero emission producer and lower our carbon footprint.

  • Uncategorized

The Evolution of the Z-Drive Inland Towboat

 

Birth of the Z-drive
Z-drive propulsion is over 60 years old. The Rudder Propeller, or Z-drive as we know it today, was developed and built in 1950 by Josef Becker, founder of the present-day Schottel Group. But it wasn’t until the 1980’s that its use began in North America, when it was found predominately in ship assist tugs, not inland towboats. Since the early ‘80’s the Z-drive ship assist tug fleet in North America has grown from a handful to almost 300, tripling in the last 15 years. It continues to grow and is the dominant propulsion in newbuild ship assist tugs.

The inland towboat industry has lagged in adopting Z-drive technology, but is now on the precipice of the same exponential growth experienced in the ship assist market. In 2008, two inland companies utilized Z-drive towboats. One was Southern Towing Company out of Memphis, TN, and the other a Pacific Northwest company, Shaver Transportation. Less than a half-dozen Z-drive towboats worked the inland river system. Today, we find 10 companies and well over 50 Z-drive towboats built or under construction—and more to come. What caused the change in 8 years?

The inland towing industry is well-versed in navigating the challenging system of inland rivers and canals. It has expertise in adapting to a river’s changing depth, sand bars, currents, and back eddies, and has developed reliable routes and channels that they have followed for years. However, they also expect periodic dramatic changes—such as when a river cuts a new channel to bypass an established one that has silted in. The same is happening with propulsion technology in the industry. Z-drive technology is the cut bank that has broken through to a new and more efficient pathway towards getting the job done. Two companies were instrumental in carving this new path.

Pioneers
The growing popularity of Z-drives in the inland towing industry today is due in large part to two Z-drive pioneers of the distant and recent past—the towboat Miss Nari, and Southern Towing Company.

The Miss Nari, originally named the Delta Cities, was built as a twin-screw conventional towboat in 1951. The boat burned in 1970 and changed hands several times. Eddie Conrad renovated the newly named Miss Nari with Niigata z-drives and diesel engines, and returned it to service in 1982. It is widely accepted that the Miss Nari was the first U.S. towboat to use Z-drive propulsion on the Mississippi River system.

Bill Stegbauer of Southern Towing Company of Memphis, TN, is the more recent pioneer. In the spring of 2006, he began discussions with Ed Shearer of Shearer & Assoc., Inc., to design a new series of 3,200 hp towboats. Following research and discussion, Stegbauer decided to pursue the possibility of a towboat equipped with Z-drives. The first of eight Southern Towing Z-drive towboats went into service in August 2008.

Many factors that led Southern Towing to Z-drive towboats are the same ones driving the change today. However, Southern Towing was the first to step into the deep end of the pool while others stood on the edge, waiting to see whether the Z-drive concept would sink or swim. A key factor in getting others to follow was the empirical data generated by Southern Towing’s fleet, which had multiple opportunities to make side-by-side performance comparisons between conventional and Z-drive towboats pushing identical tows on identical routes.

Performance
Inland towboats are tasked with maneuvering large tows, running at 80% load 24/7 year round, navigating bends, currents and restricted channels, meeting other vessels in close quarters and transiting narrow bridges and locks. Key performance criteria for an inland towboat are its amount of thrust, steering power and maneuverability. Z-drive propulsion has inherent advantages over conventional propulsion in all of these categories. It has a high ratio of converting horsepower to thrust, 50% more backing (astern thrust) power, 50-70% more steering force and, of course, 360° thrust capability.

The advantageous Z-drive thrust and steering performance translate into more efficient and safer operations in most inland towing applications. A critical factor to a towboat’s maneuvering success is its ability to “hold the stern” or “not lose the stern.” That concept is extremely important to a towboat pilot. Whether he or she is going into a lock, making a bridge, or going around a bend, his or her fate rests largely on the ability to control the stern of the towboat, its location in the river, its aspect to the current, and its rate of swing and advance.

Making a bend while heading downstream is an everyday occurrence on the rivers. Flanking and driving a bend are two common techniques used to navigate a bend. Both maneuvers require the pilot to position the stern of the towboat so that the pilot can overcome the tendency of the current to sweep the tow down on the outside of the turn. In the case of driving the bend, the pilot has to have enough steering power to swing the tow and power out of the bend before the towboat ends up on the outside bank. In the case of flanking, the pilot holds the stern more or less stationary over the ground while the current pushes the head end of the tow around. Flanking requires long periods of time and large amounts of power to navigate through relatively short stretches of the river. This is less efficient and uses more fuel but is required if the towboat doesn’t have enough power and maneuverability to drive the bend. A Z-drive towboat with its superior omni-directional thrust may be able to drive the bend in cases where a conventionally propelled towboat would have to flank.

This is one example of Z-drive performance manifesting as operational efficiency in comparison to conventionally propelled towboats. A Z-drive more efficiently transfers main engine horsepower and applies that horsepower to inland towing applications. Put simply, it can do more with less. A Z-drive towboat consumes 20-30% less fuel, has shorter transit times, covers more distance per gallon and pushes a greater number of barges than a conventional towboat of similar horsepower.

Skepticism
The question remains: If Z-drives are so great what took so long? Skepticism to new technology is part of the DNA of the towing industry. And for good reason. The life cycle of a towboat can be 40 to 50 years, requires a large capital outlay and may not produce a return on investment for 5-10 years. You don’t want to make a bad bet that you must live with for 50 years. Questions of initial cost, reliability and maintenance have always been associated with the introduction of new technology, and Z-drives were no exception. What change agents overcame this skepticism? Although performance advantages of Z-drive propulsion are well documented, economic factors were the final push to get the inland towboat industry to accept Z-drive propulsion.

Economic Change Agents
There are five economic change agents:

  • Empirical Performance Data
  • Fleet Modernization
  • Z-drive Construction Cost Parity
  • Critical Mass
  • Competitive Standard

 Empirical Performance Data
The favorable empirical data generated by Southern Towing provided the “real” towboat data proving that the advantages of Z-drive propulsion are not just theoretical; they are a real.

Fleet Modernization
The inland fleet is in the midst of modernization. Much of the existing fleet is at or near the end of its life-cycle and needs to be replaced. Companies are faced with making large capital investments in equipment. Z-drive propulsion must be evaluated in constructing a towboat today that will remain competitive over the next 30 to 50 years.

Z-drive Construction Cost Parity
The difference in construction costs between conventional and Z-drive propelled towboats turns out to be negligible. It was once thought that Z-drives were more expensive to construct. This assumption was based on the price of Z-drive units. However, it has become apparent that the elimination of reduction gears, shafting, rudders and steering systems negate a large portion of the cost difference. There are also maintenance costs that are reduced or eliminated by removing some of the major mechanical components of a conventionally propelled towboat.

Critical Mass
The fact that there are now 50 or more Z-drive towboats in operation and under construction and more on the way has created a critical mass—whereas at one point a Z-drive towboat was a novelty, it is quickly becoming the norm.

The inland towing industry has gone through many major changes. Just two of them are the transition from steam to diesel and paddlewheel to propeller. These changes have increased efficiency, reduced fuel costs and made the industry safer. Clearly, the use of Z-drive propulsion is another such evolution. While it may not be appropriate for all inland towing applications, what was once a unique and rarely used technology is rapidly becoming an industry standard. Towboat companies positioning themselves for the future will be drawn to Z-drive propulsion. Like the rivers they transit every day, the path of the inland towing industry has cut a new channel.

  • Uncategorized

The Evolution of the Z-Drive Inland Towboat

 

Birth of the Z-drive
Z-drive propulsion is over 60 years old. The Rudder Propeller, or Z-drive as we know it today, was developed and built in 1950 by Josef Becker, founder of the present-day Schottel Group. But it wasn’t until the 1980’s that its use began in North America, when it was found predominately in ship assist tugs, not inland towboats. Since the early ‘80’s the Z-drive ship assist tug fleet in North America has grown from a handful to almost 300, tripling in the last 15 years. It continues to grow and is the dominant propulsion in newbuild ship assist tugs.

The inland towboat industry has lagged in adopting Z-drive technology, but is now on the precipice of the same exponential growth experienced in the ship assist market. In 2008, two inland companies utilized Z-drive towboats. One was Southern Towing Company out of Memphis, TN, and the other a Pacific Northwest company, Shaver Transportation. Less than a half-dozen Z-drive towboats worked the inland river system. Today, we find 10 companies and well over 50 Z-drive towboats built or under construction—and more to come. What caused the change in 8 years?

The inland towing industry is well-versed in navigating the challenging system of inland rivers and canals. It has expertise in adapting to a river’s changing depth, sand bars, currents, and back eddies, and has developed reliable routes and channels that they have followed for years. However, they also expect periodic dramatic changes—such as when a river cuts a new channel to bypass an established one that has silted in. The same is happening with propulsion technology in the industry. Z-drive technology is the cut bank that has broken through to a new and more efficient pathway towards getting the job done. Two companies were instrumental in carving this new path.

Pioneers
The growing popularity of Z-drives in the inland towing industry today is due in large part to two Z-drive pioneers of the distant and recent past—the towboat Miss Nari, and Southern Towing Company.

The Miss Nari, originally named the Delta Cities, was built as a twin-screw conventional towboat in 1951. The boat burned in 1970 and changed hands several times. Eddie Conrad renovated the newly named Miss Nari with Niigata z-drives and diesel engines, and returned it to service in 1982. It is widely accepted that the Miss Nari was the first U.S. towboat to use Z-drive propulsion on the Mississippi River system.

Bill Stegbauer of Southern Towing Company of Memphis, TN, is the more recent pioneer. In the spring of 2006, he began discussions with Ed Shearer of Shearer & Assoc., Inc., to design a new series of 3,200 hp towboats. Following research and discussion, Stegbauer decided to pursue the possibility of a towboat equipped with Z-drives. The first of eight Southern Towing Z-drive towboats went into service in August 2008.

Many factors that led Southern Towing to Z-drive towboats are the same ones driving the change today. However, Southern Towing was the first to step into the deep end of the pool while others stood on the edge, waiting to see whether the Z-drive concept would sink or swim. A key factor in getting others to follow was the empirical data generated by Southern Towing’s fleet, which had multiple opportunities to make side-by-side performance comparisons between conventional and Z-drive towboats pushing identical tows on identical routes.

Performance
Inland towboats are tasked with maneuvering large tows, running at 80% load 24/7 year round, navigating bends, currents and restricted channels, meeting other vessels in close quarters and transiting narrow bridges and locks. Key performance criteria for an inland towboat are its amount of thrust, steering power and maneuverability. Z-drive propulsion has inherent advantages over conventional propulsion in all of these categories. It has a high ratio of converting horsepower to thrust, 50% more backing (astern thrust) power, 50-70% more steering force and, of course, 360° thrust capability.

The advantageous Z-drive thrust and steering performance translate into more efficient and safer operations in most inland towing applications. A critical factor to a towboat’s maneuvering success is its ability to “hold the stern” or “not lose the stern.” That concept is extremely important to a towboat pilot. Whether he or she is going into a lock, making a bridge, or going around a bend, his or her fate rests largely on the ability to control the stern of the towboat, its location in the river, its aspect to the current, and its rate of swing and advance.

Making a bend while heading downstream is an everyday occurrence on the rivers. Flanking and driving a bend are two common techniques used to navigate a bend. Both maneuvers require the pilot to position the stern of the towboat so that the pilot can overcome the tendency of the current to sweep the tow down on the outside of the turn. In the case of driving the bend, the pilot has to have enough steering power to swing the tow and power out of the bend before the towboat ends up on the outside bank. In the case of flanking, the pilot holds the stern more or less stationary over the ground while the current pushes the head end of the tow around. Flanking requires long periods of time and large amounts of power to navigate through relatively short stretches of the river. This is less efficient and uses more fuel but is required if the towboat doesn’t have enough power and maneuverability to drive the bend. A Z-drive towboat with its superior omni-directional thrust may be able to drive the bend in cases where a conventionally propelled towboat would have to flank.

This is one example of Z-drive performance manifesting as operational efficiency in comparison to conventionally propelled towboats. A Z-drive more efficiently transfers main engine horsepower and applies that horsepower to inland towing applications. Put simply, it can do more with less. A Z-drive towboat consumes 20-30% less fuel, has shorter transit times, covers more distance per gallon and pushes a greater number of barges than a conventional towboat of similar horsepower.

Skepticism
The question remains: If Z-drives are so great what took so long? Skepticism to new technology is part of the DNA of the towing industry. And for good reason. The life cycle of a towboat can be 40 to 50 years, requires a large capital outlay and may not produce a return on investment for 5-10 years. You don’t want to make a bad bet that you must live with for 50 years. Questions of initial cost, reliability and maintenance have always been associated with the introduction of new technology, and Z-drives were no exception. What change agents overcame this skepticism? Although performance advantages of Z-drive propulsion are well documented, economic factors were the final push to get the inland towboat industry to accept Z-drive propulsion.

Economic Change Agents
There are five economic change agents:

  • Empirical Performance Data
  • Fleet Modernization
  • Z-drive Construction Cost Parity
  • Critical Mass
  • Competitive Standard

 Empirical Performance Data
The favorable empirical data generated by Southern Towing provided the “real” towboat data proving that the advantages of Z-drive propulsion are not just theoretical; they are a real.

Fleet Modernization
The inland fleet is in the midst of modernization. Much of the existing fleet is at or near the end of its life-cycle and needs to be replaced. Companies are faced with making large capital investments in equipment. Z-drive propulsion must be evaluated in constructing a towboat today that will remain competitive over the next 30 to 50 years.

Z-drive Construction Cost Parity
The difference in construction costs between conventional and Z-drive propelled towboats turns out to be negligible. It was once thought that Z-drives were more expensive to construct. This assumption was based on the price of Z-drive units. However, it has become apparent that the elimination of reduction gears, shafting, rudders and steering systems negate a large portion of the cost difference. There are also maintenance costs that are reduced or eliminated by removing some of the major mechanical components of a conventionally propelled towboat.

Critical Mass
The fact that there are now 50 or more Z-drive towboats in operation and under construction and more on the way has created a critical mass—whereas at one point a Z-drive towboat was a novelty, it is quickly becoming the norm.

The inland towing industry has gone through many major changes. Just two of them are the transition from steam to diesel and paddlewheel to propeller. These changes have increased efficiency, reduced fuel costs and made the industry safer. Clearly, the use of Z-drive propulsion is another such evolution. While it may not be appropriate for all inland towing applications, what was once a unique and rarely used technology is rapidly becoming an industry standard. Towboat companies positioning themselves for the future will be drawn to Z-drive propulsion. Like the rivers they transit every day, the path of the inland towing industry has cut a new channel.

  • Uncategorized

The Evolution of the Z-Drive Inland Towboat

 

Birth of the Z-drive
Z-drive propulsion is over 60 years old. The Rudder Propeller, or Z-drive as we know it today, was developed and built in 1950 by Josef Becker, founder of the present-day Schottel Group. But it wasn’t until the 1980’s that its use began in North America, when it was found predominately in ship assist tugs, not inland towboats. Since the early ‘80’s the Z-drive ship assist tug fleet in North America has grown from a handful to almost 300, tripling in the last 15 years. It continues to grow and is the dominant propulsion in newbuild ship assist tugs.

The inland towboat industry has lagged in adopting Z-drive technology, but is now on the precipice of the same exponential growth experienced in the ship assist market. In 2008, two inland companies utilized Z-drive towboats. One was Southern Towing Company out of Memphis, TN, and the other a Pacific Northwest company, Shaver Transportation. Less than a half-dozen Z-drive towboats worked the inland river system. Today, we find 10 companies and well over 50 Z-drive towboats built or under construction—and more to come. What caused the change in 8 years?

The inland towing industry is well-versed in navigating the challenging system of inland rivers and canals. It has expertise in adapting to a river’s changing depth, sand bars, currents, and back eddies, and has developed reliable routes and channels that they have followed for years. However, they also expect periodic dramatic changes—such as when a river cuts a new channel to bypass an established one that has silted in. The same is happening with propulsion technology in the industry. Z-drive technology is the cut bank that has broken through to a new and more efficient pathway towards getting the job done. Two companies were instrumental in carving this new path.

Pioneers
The growing popularity of Z-drives in the inland towing industry today is due in large part to two Z-drive pioneers of the distant and recent past—the towboat Miss Nari, and Southern Towing Company.

The Miss Nari, originally named the Delta Cities, was built as a twin-screw conventional towboat in 1951. The boat burned in 1970 and changed hands several times. Eddie Conrad renovated the newly named Miss Nari with Niigata z-drives and diesel engines, and returned it to service in 1982. It is widely accepted that the Miss Nari was the first U.S. towboat to use Z-drive propulsion on the Mississippi River system.

Bill Stegbauer of Southern Towing Company of Memphis, TN, is the more recent pioneer. In the spring of 2006, he began discussions with Ed Shearer of Shearer & Assoc., Inc., to design a new series of 3,200 hp towboats. Following research and discussion, Stegbauer decided to pursue the possibility of a towboat equipped with Z-drives. The first of eight Southern Towing Z-drive towboats went into service in August 2008.

Many factors that led Southern Towing to Z-drive towboats are the same ones driving the change today. However, Southern Towing was the first to step into the deep end of the pool while others stood on the edge, waiting to see whether the Z-drive concept would sink or swim. A key factor in getting others to follow was the empirical data generated by Southern Towing’s fleet, which had multiple opportunities to make side-by-side performance comparisons between conventional and Z-drive towboats pushing identical tows on identical routes.

Performance
Inland towboats are tasked with maneuvering large tows, running at 80% load 24/7 year round, navigating bends, currents and restricted channels, meeting other vessels in close quarters and transiting narrow bridges and locks. Key performance criteria for an inland towboat are its amount of thrust, steering power and maneuverability. Z-drive propulsion has inherent advantages over conventional propulsion in all of these categories. It has a high ratio of converting horsepower to thrust, 50% more backing (astern thrust) power, 50-70% more steering force and, of course, 360° thrust capability.

The advantageous Z-drive thrust and steering performance translate into more efficient and safer operations in most inland towing applications. A critical factor to a towboat’s maneuvering success is its ability to “hold the stern” or “not lose the stern.” That concept is extremely important to a towboat pilot. Whether he or she is going into a lock, making a bridge, or going around a bend, his or her fate rests largely on the ability to control the stern of the towboat, its location in the river, its aspect to the current, and its rate of swing and advance.

Making a bend while heading downstream is an everyday occurrence on the rivers. Flanking and driving a bend are two common techniques used to navigate a bend. Both maneuvers require the pilot to position the stern of the towboat so that the pilot can overcome the tendency of the current to sweep the tow down on the outside of the turn. In the case of driving the bend, the pilot has to have enough steering power to swing the tow and power out of the bend before the towboat ends up on the outside bank. In the case of flanking, the pilot holds the stern more or less stationary over the ground while the current pushes the head end of the tow around. Flanking requires long periods of time and large amounts of power to navigate through relatively short stretches of the river. This is less efficient and uses more fuel but is required if the towboat doesn’t have enough power and maneuverability to drive the bend. A Z-drive towboat with its superior omni-directional thrust may be able to drive the bend in cases where a conventionally propelled towboat would have to flank.

This is one example of Z-drive performance manifesting as operational efficiency in comparison to conventionally propelled towboats. A Z-drive more efficiently transfers main engine horsepower and applies that horsepower to inland towing applications. Put simply, it can do more with less. A Z-drive towboat consumes 20-30% less fuel, has shorter transit times, covers more distance per gallon and pushes a greater number of barges than a conventional towboat of similar horsepower.

Skepticism
The question remains: If Z-drives are so great what took so long? Skepticism to new technology is part of the DNA of the towing industry. And for good reason. The life cycle of a towboat can be 40 to 50 years, requires a large capital outlay and may not produce a return on investment for 5-10 years. You don’t want to make a bad bet that you must live with for 50 years. Questions of initial cost, reliability and maintenance have always been associated with the introduction of new technology, and Z-drives were no exception. What change agents overcame this skepticism? Although performance advantages of Z-drive propulsion are well documented, economic factors were the final push to get the inland towboat industry to accept Z-drive propulsion.

Economic Change Agents
There are five economic change agents:

  • Empirical Performance Data
  • Fleet Modernization
  • Z-drive Construction Cost Parity
  • Critical Mass
  • Competitive Standard

 Empirical Performance Data
The favorable empirical data generated by Southern Towing provided the “real” towboat data proving that the advantages of Z-drive propulsion are not just theoretical; they are a real.

Fleet Modernization
The inland fleet is in the midst of modernization. Much of the existing fleet is at or near the end of its life-cycle and needs to be replaced. Companies are faced with making large capital investments in equipment. Z-drive propulsion must be evaluated in constructing a towboat today that will remain competitive over the next 30 to 50 years.

Z-drive Construction Cost Parity
The difference in construction costs between conventional and Z-drive propelled towboats turns out to be negligible. It was once thought that Z-drives were more expensive to construct. This assumption was based on the price of Z-drive units. However, it has become apparent that the elimination of reduction gears, shafting, rudders and steering systems negate a large portion of the cost difference. There are also maintenance costs that are reduced or eliminated by removing some of the major mechanical components of a conventionally propelled towboat.

Critical Mass
The fact that there are now 50 or more Z-drive towboats in operation and under construction and more on the way has created a critical mass—whereas at one point a Z-drive towboat was a novelty, it is quickly becoming the norm.

The inland towing industry has gone through many major changes. Just two of them are the transition from steam to diesel and paddlewheel to propeller. These changes have increased efficiency, reduced fuel costs and made the industry safer. Clearly, the use of Z-drive propulsion is another such evolution. While it may not be appropriate for all inland towing applications, what was once a unique and rarely used technology is rapidly becoming an industry standard. Towboat companies positioning themselves for the future will be drawn to Z-drive propulsion. Like the rivers they transit every day, the path of the inland towing industry has cut a new channel.

  • Uncategorized

The Evolution of the Z-Drive Inland Towboat

 

Birth of the Z-drive
Z-drive propulsion is over 60 years old. The Rudder Propeller, or Z-drive as we know it today, was developed and built in 1950 by Josef Becker, founder of the present-day Schottel Group. But it wasn’t until the 1980’s that its use began in North America, when it was found predominately in ship assist tugs, not inland towboats. Since the early ‘80’s the Z-drive ship assist tug fleet in North America has grown from a handful to almost 300, tripling in the last 15 years. It continues to grow and is the dominant propulsion in newbuild ship assist tugs.

The inland towboat industry has lagged in adopting Z-drive technology, but is now on the precipice of the same exponential growth experienced in the ship assist market. In 2008, two inland companies utilized Z-drive towboats. One was Southern Towing Company out of Memphis, TN, and the other a Pacific Northwest company, Shaver Transportation. Less than a half-dozen Z-drive towboats worked the inland river system. Today, we find 10 companies and well over 50 Z-drive towboats built or under construction—and more to come. What caused the change in 8 years?

The inland towing industry is well-versed in navigating the challenging system of inland rivers and canals. It has expertise in adapting to a river’s changing depth, sand bars, currents, and back eddies, and has developed reliable routes and channels that they have followed for years. However, they also expect periodic dramatic changes—such as when a river cuts a new channel to bypass an established one that has silted in. The same is happening with propulsion technology in the industry. Z-drive technology is the cut bank that has broken through to a new and more efficient pathway towards getting the job done. Two companies were instrumental in carving this new path.

Pioneers
The growing popularity of Z-drives in the inland towing industry today is due in large part to two Z-drive pioneers of the distant and recent past—the towboat Miss Nari, and Southern Towing Company.

The Miss Nari, originally named the Delta Cities, was built as a twin-screw conventional towboat in 1951. The boat burned in 1970 and changed hands several times. Eddie Conrad renovated the newly named Miss Nari with Niigata z-drives and diesel engines, and returned it to service in 1982. It is widely accepted that the Miss Nari was the first U.S. towboat to use Z-drive propulsion on the Mississippi River system.

Bill Stegbauer of Southern Towing Company of Memphis, TN, is the more recent pioneer. In the spring of 2006, he began discussions with Ed Shearer of Shearer & Assoc., Inc., to design a new series of 3,200 hp towboats. Following research and discussion, Stegbauer decided to pursue the possibility of a towboat equipped with Z-drives. The first of eight Southern Towing Z-drive towboats went into service in August 2008.

Many factors that led Southern Towing to Z-drive towboats are the same ones driving the change today. However, Southern Towing was the first to step into the deep end of the pool while others stood on the edge, waiting to see whether the Z-drive concept would sink or swim. A key factor in getting others to follow was the empirical data generated by Southern Towing’s fleet, which had multiple opportunities to make side-by-side performance comparisons between conventional and Z-drive towboats pushing identical tows on identical routes.

Performance
Inland towboats are tasked with maneuvering large tows, running at 80% load 24/7 year round, navigating bends, currents and restricted channels, meeting other vessels in close quarters and transiting narrow bridges and locks. Key performance criteria for an inland towboat are its amount of thrust, steering power and maneuverability. Z-drive propulsion has inherent advantages over conventional propulsion in all of these categories. It has a high ratio of converting horsepower to thrust, 50% more backing (astern thrust) power, 50-70% more steering force and, of course, 360° thrust capability.

The advantageous Z-drive thrust and steering performance translate into more efficient and safer operations in most inland towing applications. A critical factor to a towboat’s maneuvering success is its ability to “hold the stern” or “not lose the stern.” That concept is extremely important to a towboat pilot. Whether he or she is going into a lock, making a bridge, or going around a bend, his or her fate rests largely on the ability to control the stern of the towboat, its location in the river, its aspect to the current, and its rate of swing and advance.

Making a bend while heading downstream is an everyday occurrence on the rivers. Flanking and driving a bend are two common techniques used to navigate a bend. Both maneuvers require the pilot to position the stern of the towboat so that the pilot can overcome the tendency of the current to sweep the tow down on the outside of the turn. In the case of driving the bend, the pilot has to have enough steering power to swing the tow and power out of the bend before the towboat ends up on the outside bank. In the case of flanking, the pilot holds the stern more or less stationary over the ground while the current pushes the head end of the tow around. Flanking requires long periods of time and large amounts of power to navigate through relatively short stretches of the river. This is less efficient and uses more fuel but is required if the towboat doesn’t have enough power and maneuverability to drive the bend. A Z-drive towboat with its superior omni-directional thrust may be able to drive the bend in cases where a conventionally propelled towboat would have to flank.

This is one example of Z-drive performance manifesting as operational efficiency in comparison to conventionally propelled towboats. A Z-drive more efficiently transfers main engine horsepower and applies that horsepower to inland towing applications. Put simply, it can do more with less. A Z-drive towboat consumes 20-30% less fuel, has shorter transit times, covers more distance per gallon and pushes a greater number of barges than a conventional towboat of similar horsepower.

Skepticism
The question remains: If Z-drives are so great what took so long? Skepticism to new technology is part of the DNA of the towing industry. And for good reason. The life cycle of a towboat can be 40 to 50 years, requires a large capital outlay and may not produce a return on investment for 5-10 years. You don’t want to make a bad bet that you must live with for 50 years. Questions of initial cost, reliability and maintenance have always been associated with the introduction of new technology, and Z-drives were no exception. What change agents overcame this skepticism? Although performance advantages of Z-drive propulsion are well documented, economic factors were the final push to get the inland towboat industry to accept Z-drive propulsion.

Economic Change Agents
There are five economic change agents:

  • Empirical Performance Data
  • Fleet Modernization
  • Z-drive Construction Cost Parity
  • Critical Mass
  • Competitive Standard

 Empirical Performance Data
The favorable empirical data generated by Southern Towing provided the “real” towboat data proving that the advantages of Z-drive propulsion are not just theoretical; they are a real.

Fleet Modernization
The inland fleet is in the midst of modernization. Much of the existing fleet is at or near the end of its life-cycle and needs to be replaced. Companies are faced with making large capital investments in equipment. Z-drive propulsion must be evaluated in constructing a towboat today that will remain competitive over the next 30 to 50 years.

Z-drive Construction Cost Parity
The difference in construction costs between conventional and Z-drive propelled towboats turns out to be negligible. It was once thought that Z-drives were more expensive to construct. This assumption was based on the price of Z-drive units. However, it has become apparent that the elimination of reduction gears, shafting, rudders and steering systems negate a large portion of the cost difference. There are also maintenance costs that are reduced or eliminated by removing some of the major mechanical components of a conventionally propelled towboat.

Critical Mass
The fact that there are now 50 or more Z-drive towboats in operation and under construction and more on the way has created a critical mass—whereas at one point a Z-drive towboat was a novelty, it is quickly becoming the norm.

The inland towing industry has gone through many major changes. Just two of them are the transition from steam to diesel and paddlewheel to propeller. These changes have increased efficiency, reduced fuel costs and made the industry safer. Clearly, the use of Z-drive propulsion is another such evolution. While it may not be appropriate for all inland towing applications, what was once a unique and rarely used technology is rapidly becoming an industry standard. Towboat companies positioning themselves for the future will be drawn to Z-drive propulsion. Like the rivers they transit every day, the path of the inland towing industry has cut a new channel.

  • Uncategorized

The Evolution of the Z-Drive Inland Towboat

 

Birth of the Z-drive
Z-drive propulsion is over 60 years old. The Rudder Propeller, or Z-drive as we know it today, was developed and built in 1950 by Josef Becker, founder of the present-day Schottel Group. But it wasn’t until the 1980’s that its use began in North America, when it was found predominately in ship assist tugs, not inland towboats. Since the early ‘80’s the Z-drive ship assist tug fleet in North America has grown from a handful to almost 300, tripling in the last 15 years. It continues to grow and is the dominant propulsion in newbuild ship assist tugs.

The inland towboat industry has lagged in adopting Z-drive technology, but is now on the precipice of the same exponential growth experienced in the ship assist market. In 2008, two inland companies utilized Z-drive towboats. One was Southern Towing Company out of Memphis, TN, and the other a Pacific Northwest company, Shaver Transportation. Less than a half-dozen Z-drive towboats worked the inland river system. Today, we find 10 companies and well over 50 Z-drive towboats built or under construction—and more to come. What caused the change in 8 years?

The inland towing industry is well-versed in navigating the challenging system of inland rivers and canals. It has expertise in adapting to a river’s changing depth, sand bars, currents, and back eddies, and has developed reliable routes and channels that they have followed for years. However, they also expect periodic dramatic changes—such as when a river cuts a new channel to bypass an established one that has silted in. The same is happening with propulsion technology in the industry. Z-drive technology is the cut bank that has broken through to a new and more efficient pathway towards getting the job done. Two companies were instrumental in carving this new path.

Pioneers
The growing popularity of Z-drives in the inland towing industry today is due in large part to two Z-drive pioneers of the distant and recent past—the towboat Miss Nari, and Southern Towing Company.

The Miss Nari, originally named the Delta Cities, was built as a twin-screw conventional towboat in 1951. The boat burned in 1970 and changed hands several times. Eddie Conrad renovated the newly named Miss Nari with Niigata z-drives and diesel engines, and returned it to service in 1982. It is widely accepted that the Miss Nari was the first U.S. towboat to use Z-drive propulsion on the Mississippi River system.

Bill Stegbauer of Southern Towing Company of Memphis, TN, is the more recent pioneer. In the spring of 2006, he began discussions with Ed Shearer of Shearer & Assoc., Inc., to design a new series of 3,200 hp towboats. Following research and discussion, Stegbauer decided to pursue the possibility of a towboat equipped with Z-drives. The first of eight Southern Towing Z-drive towboats went into service in August 2008.

Many factors that led Southern Towing to Z-drive towboats are the same ones driving the change today. However, Southern Towing was the first to step into the deep end of the pool while others stood on the edge, waiting to see whether the Z-drive concept would sink or swim. A key factor in getting others to follow was the empirical data generated by Southern Towing’s fleet, which had multiple opportunities to make side-by-side performance comparisons between conventional and Z-drive towboats pushing identical tows on identical routes.

Performance
Inland towboats are tasked with maneuvering large tows, running at 80% load 24/7 year round, navigating bends, currents and restricted channels, meeting other vessels in close quarters and transiting narrow bridges and locks. Key performance criteria for an inland towboat are its amount of thrust, steering power and maneuverability. Z-drive propulsion has inherent advantages over conventional propulsion in all of these categories. It has a high ratio of converting horsepower to thrust, 50% more backing (astern thrust) power, 50-70% more steering force and, of course, 360° thrust capability.

The advantageous Z-drive thrust and steering performance translate into more efficient and safer operations in most inland towing applications. A critical factor to a towboat’s maneuvering success is its ability to “hold the stern” or “not lose the stern.” That concept is extremely important to a towboat pilot. Whether he or she is going into a lock, making a bridge, or going around a bend, his or her fate rests largely on the ability to control the stern of the towboat, its location in the river, its aspect to the current, and its rate of swing and advance.

Making a bend while heading downstream is an everyday occurrence on the rivers. Flanking and driving a bend are two common techniques used to navigate a bend. Both maneuvers require the pilot to position the stern of the towboat so that the pilot can overcome the tendency of the current to sweep the tow down on the outside of the turn. In the case of driving the bend, the pilot has to have enough steering power to swing the tow and power out of the bend before the towboat ends up on the outside bank. In the case of flanking, the pilot holds the stern more or less stationary over the ground while the current pushes the head end of the tow around. Flanking requires long periods of time and large amounts of power to navigate through relatively short stretches of the river. This is less efficient and uses more fuel but is required if the towboat doesn’t have enough power and maneuverability to drive the bend. A Z-drive towboat with its superior omni-directional thrust may be able to drive the bend in cases where a conventionally propelled towboat would have to flank.

This is one example of Z-drive performance manifesting as operational efficiency in comparison to conventionally propelled towboats. A Z-drive more efficiently transfers main engine horsepower and applies that horsepower to inland towing applications. Put simply, it can do more with less. A Z-drive towboat consumes 20-30% less fuel, has shorter transit times, covers more distance per gallon and pushes a greater number of barges than a conventional towboat of similar horsepower.

Skepticism
The question remains: If Z-drives are so great what took so long? Skepticism to new technology is part of the DNA of the towing industry. And for good reason. The life cycle of a towboat can be 40 to 50 years, requires a large capital outlay and may not produce a return on investment for 5-10 years. You don’t want to make a bad bet that you must live with for 50 years. Questions of initial cost, reliability and maintenance have always been associated with the introduction of new technology, and Z-drives were no exception. What change agents overcame this skepticism? Although performance advantages of Z-drive propulsion are well documented, economic factors were the final push to get the inland towboat industry to accept Z-drive propulsion.

Economic Change Agents
There are five economic change agents:

  • Empirical Performance Data
  • Fleet Modernization
  • Z-drive Construction Cost Parity
  • Critical Mass
  • Competitive Standard

 Empirical Performance Data
The favorable empirical data generated by Southern Towing provided the “real” towboat data proving that the advantages of Z-drive propulsion are not just theoretical; they are a real.

Fleet Modernization
The inland fleet is in the midst of modernization. Much of the existing fleet is at or near the end of its life-cycle and needs to be replaced. Companies are faced with making large capital investments in equipment. Z-drive propulsion must be evaluated in constructing a towboat today that will remain competitive over the next 30 to 50 years.

Z-drive Construction Cost Parity
The difference in construction costs between conventional and Z-drive propelled towboats turns out to be negligible. It was once thought that Z-drives were more expensive to construct. This assumption was based on the price of Z-drive units. However, it has become apparent that the elimination of reduction gears, shafting, rudders and steering systems negate a large portion of the cost difference. There are also maintenance costs that are reduced or eliminated by removing some of the major mechanical components of a conventionally propelled towboat.

Critical Mass
The fact that there are now 50 or more Z-drive towboats in operation and under construction and more on the way has created a critical mass—whereas at one point a Z-drive towboat was a novelty, it is quickly becoming the norm.

The inland towing industry has gone through many major changes. Just two of them are the transition from steam to diesel and paddlewheel to propeller. These changes have increased efficiency, reduced fuel costs and made the industry safer. Clearly, the use of Z-drive propulsion is another such evolution. While it may not be appropriate for all inland towing applications, what was once a unique and rarely used technology is rapidly becoming an industry standard. Towboat companies positioning themselves for the future will be drawn to Z-drive propulsion. Like the rivers they transit every day, the path of the inland towing industry has cut a new channel.

  • Uncategorized

The Evolution of the Z-Drive Inland Towboat

 

Birth of the Z-drive
Z-drive propulsion is over 60 years old. The Rudder Propeller, or Z-drive as we know it today, was developed and built in 1950 by Josef Becker, founder of the present-day Schottel Group. But it wasn’t until the 1980’s that its use began in North America, when it was found predominately in ship assist tugs, not inland towboats. Since the early ‘80’s the Z-drive ship assist tug fleet in North America has grown from a handful to almost 300, tripling in the last 15 years. It continues to grow and is the dominant propulsion in newbuild ship assist tugs.

The inland towboat industry has lagged in adopting Z-drive technology, but is now on the precipice of the same exponential growth experienced in the ship assist market. In 2008, two inland companies utilized Z-drive towboats. One was Southern Towing Company out of Memphis, TN, and the other a Pacific Northwest company, Shaver Transportation. Less than a half-dozen Z-drive towboats worked the inland river system. Today, we find 10 companies and well over 50 Z-drive towboats built or under construction—and more to come. What caused the change in 8 years?

The inland towing industry is well-versed in navigating the challenging system of inland rivers and canals. It has expertise in adapting to a river’s changing depth, sand bars, currents, and back eddies, and has developed reliable routes and channels that they have followed for years. However, they also expect periodic dramatic changes—such as when a river cuts a new channel to bypass an established one that has silted in. The same is happening with propulsion technology in the industry. Z-drive technology is the cut bank that has broken through to a new and more efficient pathway towards getting the job done. Two companies were instrumental in carving this new path.

Pioneers
The growing popularity of Z-drives in the inland towing industry today is due in large part to two Z-drive pioneers of the distant and recent past—the towboat Miss Nari, and Southern Towing Company.

The Miss Nari, originally named the Delta Cities, was built as a twin-screw conventional towboat in 1951. The boat burned in 1970 and changed hands several times. Eddie Conrad renovated the newly named Miss Nari with Niigata z-drives and diesel engines, and returned it to service in 1982. It is widely accepted that the Miss Nari was the first U.S. towboat to use Z-drive propulsion on the Mississippi River system.

Bill Stegbauer of Southern Towing Company of Memphis, TN, is the more recent pioneer. In the spring of 2006, he began discussions with Ed Shearer of Shearer & Assoc., Inc., to design a new series of 3,200 hp towboats. Following research and discussion, Stegbauer decided to pursue the possibility of a towboat equipped with Z-drives. The first of eight Southern Towing Z-drive towboats went into service in August 2008.

Many factors that led Southern Towing to Z-drive towboats are the same ones driving the change today. However, Southern Towing was the first to step into the deep end of the pool while others stood on the edge, waiting to see whether the Z-drive concept would sink or swim. A key factor in getting others to follow was the empirical data generated by Southern Towing’s fleet, which had multiple opportunities to make side-by-side performance comparisons between conventional and Z-drive towboats pushing identical tows on identical routes.

Performance
Inland towboats are tasked with maneuvering large tows, running at 80% load 24/7 year round, navigating bends, currents and restricted channels, meeting other vessels in close quarters and transiting narrow bridges and locks. Key performance criteria for an inland towboat are its amount of thrust, steering power and maneuverability. Z-drive propulsion has inherent advantages over conventional propulsion in all of these categories. It has a high ratio of converting horsepower to thrust, 50% more backing (astern thrust) power, 50-70% more steering force and, of course, 360° thrust capability.

The advantageous Z-drive thrust and steering performance translate into more efficient and safer operations in most inland towing applications. A critical factor to a towboat’s maneuvering success is its ability to “hold the stern” or “not lose the stern.” That concept is extremely important to a towboat pilot. Whether he or she is going into a lock, making a bridge, or going around a bend, his or her fate rests largely on the ability to control the stern of the towboat, its location in the river, its aspect to the current, and its rate of swing and advance.

Making a bend while heading downstream is an everyday occurrence on the rivers. Flanking and driving a bend are two common techniques used to navigate a bend. Both maneuvers require the pilot to position the stern of the towboat so that the pilot can overcome the tendency of the current to sweep the tow down on the outside of the turn. In the case of driving the bend, the pilot has to have enough steering power to swing the tow and power out of the bend before the towboat ends up on the outside bank. In the case of flanking, the pilot holds the stern more or less stationary over the ground while the current pushes the head end of the tow around. Flanking requires long periods of time and large amounts of power to navigate through relatively short stretches of the river. This is less efficient and uses more fuel but is required if the towboat doesn’t have enough power and maneuverability to drive the bend. A Z-drive towboat with its superior omni-directional thrust may be able to drive the bend in cases where a conventionally propelled towboat would have to flank.

This is one example of Z-drive performance manifesting as operational efficiency in comparison to conventionally propelled towboats. A Z-drive more efficiently transfers main engine horsepower and applies that horsepower to inland towing applications. Put simply, it can do more with less. A Z-drive towboat consumes 20-30% less fuel, has shorter transit times, covers more distance per gallon and pushes a greater number of barges than a conventional towboat of similar horsepower.

Skepticism
The question remains: If Z-drives are so great what took so long? Skepticism to new technology is part of the DNA of the towing industry. And for good reason. The life cycle of a towboat can be 40 to 50 years, requires a large capital outlay and may not produce a return on investment for 5-10 years. You don’t want to make a bad bet that you must live with for 50 years. Questions of initial cost, reliability and maintenance have always been associated with the introduction of new technology, and Z-drives were no exception. What change agents overcame this skepticism? Although performance advantages of Z-drive propulsion are well documented, economic factors were the final push to get the inland towboat industry to accept Z-drive propulsion.

Economic Change Agents
There are five economic change agents:

  • Empirical Performance Data
  • Fleet Modernization
  • Z-drive Construction Cost Parity
  • Critical Mass
  • Competitive Standard

 Empirical Performance Data
The favorable empirical data generated by Southern Towing provided the “real” towboat data proving that the advantages of Z-drive propulsion are not just theoretical; they are a real.

Fleet Modernization
The inland fleet is in the midst of modernization. Much of the existing fleet is at or near the end of its life-cycle and needs to be replaced. Companies are faced with making large capital investments in equipment. Z-drive propulsion must be evaluated in constructing a towboat today that will remain competitive over the next 30 to 50 years.

Z-drive Construction Cost Parity
The difference in construction costs between conventional and Z-drive propelled towboats turns out to be negligible. It was once thought that Z-drives were more expensive to construct. This assumption was based on the price of Z-drive units. However, it has become apparent that the elimination of reduction gears, shafting, rudders and steering systems negate a large portion of the cost difference. There are also maintenance costs that are reduced or eliminated by removing some of the major mechanical components of a conventionally propelled towboat.

Critical Mass
The fact that there are now 50 or more Z-drive towboats in operation and under construction and more on the way has created a critical mass—whereas at one point a Z-drive towboat was a novelty, it is quickly becoming the norm.

The inland towing industry has gone through many major changes. Just two of them are the transition from steam to diesel and paddlewheel to propeller. These changes have increased efficiency, reduced fuel costs and made the industry safer. Clearly, the use of Z-drive propulsion is another such evolution. While it may not be appropriate for all inland towing applications, what was once a unique and rarely used technology is rapidly becoming an industry standard. Towboat companies positioning themselves for the future will be drawn to Z-drive propulsion. Like the rivers they transit every day, the path of the inland towing industry has cut a new channel.

  • Uncategorized

The Evolution of the Z-Drive Inland Towboat

 

Birth of the Z-drive
Z-drive propulsion is over 60 years old. The Rudder Propeller, or Z-drive as we know it today, was developed and built in 1950 by Josef Becker, founder of the present-day Schottel Group. But it wasn’t until the 1980’s that its use began in North America, when it was found predominately in ship assist tugs, not inland towboats. Since the early ‘80’s the Z-drive ship assist tug fleet in North America has grown from a handful to almost 300, tripling in the last 15 years. It continues to grow and is the dominant propulsion in newbuild ship assist tugs.

The inland towboat industry has lagged in adopting Z-drive technology, but is now on the precipice of the same exponential growth experienced in the ship assist market. In 2008, two inland companies utilized Z-drive towboats. One was Southern Towing Company out of Memphis, TN, and the other a Pacific Northwest company, Shaver Transportation. Less than a half-dozen Z-drive towboats worked the inland river system. Today, we find 10 companies and well over 50 Z-drive towboats built or under construction—and more to come. What caused the change in 8 years?

The inland towing industry is well-versed in navigating the challenging system of inland rivers and canals. It has expertise in adapting to a river’s changing depth, sand bars, currents, and back eddies, and has developed reliable routes and channels that they have followed for years. However, they also expect periodic dramatic changes—such as when a river cuts a new channel to bypass an established one that has silted in. The same is happening with propulsion technology in the industry. Z-drive technology is the cut bank that has broken through to a new and more efficient pathway towards getting the job done. Two companies were instrumental in carving this new path.

Pioneers
The growing popularity of Z-drives in the inland towing industry today is due in large part to two Z-drive pioneers of the distant and recent past—the towboat Miss Nari, and Southern Towing Company.

The Miss Nari, originally named the Delta Cities, was built as a twin-screw conventional towboat in 1951. The boat burned in 1970 and changed hands several times. Eddie Conrad renovated the newly named Miss Nari with Niigata z-drives and diesel engines, and returned it to service in 1982. It is widely accepted that the Miss Nari was the first U.S. towboat to use Z-drive propulsion on the Mississippi River system.

Bill Stegbauer of Southern Towing Company of Memphis, TN, is the more recent pioneer. In the spring of 2006, he began discussions with Ed Shearer of Shearer & Assoc., Inc., to design a new series of 3,200 hp towboats. Following research and discussion, Stegbauer decided to pursue the possibility of a towboat equipped with Z-drives. The first of eight Southern Towing Z-drive towboats went into service in August 2008.

Many factors that led Southern Towing to Z-drive towboats are the same ones driving the change today. However, Southern Towing was the first to step into the deep end of the pool while others stood on the edge, waiting to see whether the Z-drive concept would sink or swim. A key factor in getting others to follow was the empirical data generated by Southern Towing’s fleet, which had multiple opportunities to make side-by-side performance comparisons between conventional and Z-drive towboats pushing identical tows on identical routes.

Performance
Inland towboats are tasked with maneuvering large tows, running at 80% load 24/7 year round, navigating bends, currents and restricted channels, meeting other vessels in close quarters and transiting narrow bridges and locks. Key performance criteria for an inland towboat are its amount of thrust, steering power and maneuverability. Z-drive propulsion has inherent advantages over conventional propulsion in all of these categories. It has a high ratio of converting horsepower to thrust, 50% more backing (astern thrust) power, 50-70% more steering force and, of course, 360° thrust capability.

The advantageous Z-drive thrust and steering performance translate into more efficient and safer operations in most inland towing applications. A critical factor to a towboat’s maneuvering success is its ability to “hold the stern” or “not lose the stern.” That concept is extremely important to a towboat pilot. Whether he or she is going into a lock, making a bridge, or going around a bend, his or her fate rests largely on the ability to control the stern of the towboat, its location in the river, its aspect to the current, and its rate of swing and advance.

Making a bend while heading downstream is an everyday occurrence on the rivers. Flanking and driving a bend are two common techniques used to navigate a bend. Both maneuvers require the pilot to position the stern of the towboat so that the pilot can overcome the tendency of the current to sweep the tow down on the outside of the turn. In the case of driving the bend, the pilot has to have enough steering power to swing the tow and power out of the bend before the towboat ends up on the outside bank. In the case of flanking, the pilot holds the stern more or less stationary over the ground while the current pushes the head end of the tow around. Flanking requires long periods of time and large amounts of power to navigate through relatively short stretches of the river. This is less efficient and uses more fuel but is required if the towboat doesn’t have enough power and maneuverability to drive the bend. A Z-drive towboat with its superior omni-directional thrust may be able to drive the bend in cases where a conventionally propelled towboat would have to flank.

This is one example of Z-drive performance manifesting as operational efficiency in comparison to conventionally propelled towboats. A Z-drive more efficiently transfers main engine horsepower and applies that horsepower to inland towing applications. Put simply, it can do more with less. A Z-drive towboat consumes 20-30% less fuel, has shorter transit times, covers more distance per gallon and pushes a greater number of barges than a conventional towboat of similar horsepower.

Skepticism
The question remains: If Z-drives are so great what took so long? Skepticism to new technology is part of the DNA of the towing industry. And for good reason. The life cycle of a towboat can be 40 to 50 years, requires a large capital outlay and may not produce a return on investment for 5-10 years. You don’t want to make a bad bet that you must live with for 50 years. Questions of initial cost, reliability and maintenance have always been associated with the introduction of new technology, and Z-drives were no exception. What change agents overcame this skepticism? Although performance advantages of Z-drive propulsion are well documented, economic factors were the final push to get the inland towboat industry to accept Z-drive propulsion.

Economic Change Agents
There are five economic change agents:

  • Empirical Performance Data
  • Fleet Modernization
  • Z-drive Construction Cost Parity
  • Critical Mass
  • Competitive Standard

 Empirical Performance Data
The favorable empirical data generated by Southern Towing provided the “real” towboat data proving that the advantages of Z-drive propulsion are not just theoretical; they are a real.

Fleet Modernization
The inland fleet is in the midst of modernization. Much of the existing fleet is at or near the end of its life-cycle and needs to be replaced. Companies are faced with making large capital investments in equipment. Z-drive propulsion must be evaluated in constructing a towboat today that will remain competitive over the next 30 to 50 years.

Z-drive Construction Cost Parity
The difference in construction costs between conventional and Z-drive propelled towboats turns out to be negligible. It was once thought that Z-drives were more expensive to construct. This assumption was based on the price of Z-drive units. However, it has become apparent that the elimination of reduction gears, shafting, rudders and steering systems negate a large portion of the cost difference. There are also maintenance costs that are reduced or eliminated by removing some of the major mechanical components of a conventionally propelled towboat.

Critical Mass
The fact that there are now 50 or more Z-drive towboats in operation and under construction and more on the way has created a critical mass—whereas at one point a Z-drive towboat was a novelty, it is quickly becoming the norm.

The inland towing industry has gone through many major changes. Just two of them are the transition from steam to diesel and paddlewheel to propeller. These changes have increased efficiency, reduced fuel costs and made the industry safer. Clearly, the use of Z-drive propulsion is another such evolution. While it may not be appropriate for all inland towing applications, what was once a unique and rarely used technology is rapidly becoming an industry standard. Towboat companies positioning themselves for the future will be drawn to Z-drive propulsion. Like the rivers they transit every day, the path of the inland towing industry has cut a new channel.

  • Uncategorized

The Evolution of the Z-Drive Inland Towboat

 

Birth of the Z-drive
Z-drive propulsion is over 60 years old. The Rudder Propeller, or Z-drive as we know it today, was developed and built in 1950 by Josef Becker, founder of the present-day Schottel Group. But it wasn’t until the 1980’s that its use began in North America, when it was found predominately in ship assist tugs, not inland towboats. Since the early ‘80’s the Z-drive ship assist tug fleet in North America has grown from a handful to almost 300, tripling in the last 15 years. It continues to grow and is the dominant propulsion in newbuild ship assist tugs.

The inland towboat industry has lagged in adopting Z-drive technology, but is now on the precipice of the same exponential growth experienced in the ship assist market. In 2008, two inland companies utilized Z-drive towboats. One was Southern Towing Company out of Memphis, TN, and the other a Pacific Northwest company, Shaver Transportation. Less than a half-dozen Z-drive towboats worked the inland river system. Today, we find 10 companies and well over 50 Z-drive towboats built or under construction—and more to come. What caused the change in 8 years?

The inland towing industry is well-versed in navigating the challenging system of inland rivers and canals. It has expertise in adapting to a river’s changing depth, sand bars, currents, and back eddies, and has developed reliable routes and channels that they have followed for years. However, they also expect periodic dramatic changes—such as when a river cuts a new channel to bypass an established one that has silted in. The same is happening with propulsion technology in the industry. Z-drive technology is the cut bank that has broken through to a new and more efficient pathway towards getting the job done. Two companies were instrumental in carving this new path.

Pioneers
The growing popularity of Z-drives in the inland towing industry today is due in large part to two Z-drive pioneers of the distant and recent past—the towboat Miss Nari, and Southern Towing Company.

The Miss Nari, originally named the Delta Cities, was built as a twin-screw conventional towboat in 1951. The boat burned in 1970 and changed hands several times. Eddie Conrad renovated the newly named Miss Nari with Niigata z-drives and diesel engines, and returned it to service in 1982. It is widely accepted that the Miss Nari was the first U.S. towboat to use Z-drive propulsion on the Mississippi River system.

Bill Stegbauer of Southern Towing Company of Memphis, TN, is the more recent pioneer. In the spring of 2006, he began discussions with Ed Shearer of Shearer & Assoc., Inc., to design a new series of 3,200 hp towboats. Following research and discussion, Stegbauer decided to pursue the possibility of a towboat equipped with Z-drives. The first of eight Southern Towing Z-drive towboats went into service in August 2008.

Many factors that led Southern Towing to Z-drive towboats are the same ones driving the change today. However, Southern Towing was the first to step into the deep end of the pool while others stood on the edge, waiting to see whether the Z-drive concept would sink or swim. A key factor in getting others to follow was the empirical data generated by Southern Towing’s fleet, which had multiple opportunities to make side-by-side performance comparisons between conventional and Z-drive towboats pushing identical tows on identical routes.

Performance
Inland towboats are tasked with maneuvering large tows, running at 80% load 24/7 year round, navigating bends, currents and restricted channels, meeting other vessels in close quarters and transiting narrow bridges and locks. Key performance criteria for an inland towboat are its amount of thrust, steering power and maneuverability. Z-drive propulsion has inherent advantages over conventional propulsion in all of these categories. It has a high ratio of converting horsepower to thrust, 50% more backing (astern thrust) power, 50-70% more steering force and, of course, 360° thrust capability.

The advantageous Z-drive thrust and steering performance translate into more efficient and safer operations in most inland towing applications. A critical factor to a towboat’s maneuvering success is its ability to “hold the stern” or “not lose the stern.” That concept is extremely important to a towboat pilot. Whether he or she is going into a lock, making a bridge, or going around a bend, his or her fate rests largely on the ability to control the stern of the towboat, its location in the river, its aspect to the current, and its rate of swing and advance.

Making a bend while heading downstream is an everyday occurrence on the rivers. Flanking and driving a bend are two common techniques used to navigate a bend. Both maneuvers require the pilot to position the stern of the towboat so that the pilot can overcome the tendency of the current to sweep the tow down on the outside of the turn. In the case of driving the bend, the pilot has to have enough steering power to swing the tow and power out of the bend before the towboat ends up on the outside bank. In the case of flanking, the pilot holds the stern more or less stationary over the ground while the current pushes the head end of the tow around. Flanking requires long periods of time and large amounts of power to navigate through relatively short stretches of the river. This is less efficient and uses more fuel but is required if the towboat doesn’t have enough power and maneuverability to drive the bend. A Z-drive towboat with its superior omni-directional thrust may be able to drive the bend in cases where a conventionally propelled towboat would have to flank.

This is one example of Z-drive performance manifesting as operational efficiency in comparison to conventionally propelled towboats. A Z-drive more efficiently transfers main engine horsepower and applies that horsepower to inland towing applications. Put simply, it can do more with less. A Z-drive towboat consumes 20-30% less fuel, has shorter transit times, covers more distance per gallon and pushes a greater number of barges than a conventional towboat of similar horsepower.

Skepticism
The question remains: If Z-drives are so great what took so long? Skepticism to new technology is part of the DNA of the towing industry. And for good reason. The life cycle of a towboat can be 40 to 50 years, requires a large capital outlay and may not produce a return on investment for 5-10 years. You don’t want to make a bad bet that you must live with for 50 years. Questions of initial cost, reliability and maintenance have always been associated with the introduction of new technology, and Z-drives were no exception. What change agents overcame this skepticism? Although performance advantages of Z-drive propulsion are well documented, economic factors were the final push to get the inland towboat industry to accept Z-drive propulsion.

Economic Change Agents
There are five economic change agents:

  • Empirical Performance Data
  • Fleet Modernization
  • Z-drive Construction Cost Parity
  • Critical Mass
  • Competitive Standard

 Empirical Performance Data
The favorable empirical data generated by Southern Towing provided the “real” towboat data proving that the advantages of Z-drive propulsion are not just theoretical; they are a real.

Fleet Modernization
The inland fleet is in the midst of modernization. Much of the existing fleet is at or near the end of its life-cycle and needs to be replaced. Companies are faced with making large capital investments in equipment. Z-drive propulsion must be evaluated in constructing a towboat today that will remain competitive over the next 30 to 50 years.

Z-drive Construction Cost Parity
The difference in construction costs between conventional and Z-drive propelled towboats turns out to be negligible. It was once thought that Z-drives were more expensive to construct. This assumption was based on the price of Z-drive units. However, it has become apparent that the elimination of reduction gears, shafting, rudders and steering systems negate a large portion of the cost difference. There are also maintenance costs that are reduced or eliminated by removing some of the major mechanical components of a conventionally propelled towboat.

Critical Mass
The fact that there are now 50 or more Z-drive towboats in operation and under construction and more on the way has created a critical mass—whereas at one point a Z-drive towboat was a novelty, it is quickly becoming the norm.

The inland towing industry has gone through many major changes. Just two of them are the transition from steam to diesel and paddlewheel to propeller. These changes have increased efficiency, reduced fuel costs and made the industry safer. Clearly, the use of Z-drive propulsion is another such evolution. While it may not be appropriate for all inland towing applications, what was once a unique and rarely used technology is rapidly becoming an industry standard. Towboat companies positioning themselves for the future will be drawn to Z-drive propulsion. Like the rivers they transit every day, the path of the inland towing industry has cut a new channel.

New Blood: U.S. Army set to order new vessels

 

Last year, the agency announced that it would order a new series of vessels—up to 37 in total for about $450 million— known as the Maneuver Support Vessel (Light), MSV(L) for its watercraft fleet. At print time, no RFP had been released, but it is expected to be issued in the next few weeks. The Army currently has a fleet of 132 vessels that perform a large percentage of the U.S. forces’ equipment and supply deliveries. Missions for the fleet are broken up into four categories: (1) Landing Craft; (2) Ship-to-Shore Enablers; (3) Towing and Terminal Support Operations; (4) Watercraft Operations Support.

The U.S. Army’s fleet is meant to be deployed worldwide, and can support operational movement and maneuver and force repositioning. Additionally, the agency says, the vessels perform a variety of roles.

Vessel type is broken up into two categories:

  1. (1) Lighters, which are used to conduct heavy sustainment lift; transport outsized equipment; Lighterage (cargo); and personnel between ships, from ship-to-shore, or from intra-theater transport. The Army says lighters are further classified into conventional displacement (landing craft) or modular causeway systems (powered ferry). Examples of lighters include: Logistic Support Vessel (LSV); Landing Craft, Utility (LCU); Landing Craft, Mechanized (LCM); and Causeway Ferry.
  2. (2) Floating Utility Craft, which perform operations incidental to water terminal operations (except Lighterage service); this can include harbor and oceangoing tugs; floating cranes, floating causeways, roll-on/roll-off discharge facilities (RRDF), and modular/side-loadable warping tugs.

Details on the MSV(L)
The upcoming MSV(L) will replace the Landing Craft Mechanized 8 (LCM-8) (pictured above), which has been in service since 1967. The LCM-8 travels at 12 knots with no load and 8 knots or less with load. The LCM-8 is small in size, measuring just 74 ft x 21 ft, and can be used in confined areas. It has a range of 332 nautical miles unloaded and 271 nautical miles loaded. Designed for operations in rough waters, the LCM-8 can maneuver through sea state 3, breakers and can ground on a beach. Its bow ramp enables roll-on / roll-off (RO/RO) operations with wheeled and tracked vehicles.

The MSV(L) will feature an increased payload and speed over its predecessor, LCM-8.

The introduction of the MSV(L) into the fleet, says the Army, “will enable the agency to meet its movement, maneuver, and integrated expeditionary sustainment requirements with a more agile, versatile; and capable platform. The MSV(L) will conduct movement and maneuver of tactical force elements as well as traditional Army Watercraft System sustainment operations.”

The MSV(L) will also be able to operate in a variety bodies of waters including coastal waters, rivers and narrow waterways.

According to the agency, Col. Michael M. Russell Sr. Army G-8 FD Division Chief, called the MSV(L) program a lynchpin to the Army’s watercraft strategy. The landing craft will have the ability and capacity to carry a tank, a Joint Light Tactical Vehicle (JLTV), a Stryker armored fighting vehicle, troops, or supplies.

Russell added that the system would not be designed from scratch, and will likely be based on an existing design that will be “ruggedized” and made to fit the Army’s mission profile.

Industry Players Express Interest
One of the designs expected to be in the running is Constructions Industrielles de la Méditerranée’s (CNIM) L-Cat design.

Last December it was announced the CNIM would team up with Fincantieri Marine Group (FMG), the U.S. subsidiary of Fincantieri, Oshkosh Defense, LLC, and Watercraft Logistics Services (WLS) to pursue the contract.

The L-Cat (Landing Catamaran Craft) is an innovative and rapid amphibious ship with a RO/RO design that integrates a mobile loading platform in a catamaran hull. This enables for personnel, armored vehicles and equipment to be unloaded in areas where there are no port facilities and shallow waters.

Intended for shore-to-shore applications, the L-Cat is already successfully used by the French National Navy, under the name EDA-R.

CNIM says that “during amphibious operations, it (the L-Cat) guarantees optimal transit speed, rapid loading and unloading of the deck.” This helps reduce threat during exposure time and offers a high degree of autonomy, with the vessel able to operate in a rage of 500 to 700 nautical miles, depending on the load.

Measuring 30 m x 12.6 m, the L-Cat has a maximum payload capacity of 100 tonnes, can reach speeds of up to 30 knots when empty and 18 knots when loaded to maximum payload.

The design’s proven track record, along with its own successful history of building vessels for the Army, Coast Guard and Navy, makes the group the optimal choice for the MSV(L) build program, according to Francesco G. Valente, President and CEO of FMG. “We believe that our world-class team and proven design represent the lowest risk and lowest total life-cycle cost to the U.S. Army,” said Valente.

Valente notes that FMG shipyards—Fincantieri Marinette Marine, Fincantieri Bay Shipbuilding and Fincantieri Ace Marine—have experience in building these types of landing craft, having built the LCM-6, LCM-8 and LCU landing craft in Marinette. The shipbuilder has also had the distinction of building 562 landing craft for the Army and Navy over a period of 23-years. And Marinette Marine was also half of the RB-M team (Kvichak Industries the other half) that built the Response Boat-Medium for the U.S. Coast Guard.

Meeting Production Needs, Who Wants In?
According to the Army’s MSV(L) DRAFT-Production Schedule, it is expected that one prototype will be built and tested by FY19, four will be built during Low Rate Initial Production (LRIP) between FY 21 and FY 22; and, should the program reach full scale production, 32 will be produced during a four-year period between FY23 through FY27.

Kvichak, formerly known as Kvichak Marine Industries, now part of the Vigor group of companies, could also be a contender should it choose to pursue the contract.

The boat builder is listed on the Army’s list of Interested Prime Contractors along with Bollinger Shipyards, Conrad Shipyards, Ingalls Shipbuilding, Derecktor, Sterling Shipyard, Swiftships, LLC, and United States Marine, Inc.—the list is a prime example of the variety of yards interested in the contract, as well as the agency’s willingness to open up the contract pursuit to all shipyard types.

Kvichak is no stranger to producing vessels for government agencies in a full-scale production cycle, having long been a builder of pilot and patrol boats. Most notably, Kvichak was the other half of Team RB-M. The team built and delivered 174 RB-Ms for the Coast Guard, on time and on budget, completing the program in 2015.

The other builders on the list also have diverse portfolios, making each a feasible choice for the MSV(L) program.

Bollinger has long been a builder of patrol vessels for both the U.S. Coast Guard and U.S. Navy. Most recently delivering the 17th Fast Response Cutter to the U.S. Coast Guard.

Conrad has, perhaps, the most diverse portfolio, with experience in the construction, conversion and repair of a wide variety of steel and aluminum marine vessels across its shipyards for both commercial and government customers—Conrad’s Orange shipyard has produced a number of vessels for the army. Conrad, as most are aware, is currently building the first LNG bunker barge for operation in U.S.

Derecktor could put itself back in the shipbuilding game big time, should it win this contract. The yard has seen its share of trouble over the last decade, having filed for bankruptcy in Connecticut and losing its Bridgeport facility in the process, but Derecktor is putting in the work to get itself to the level it once was. The builder has experience building a variety of innovative vessel types both in the commercial and private yacht sector, including ferries, security vessels, patrol crafts, research vessels and workboats.

Ingalls Shipbuilding, a division of Huntington Ingalls Industries, has an extensive history with both the Coast Guard and Navy. Ingalls is currently building vessel 6 through 8 in the National Security Cutter Program for the Coast Guard’s fleet at its Pascagoula, MS shipyard. Under the program, eight vessels will be built to replace the aging 378-ft high endurance cutters. The shipbuilder also recently announced that the U.S. Navy’s 10th San Antonio-class amphibious transport dock, John P. Murtha (LPD 26), successfully completed acceptance trials. Under its contract with the Navy, Ingalls has built and delivered nine ships in the San Antonio Class. LPD 26 will be delivered in May. The 11th LPD, Portland (LPD 27) will be christened later this month. The yard has also received advanced procurement funding for long-lead-time material for the 12th ship in the series, the LPD 28.

Texas-based Sterling Shipyard, started by Harry Murdock and Brad Taylor, formerly of Orange Shipbuilding, has built a number of tank barges and towboats.

Swiftships specializes in the construction of small to medium-sized vessels made with steel, aluminum and fiberglass. It has delivered boats to the U.S. military, both commercial and private companies and 52 foreign countries.

United States Marine, Inc., Gulfport, MS, a designer and builder of fast patrol and special operations craft for the U.S. and foreign militaries, has predominately been a builder of military, patrol and special warfare boats in the 21 ft to 90 ft range. In its 30 plus years in business it has delivered over 500 craft to the U.S. Navy, USSCOCOM, NAVSEA and foreign militaries.