MARCH 26, 2016—Over the years, Rodriguez Shipbuilding, Inc.’s triple-screw towboats have won a following operating in the shallow waters where the Mississippi River meets the Gulf of Mexico. These Lugger-type vessels are
Tucked away in southwestern Finland is Salo, a town of about 50,000, where 40 percent of all the doors for large cruise ships are produced. Antti Marine’s production facility in Salo has produced a quarter of a million doors for 300 cruise ships in just over 20 years. It takes about 10 weeks to produce a typical order of 3,000 doors. They are supplied over a period of six months, as and when the ship’s cabins are built
“We are devoted to lean thinking,” says Commercial Director Markko Takkinen. “The production time of the doors is short, as we do not want them remain in storage here.”
Antti Marine specializes in what it calls ‘“tailored mass production”—necessary because on one cruise ship there may be 150 different types of doors.
Antti Marine is not the only Finnish marine company that benefits from many of the world’s large cruise ship fleet being built in Finland.
Cruise ships also have a lot of toilets and a need for a lot of waste management systems. Finnish headquartered Evac Group has just received its biggest cruise vessel contract ever: total waste management systems for four large cruise ships plus an option to outfit an additional six vessels. The initial four-vessel contract is valued at about EURO 30 million.
Each ship will have an Evac Cleansea wastewater treatment plan, allowing operation in Environmentally Sensitive Sea Areas (ESSAs) and Special Areas (SAs), dry and wet waste treatment systems, a bio sludge treatment unit, plus vacuum collecting systems and some 3,000 vacuum toilets.
Evac also supplies its products to a wide range of users ashore and afloat. So, too, does fire protection specialist Marioff Corporation Oy, but its roots are in the marine market and it last year launched a new generation Hi-Fog 3000 sprinkler series for marine applications that replaces earlier Hi-Fog 1000 and Hi-Fog 2000 sprinkler series.
“With the launch of this new generation of Hi-Fog 3000 sprinklers, we are offering to our marine customers enhanced Hi-Fog systems with faster activation, more efficient suppression and improved passenger and crew safety,” says John Hemgård, Director of Marine Business, Marioff Corporation Oy.
The Hi-Fog 3000 sprinkler series is designed, tested and type approved according to IMO Res.A800(19) as amended in IMO Res.MSC.265(84).
Another Finnish product that really took off after its widespread adoption is ABB’s Azipod. It’s become the propulsor of choice for cruise ships and ABB is currently delivering the complete electrical power plant and propulsion systems for two new 3,300 passenger cruise ships building at Germany’s Meyer Werft. The 20.5 MW Azipod XO propulsion unit for the first of the ships recently left the ABB factory in Helsinki.
ABB has delivered, or has on order, Azipod propulsion units for about 200 vessels
Each Azipod propulsion unit takes about two months for technicians to assemble at ABB’s Vuosaari plant. Across town at ABB’s Helsinki motors, generators and drives factory, the powerful synchronous motors at the system’s core take shape over six months.
COOPERATION AMONG STAKEHOLDERS
The major driver for marine engine designers is bringing engines into compliance with emissions requirements while keeping fuel consumption and maintenance costs under control.
A new pressurized EGR (exhaust gas recovery) economizer from Alfa Laval shows how Scandinavian maritime innovation often results from a cooperation between suppliers, university departments and shipowners. It also illustrates that, for some ships, EGR may be a better means of coming into compliance with new NOx limits than the better known SCR (selective catalytic reduction).
In a project supported by the Danish Energy-Technological Development and Demonstration Program (EUDP) and developed in cooperation with Aalborg University, the EGR economizer has been rigorously tested aboard the containership Maersk Cardiff.
“As a front-runner in the pursuit of green technologies, we were keen to see what the Aalborg EGR-HPE could do,” says Ole Christensen, Senior Machinery Specialist at A.P. Moller-Maersk. “But while we were enthusiastic about the boiler’s potential, we were also somewhat uncertain as how it would handle the physical realities of EGR. The temperatures are twice as high as those of traditional waste heat recovery, and the gas pressures are far greater.”
Those concerns disappeared when the boiler was brought online with the Maersk Cardiff’s two-stroke MAN B&W 6S80ME-C9 engine in November 2014. “Not only did the boiler survive,” says Christensen, “[but also] the results we have seen during testing are very promising.”
“EGR provides Tier III NOx compliance with a very compact footprint, but compliance itself is only part of the full potential,” says John Pedersen, Business Manager, Boilers, Combustion & Heaters at Alfa Laval. “Working closely with MAN Diesel & Turbo to optimize the EGR technology, we saw additional opportunities through our expertise in marine boilers.”
In the EGR process, around 30% of the exhaust gas is directed back into the engine, which reduces the combustion temperature and thus the production of NOx. Since only the remaining 70% of the gas reaches the traditional exhaust gas boiler after the turbocharger, waste heat recovery is reduced by 30% as well.
The Aalborg EGR-HPE is a revolutionary new economizer enclosed in a pressure casing that is placed in-line ahead of the pre-scrubber sprayers in the EGR circuit.
“By moving the break point for waste heat recovery from a medium engine load down to a low load, the Aalborg EGR-HPE enables even slower steaming,” says Pedersen. “That means fuel savings that quickly pay back the economizer, offset the EGR investment and lower CO2 emissions on top of the NOx reduction.”
Positioned ahead of the pre-scrubber spray jets, the Aalborg EGR-HPE has access to much higher temperatures than traditional exhaust gas boilers. It is integrated with the conventional waste heat recovery after the turbocharger by its steam drum, which is shared with the traditional exhaust gas boiler. With the output of the traditional economizer feeding into the shared drum, the Aalborg EGR-HPE produces extremely high-quality steam with a temperature of just above 400°C, bringing the waste heat recovery system to a much higher level of efficiency.
Using the Aalborg EGR-HPE in an integrated system allows waste heat recovery to occur at lower main engine loads than possible with a traditional waste heat recovery system in Tier III operation. This creates the possibility of even slower steaming.
“The EGR economizer makes waste heat recovery beneficial at far lower engine loads, down to around 30%” says Pedersen. “This means that vessels can steam even slower, with huge fuel savings as a result.”
DUAL FUEL
B&W in MAN-B&W stands for Burmeister & Wain and the Burmeister & Wain shipyard in Copenhagen built the Selandia, the world’s first successful diesel-powered oceangoing ship. That was in 1912.
More than a century later MAN Diesel & Turbo in Copenhagen is still on the cutting edge of diesel innovation.
One beneficiary of this is TOTE Maritime which opted for MAN Diesel & Turbo dual fuel technology for its two new Marlin Class, Jones Act containerships. Both of these ships have been delivered for operation between the U.S. and Puerto Rico, burning LNG as fuel and thereby meeting all U.S. SECA emissions requirement. Each is powered by the world’s first dual-fuel slow-speed engine, an MAN-B&W 8L70ME-GI, built in Korea by licensee Doosan Engine.
The technology in the ME-GI engines wasn’t just pulled out of a hat. It is a natural development of the MAN B&W low speed electronically controlled ME family of engines. The first testing of the GI principles was carried out in 1987 and MAN Diesel
& Turbo introduced its first two-stroke ME-GI dual fuel engine series in 2011, adding the ME-LGI engine series (which can burn liquid fuels such as methanol and ethanol) in 2013.
In theory, any ME engine can be converted into an ME-GI engine, but to be recognized by a classification society as “LNG ready” an ME engine equipped newbuild will have to be designed with provision for such things as the necessary LNG fuel tanks, piping and other ancillaries.
MEDIUM SPEEDS, TOO
LNG fueling has also proved an attraction for many operators of vessels with medium speed diesels who have to operate in emissions control area.
That trend sees Wärtsilä set to deliver the 100th Wärtsilä 34DF dual-fuel marine engine from the factory in early 2016. It is part of an order for three new large escort tugs under construction for Norwegian operator Østensjø Rederi by Spanish shipbuilder Astilleros Gondan. The tugs will operate at Statoil’s Melkøya terminal near Hammerfest in Norway.
“These 100 engines do not include those delivered for land-based energy generation applications,” says Lars Anderson, Vice President, Wärtsilä Marine Solutions.
“Within its power range, the Wärtsilä 34DF has become the workhorse of the marine industry, thanks to its superior reliability and lower operating costs. It is a highly efficient engine that is also making a notable contribution to environmental compliance,”
The Wärtsilä 34DF dual-fuel engine was upgraded in 2013 with a higher MCR (maximum continuous rating) and better efficiency than its earlier version, the first of which was delivered in 2010. The upgraded version has a power output range from 3,000 to 10,000 kW at 500 kW per cylinder.
ELIMINATE THE ENGINE?
Of course, if you can eliminate the engine and switch to battery power, that gets rid of emissions issues entirely. One area where this could be possible is in certain short range ferry operations and we have already noted the E-ferry way project under way in Denmark at Søby Værft AS.
Wärtsilä, too, is eyeing this niche. In January it launched a concept for a series of zero or low emission shuttle ferries. The concept has been developed in line with new Norwegian environmental regulations for ferries, and Wärtsilä says this regulatory trend is also evident in other countries.
The ferries are designed to run entirely on batteries or in a battery-engine hybrid configuration where the fuel options are liquefied natural gas (LNG) or biofuel.
In plug-in operation, the fuel consumption is reduced by 100 percent compared to conventional installations, and all local emissions are completely eliminated. With the plug-in hybrid configuration, emissions are reduced by up to 50 percent.
The concept features Wärtsilä’s new wireless inductive charging system, which offers major benefits for typical shuttle ferry operations involving 20,000 or more departures a year because of its time and energy savings. The system eliminates physical cable connections, thus reducing wear and tear and enabling charging to begin immediately when the vessel arrives at quay.
Wärtsilä has now signed an agreement with Cavotec SA to jointly develop a combined induction charging and automatic mooring concept. It would incorporate Wärtsilä’s wireless induction power transfer into a vacuum-based automated mooring technology in which remote controlled vacuum pads recessed into, or mounted on the quayside, moor and release vessels in seconds.
FILTER PROMISES TO CUT NOX
The Exilator, an environmental filter for smaller ships, able to reduce both sulfur, carbon monoxide, NOx and noise, has been successfully tested on a Danish Maritime Authority ship. The technology has been testing over a 12-month project phase followed by a three-month practical test of the concept on the Danish Maritime Authority’s ship Poul Løwenørn. The filter’s performance has been documented by the Danish Technological Institute, and the installation and mounting of the filter has been approved by LR.
The filter has been designed for ships with engines of up to 6 MW. Current regulations don’t require the cleaning of exhaust gas from smaller ships if they already sail on marine diesel with a maximum sulfur content of 0.1%. Still, developer Exilator ApS
believes that there is already a market for the filter, as it reduces soot pollution and NOx on the ship itself and also cuts engine noise considerably — particularly attractive in the yachting sector, or expedition vessels sailing in very sensitive nature areas.
According to the test from the Danish Technological Institute, the filter reduces soot particle emissions by 99,1%, carbon monoxide by 98% and NOx by 11%. Though those tests didn’t cover the filter’s noise reduction properties but the company expects a noise reduction up to 35 dB, including low frequency noise.
Financing for development and testing was secured through the Danish Growth Fund and investment & development company CapNova.
The filter works by catalytically incinerated the soot in the exhaust as soon the ship’s engines reach exhaust temperatures above 325 degrees C. Ash is accumulated in the filter, which means that the filters must be cleaned after about 5,000 operational hours, as part of the recycling process.
The filter requires that the ship uses marine gas oil with a maximum sulfur content of 0.1%. According the test, the filter improves the ship’s fuel consumption by around 1%.
The exhaust gas, after passing through the turbo charger, goes to a muffler that removes the deep resonance. Then comes the particle filter, which also serves as an oxidation catalyst, where the soot is captured and burned – and finally the gas is led through a reducing catalyst, which minimizes NOx and NO2, before being emitted into the atmosphere.
Development is now underway in a collaboration with DTU, the Technological Institute and an engine manufacturer aimed at increasing the filter’s NOx reduction from 11% to 40% in phase 1, and to 80% in the subsequent phase 2. When this is achieved, the filter will enable compliance with IMO Tier III NOx limits.
SCRUBBERS
Shipowners face no shortage of options if they decide to use exhaust gas scrubbers to cut sulfur emissions. Recent customers for Alfa Laval’s PureSOx exhaust gas cleaning systems include Buss Shipping, which is retrofitting hybrid PureSOx systems on two 1,025 TEU container feeder ships that operate exclusively in Emission Control Areas (ECAs). Since they frequent the low-alkalinity waters between Rotterdam and St. Petersburg, as well as ports like Hamburg with zero-discharge requirements, a scrubber with closed-loop mode was a necessity.
Each ship will receive a hybrid PureSOx system with multiple inlets, connecting the main engine and two auxiliary engines to one U-design scrubber. In contrast to earlier systems with multiple inlets, the inlets will now lead into a single scrubber jet section – an advance in construction that will make the scrubber even more compact.
“The PureSOx solution was well engineered and allowed a sophisticated integration of the scrubber system into our container feeder ships,” says Christoph Meier, Project Manager, Buss Shipping. “The custom construction let us avoid major modifications inside the vessel, which together with the pre-outfitting gave us a short installation time. All those factors contributed to a competitive price.”
Though there’s no doubt that scrubbers work, they also involve a substantial investment. That led Finland’s family-owned Langh Ship to develop a scrubber of its own, the decision was made a little easier by the fact that another family-owned company has 40 years’ experience in cleaning washing waters.
The resulting product was successfully tested over an extended period on one of Langth’s own ships, the M/S Laura, and received final class approval from GL in August 2014. All of Langh’s five vessels have now been fitted with the scrubber and last year a hybrid version was installed on Bore Shipping’s M/V Bore Song.
“It has lived up to our expectations: minimum sludge handling, very clean outgoing water and in that respect minimum impact on the environment,” said Jörgen Mansnerus, VP, Marine Management at Bore Ltd.
Scrubbers could become less expensive as the result of a pilot project developed by Norwegian University of Science and Technology (NTNU) researchers Carlos Dorao and Maria Fernandino.
Called the Lynx Separator, the technology now being examined for possible use in marine exhaust gas scrubbers was originally developed for use in the natural gas industry and involves using a steel sponge along with centrifugal force to remove the fluid from a gas stream, offering a brand new solution for the gas industry.
In the Lynx Separator, wet gas flows through the separator. A tubular metal sponge spins rapidly so the liquid is separated from the gas and thrown to the side and down, allowing dry gas to stream up to where it’s needed.
The Research Council of Norway’s Innovation Program MAROFF (Maritime activities and offshore operations) has now funded a pilot project to examine the possibility of applying the separator technology to cleaning ships’ exhaust emissions from ships andetheoretical calculations and testing show promising results
BALLAST WATER MANAGEMENT SYSTEMS
Another major focus of compliance concern for shipowners is, of course, ballast water management. Needless to say, most of the major players in the Scandinavian marine equipment sectors have horses in this race. It’s just to soon to pick any winners given the fact that no system has yet gained full U.S. Type Approval.
As this was written, Norway’s Optimarin was claiming to be on the brink of the coveted approval and was pleased when the U.S. Coast Guard told manufacturers of ultraviolet (UV) based BWMS that it will not accept the Most Probable Number (MPN) testing method in its approval process. The MPN methodology evaluates organisms on the basis of “viable/unviable,” with most UV systems depositing “unviable” organisms back into the water – meaning they are still alive but cannot reproduce. The USCG said that the FDA/CMFDA test, which judges life forms as “living/dead,” must be the standard for approval.
Optimarin says the decision is good news.
The Coast Guard has told UV system manufacturers that it will not accept the Most Probable Number (MPN) testing method in its approval process. The MPN methodology evaluates organisms on the basis of “viable/unviable,” with most UV systems depositing “unviable” organisms back into the water – meaning they are still alive but cannot reproduce.
“This is a clear indication to the industry that USCG wants absolute certainty with regard to standards – they do not want living organisms deposited in their territory,” comments Tore Andersen, Optimarin’s CEO. “MPN is acceptable for IMO, but that won’t be any consolation to shipowners with global fleets that want the flexibility of sailing in and out of U.S. waters.”
He says that Optimarin, which has over 20 years of industry experience and installed the world’s first commercial BWT system in 2000, is the only UV manufacturer that is currently within “touching distance” of USCG approval.
Its technology successfully satisied the FDA/CFMDA criteria during testing last year. Further tests in other water salinities are scheduled for spring 2016, after which point approval is expected later this year.
Andersen says the system’s power is the key to its efficacy. “Each of our system lamps has a 35 kW capacity, which is huge for a UV system. That power instantly kills invasive organisms and that’s exactly what USCG wants to see,” he says
MARCH 10, 2016 — The world’s largest cruise thus far, the 5,497 passenger Harmony of the Seas, departed shipbuilder STX France’s Saint-Nazaire, France, shipyard today assisted by six tugs and headed for
MARCH 4, 2016 — Eastern Shipbuilding Group, Inc, Panama City, FL, recently launched the Zyana K. The vessel is the second in series of four Robert Allan, Ltd. (RAL) designed Z-Tech 2400
MARCH 3, 2016 — GE’s Marine Solutions will provide the LM2500+G4 gas turbine that will power the Italian Navy’s new Pattugliatori Polivalenti d’Altura (PPA) multipurpose offshore patrol ships. The ships’ hybrid electric
FEBRUARY 23, 2016—Beacon Finland, Rauma, Finland, recently appointed Rio Marine, Inc., Houston, TX, as its exclusive company to service its JAK-ATB coupling systems in the U.S. The JAK ATB coupling system is
FEBRUARY 22, 2016 — Fincantieri Marine Group reports that 14 Great Lakes vessels are currently undergoing winter repairs at its Fincantieri Bay Shipbuilding division in Sturgeon Bay, WI. The vessels range in
JANUARY 29, 2016 — Recently installed aboard the R/V Sikuliaq, Allied Marine Crane’s innovatively redesigned A-Frame crane is designed to drastically improves the safety and capability of the marine research industry, and
JANUARY 19, 2016 — Eastern Shipbuilding Group, Inc., Panama City, FL, recently launched the M/V Harvey Stone (Hull 234) for Harvey Gulf International Marine, LLC of New Orleans, LA, in a ceremony
The International Workboat Show in New Orleans, LA, offers the marine industry an ideal time to not only assess the current state of the industry, but also an opportunity to view some of the newest technologies, products, and services. With stricter emissions regulations coming into play in 2016 and operators strongly focused on efficiency and the bottom line, this year’s show saw a number of new power and propulsion technologies unveiled. GE Marine, for example, extended its EPA Tier 4 engine series to include 16- and 12-cylinder V-models, an 8-cylinder inline model, and a 6-cylinder inline model that is currently planned for development.
GE says the engine series meets the Environmental Protection Agency’s (EPA) Tier 4 emission standards without the use of urea after-treatment, while maintaining fuel efficiency and service intervals. In addition, the engines have a faster response time to load steps, and a Maximum Continuous Rating (MCR) that is 12 percent higher than their Tier 3 compliant predecessors.
Coastal tug and barge operator Reinauer Transportation purchased two 12V250MDC Tier 4 diesel engines for its new Articulated Tug Barge (ATB) unit under construction at Senesco Marine in Kingstown, RI. One of the engines was displayed at GE’s booth at the Workboat Show.
“We chose the new GE Marine engines because we like their robust design and component configuration,” says Christian Reinauer. “The engine closely matches the footprint of our current vessel design. This limits the amount of re-engineering while meeting Tier 4 emissions requirements without the complications of urea after-treatment.”
GE’s Marine Product Manager Rob Van Solingen says the engines offer several advantages as compared with engines that use an SCR-based emission control system.
He says that the GE Tier 4 engines are less complex, allowing ship designers to develop engine rooms that make the most efficient use of space. This reduction in complexity also translates into improved labor efficiency at shipyards.
The engines also offer space and weight savings, since there is no large SCR reactor system in the exhaust piping of each engine nor any urea tank, dosing equipment, monitoring/control systems, and related piping, and air supply system required.
“Depending on size and urea quantities, space and weight savings of the engine and complete SCR system with all components and urea tanks can save up to 75% on each when compared to the GE T4 diesel engine,” says Van Solingen.
In addition, says Van Solingen, “The EGR system is designed to not require any special maintenance between the normal scheduled overhaul intervals for our engines.”
Other U.S.-based customers Harvey Gulf International Marine and Oceaneering have also ordered 12V250MDC Tier 4 engines to meet stricter EPA emissions standards. Two 12V250MDC Tier 4 diesel engines will power Harvey Gulf’s new Robert Allen designed Multi-Purpose Field Support Vessel, currently under construction at Eastern Shipbuilding Group in Panama City, FL.
Meanwhile, Oceaneering has ordered five 12V250MDC Tier 4 diesel engines for its new Inspection, Maintenance and Repair (IMR) vessel MSV Ocean Evolution under construction at BAE Systems in Mobile, AL.
NEW ENGINE FROM MAN
Also on display at the WorkBoat Show was a new inline six-cylinder diesel engine range for workboats, ferries, fishing trawlers, and pilot boats based on the MAN D2672 diesel engine from MAN Engines. Offered in a range of outputs from 323 kW to 588 kW (440 to 800 hp), the basic six-cylinder engine has been proven in a wide range of on- and off-road machinery since it was first introduced in 2007. Its robustness and reliability in workboats has also been demonstrated in extensive field trials over several thousand hours of use in ferries, pilot boats and high-speed catamarans.
The modern common rail injection system used in the D2676, with fuel pressures up to 1,800 bar, ensures high mean pressures and optimized combustion. This increases on-board comfort due to reduced vibration and noise emissions. The inclusion of a Miller or Atkinson camshaft has helped to achieve an average 10% reduction in fuel consumption compared to the engine’s predecessors.
As part of this improvement in fuel consumption, all engines also comply with the current strict EPA emissions.
The new MAN D2676 marine diesel engines replace the predecessor models D2866 and D2876.
The new D2676 engines also offer the wide torque plateau that is characteristic for MAN marine engines. The 323 kW (440 hp) power unit provides 1,950 Nm of torque between 1,200 and 1,600 rpm for heavy operations, while the 588 kW (800 hp) high-performance model manages to generate 2,700 Nm between 1,200 and 2,100 rpm for light operations. This ensures maximum torque over a broad engine speed range at the lowest specific fuel consumption.
SCANIA MAKES IN ROADS
Scania has been making inroads in the marine propulsion sector because of its compact, proven engine platforms. Some recent installations in the U.S. Gulf of Mexico include the high-speed crewboat Fourchon Runner, which is powered by quadruple Scania 16L engines for a total of 2,400 hp.
Naiad Inflatables recently delivered the Karankawa, a twin-screw pilot vessel for the Matagorda Bay Pilots of Texas. The pilot boat has two Scania DI13 77M main engines, with Twin Disc MGX-5114A gears and ZF controls. It employs shaft propulsion with driveline components from H&H and Michigan Wheel propellers. The pilot boat has a top speed is 33 knots.
At the Workboat Show, Scania showcased its Tier 3 platform, including its 16-liter V8 and 13 liter inline engines.
Scania engines are all based on Scania’s new modular engine platform—well proven in the company’s truck and bus engines. Scania V8 engines are engineered to produce high power, while maintaining a size that is compatible for auxiliary equipment. The V design reduces the overall length of the engine and ancillaries can be effectively accommodated inside the footprint of the engine.
The output ratings for Scania’s newest Tier 3 version of the 16-liter marine propulsion engine range from 550 to 900 hp, with outputs between 550 to 1,000 hp available for use in international and exempt markets.
For auxiliary applications, the range for EPA Tier 3 is 468 kW – 553 kW, and the current range will continue to be offered between 430 kW – 596 kW for international and exempt markets. Scania also expects to see an increase in the output ratings of V8 engines used for keel-cooled applications.
The output ratings for Scania’s newest Tier 3 version of the 13-liter inline marine propulsion engine range from 250 – 675 hp, with outputs up to 750 hp available for use in international and exempt markets. For auxiliary applications the range for EPA Tier 3 is 269 kW – 426 kW.
Scania’s centrifugal oil cleaner effectively removes small particles from the lubrication oil, while reducing the size of the replaceable filter cartridge. The Scania saver ring, placed at the top of each cylinder liner, reduces carbon deposits on the edge of the piston crown and reduces cylinder liner wear.
In spite of higher performance and tighter emission levels, Scania has been able to increase maintenance and oil change intervals by 25% (now 500 hours) in comparison to its predecessor.
NEW CONCEPT: TWIN FINS
During a presentation for the trade press at the Workboat Show, Caterpillar highlighted the development of its Twin Fin Propulsion Systems. The initial Twin Fin Propulsion System was retrofitted on the seismic vessel Polarcus Naila at Shipdock in Amsterdam in March 2014.
“In the seismic business, seismic assets or the vessel is a huge workhorse,” says Peter Zickerman, Polarcus Executive Vice President. “About 85 percent of its lifetime, the vessel is under constant tow in various weather conditions. It is imperative that the reliability of the vessel and its propulsion system are top notch.”
The Twin Fin is designed for vessels that operate on a diesel-electric propulsion system. With thrusters, vessels can have more cargo capacity. With conventional propellers, operators benefit from added reliability and safety. Twin Fin offers the advantages of both. It offers higher thrust performance, reduced fuel consumption, and a better emissions profile.
According to Mattias Hansson, naval architect and sales manager at Caterpillar Propulsion, development of the Twin Fin Propulsion Systems started with the company’s partners in the third quarter of 2012 and a patent application was filed in the first half of 2013. Hansson points out that the Twin Fin Propulsion System also incorporates some green aspects, including, a water-lubricated stern tube, instead of an oil-lubricated system.
For the retrofit, the twin fins were prefabricated in about 15 days and readied for the Polarcus when she arrived at the shipyard.
“This new system provides an excellent course keeping stability for the ship—important for a scientific ship like this,” says Henning Kuhlmann, Managing Director, Becker Marine Systems. Becker Marine Systems supplied highly efficient flat rudders for the installation of the Twin Fins.
The payback period for the system is about three years based on fuel consumption savings, efficiency gains, improves environmental footprint, and improves reliability when operating in remote areas.
In the coastal market, Caterpillar is supplying two harbor tugs being built for Harley Marine Services, Seattle, WA, at Diversified Marine, Inc., Portland, OR.
Each of the Harley Marine tugs will be outfitted with Cat 3516 main engines—each rated at 2,575 hp at 1,600 rev/min—and two MTA 524-T azimuthing thrusters. The thrusters will have 95.5 in. diameter fixed-pitch propellers.
Cat Propulsion’s Emil Cerdier says the MTA-T thrusters deliver “excellence of economy and performance to the tug market.” The tugs will be delivered by Diversified Marine in 2017.
Z-DRIVES GO INLAND
While Z-drives are fairly commonplace in the tug market, they are a relatively new phenomena in the inland towboat market. While some were installed as early as the 1980s, Z-drives got a major boost in 2006, when Bill Stegbauer and Ed Shearer began exploring the use of alternative propulsion, including Z-drives in inland towboats. Stegbauer, then President of Southern Towing Co., eventually opted for a design that would use Z–drives in a series of 3,200 hp towboats.
There are now about two dozen towboats operating with Z-drives and more are under construction. One of the latest series of three 6,300 hp towboats designed by The Shearer Group that are being built at C&C Marine and Repair, Belle Chasse, LA, for SCF Marine Inc. As you might guess, Ed Shearer is the President of The Shearer Group.
The towboats will each have three Cummins QSK60-M diesel engines coupled to three Steerprop SP-25D z-drives. Cummins Mid-South is supplying the engines, while Karl Senner, LLC, Kenner, LA, is supplying the Z-drives.
The Z-drives were selected only after a through analysis. “We worked closely with the both the owner and the naval architect, but at the end of the day, the decision was up to the owner, SCF,” says Karl Senner. “Tim Power and Myron McDonough were very diligent in the selection process, and we very much appreciate the in-depth approach and attention to detail. We pride ourselves in offering robust products and superior support, factors that are critical while operating in the demanding environment of the inland waterways. Steerprop units are designed for the longest time between overhauls on the market. We have also been supporting inland operators since our company’s inception in 1967. We are very excited about our relationship with SCF and we know it will continue for a long time to come.”
Steerprop SP25D Z-drives are designed for operating in harsh environments. These specific drive units were selected and configured similar to that of ice-class applications. Ice class design is Steerprop’s forte, having designed and supplied Z-drives on board three of the world’s largest mechanical Z-drive ice breakers build to date.
These will be the first inland towboats in the U.S equipped with Steerprop Z-drives. “The inland waterways have been a major focus of our business since 1967 for Reintjes gearboxes,” says Senner. “We pride ourselves in knowing what it takes to support the high demands of our inland customers, from sizing the appropriate equipment, to stocking spare parts, and providing quick service turnarounds. We are a family-owned and -operated company, flexible to respond to customer needs quickly and effectively.”
“We are in discussions with multiple other inland projects, but not at liberty to discuss them at this point in time.”
Z-drives have begun to catch on with inland transportation operators because of the safety, operational efficiencies and fuel savings they offer. As operators of harbor tugs have long been aware, the Z-drive can deliver full thrust in any direction almost instantly, where as the conventional rudder set aft of the propeller and even the flanking rudders set ahead of the rudder as is the practice on many inland river towboats, will sacrifice time and power by the inefficient nature of the conventional drive and rudder system.
Due to the greatly improved maneuverability with Z-drives, tows do not need to slow down in turns and bends in the river. Trip times are reduced and require a lot less fuel. A study conducted by The Shearer Group, Inc. last year showed an average of 28% fuel savings and 11% trip time savings during a set of controlled experiments with unit tows when using Z-Drives instead of conventional shafts and rudders.
SCF Marine, Inc., St. Louis, MO, is part of SEACOR’s Inland River Services group. SCF Marine operates a fleet of hopper barges along the U.S. Inland River Waterways and South America, transporting agricultural, industrial, and project cargoes.
Thrustmaster of Texas, Inc., Houston, TX, says towboats with Z-drives are not significantly more expensive than conventional towboats. The initial cost of the Z-Drives is significantly offset by reduced construction costs and installation man-hours. Shipyards have reported that the cost of building Z-drive boats is actually less than building conventional boats.
One of the latest applications of Z-drive propulsion is in a fleeting boat by Carline Companies. Carline recently added the 68 by 34-foot towboat USS Cairo for barge fleeting on the lower Mississippi.
Designed by Christian Townsend of CT Marine and built by Raymond & Associates, the USS Cairo is fitted with two six-cylinder Tier 3 compliant Cummins QSK19 main engines turning Thrustmaster TH750MZ Z-drives with 57-inch propellers.
According to Thrustmaster of Texas, a Z-drive replaces the propeller, shaft, stern tube, marine gear, rudder and steering gear all with a single unit. Z-drive azimuthing thrusters provide maximum thrust in any direction, independent of vessel speed, offering superior pinpoint maneuverability under all conditions. Rudders are completely eliminated. Rudder drag no longer exists. All of this can be done with a lot less power. A 1,500 hp Z-drive boat can replace a 2,000 hp conventional towboat and a 3,000 hp Z-drive boat can replace a 4,000 hp conventional towboat.
