Marine Log


July 31, 2006

Multraship orders Carousel tugs

Multraship Towage & Salvage of the Netherlands has ordered two innovative combi-tugs from Malaysian shipbuilder Nautica Nova Shipbuilding & Engineering (NNSE),

They incorporate the unique Carousel towing system.

The first of the two eighty-tonne static bollard pull tugs is due for delivery at the end of 2007, the second,about three months later.

The Carousel system enables the towing wire to rotate 360 degrees around the tug, improving braking and steering power while reducing costs. It consists of a large rotating ring and hydraulic winch, fitted on the raised main deck level.

The system has been proven to produce superior tug behavior and guarantees the safety of the vessel in even the most severe braking pull situations. The dynamic bollard pull of the vessels will be around 160 tonnes.

The Carousel ring allows the towing hook or winch to rotate freely without limitations. In addition, towing operations can be changed from bow to stern use or vice versa.

The Carousel is based on the same principle as a radial hook, but extended to the full ship's width.

This design offers improved stability and an increase in hydrodynamic forces to alleviate the risk of capsizing. It is claimed that, due to the generous safety margin in the stability range, capsizing due to towline force is statistically no longer feasible for a Carousel tug.

The Carousel can be placed immediately above the center of lateral resistance to maximize the towline forces and minimize the need for steering propulsion on the tug.

The Carousel can be applied to any tug design.

Multraship director Leendert Muller says, "We are very excited about the possibilities which these tugs offer to revolutionize the towage and salvage industry. Multraship is an innovative, forward-thinking company, and in NNSE we have identified the ideal partner to cooperate with to produce a new generation of tug."

NNSE is an established shipyard in Penang, which began life as a fast military patrol boat repairer in the 1970s. In the 1990s, it expanded its facilities to accommodate overseas orders, and later diversified into the oil and gas industry. It has recently been involved in a contract to build two Singapore-flagged anchor-handling tugs classed by Lloyd's Register.

The Multraship Carousel combi-tugs are designed for unrestricted harbor towage, escort services and seagoing towage.

Each will have two General Electric 7FDM 12-cyliner diesel engines of 2,290 kW at 1,050 rpm each. The design incorporates a large conventional ducted propeller at the stern and an azimuthing bow-thruster, resulting in high efficiency with exceptional maneuverability in continuous ahead or astern operation, both free sailing and towing.

The overall length of the vessels will be 33 m, and the moulded breadth 12 m.

Maximum speed will be at least thirteen knots, with a minimum continuous bollard pull ahead of 80 tonnes.

The tugs are designed by Netherlands-based Worldwise Marine Engineering B.V. and Technisch Bureau Gommers, in co-operation with the designer of the Carousel system, the Rotterdam-based company Novatug B.V.