Important features inherent in the design of these vessels are a high degree of static and dynamic stability and fuel-efficiency. Potential savings in fuel cost of between 30% and 50% are quoted by Multraship.

The Combi-tugs feature two General Electric 7FDM 12-cylinder diesel engines, each producing 2,290kW (3,111bhp) at 1,050rpm, coupled to a large single propeller via a twin input-single output gearbox. The propeller will rotate within a fixed nozzle and a single semi-balanced rudder will be fitted. Beneath the bow will be a fully azimuthing propulsion unit, driven by carden shafts from an additional power takeoff on the same gearbox.

The vessels will have an overall length of 33m and a moulded breadth 12m. Maximum speed will be at least 13 knots, with a minimum continuous bollard pull ahead of 80 tons.

Novatug, the designer of the Carousel system, was awarded the prestigious Dutch Maritime Innovation Award in 2003 for implementation of what the Dutch Transport Minister at the time described as 'the sensational new Carousel concept'. The tugs are designed by Netherlands based Worldwise Marine Engineering BV and Technisch Bureau Gommers, in cooperation with the designer of the Carousel system, the Rotterdam-based company Novatug BV.

The Carousel system enables the towing wire to rotate 3600 around the tug, improving braking and steering power while reducing costs.

The system has been proven to produce superior handling characteristics and guarantees the safety of the vessel even in the most severe braking pull situations.

The Carousel ring allows the towing hook or winch to rotate freely around the vessel. This enables towing operations to be changed from bow to stern or vice versa. The Carousel is based on the same principle as a radial hook, but extended to the full ship's width. This concept offers more stability and an increase in hydrodynamic forces to alleviate the risk of capsizing.

Multraship director Leendert Muller says, 'We are very excited about the possibilities that these tugs offer to revolutionise the towage and salvage industry.

Multraship is an innovative, forward-thinking company.'

NNSE is an established shipyard in Penang, which began life as a repair yard for fast military boats in the 1970s. 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.