The Carrousel, a revolutionary patented towing connection, is one of the most radical technical developments to be offered to the industry for many years. It was conceived by Dr Markus van der Laan, of Netherlands based IMC, as a joint project with towing gear manufacturer Mampaey, and tug-owner Multraship Towage & Salvage of Terneuzen.

The concept involves fitting a completely circular track known as a 'Carrousel' to provide a completely circular path around the vessel's superstructure on which the towing connection is free to travel to any position around the tug.

This enables the 'towing point' to be positioned near the tug's 'Centre of Lateral Resistance' giving a large margin of safety and stability. The tug can therefore tow in any direction and exert very high towline forces when working in the indirect towing mode, in almost complete safety.

After extensive model testing the tug Multratug 12 , a vessel from the Multraship fleet, was converted to carry out testing as a full sized prototype. A Carrousel towing system was installed aboard the tug during a conversion requiring extensive modification to the superstructure and deck fittings.

Multratug 12 is a single screw vessel of 28.5m in length, with a beam of 6.6m, powered by a main engine of 900bhp.

An existing fully azimuthing, retractable, bow thruster is driven by a separate 450bhp diesel. In its original form the vessel has a static bollard pull of 21 tonnes.

After consultation with the Dutch Shipping Inspectorate and other safety related bodies Multratug 12 was put to work, shiphandling in the Terneuzen area and in the Terneuzen/Ghent canal.

Multraship's Managing Director Mr Kees Muller has reported that: 'The results achieved with the Multratug 12 have been nothing short of phenomenal and represent an absolute revolution in shiphandling.

I am proud to be the operator of this 'Carrousel' prototype'.

Multratug 12 has proved to be simple, safe, and economical to operate and when attending ships underway at speeds of up to 8 knots has produced steering and stopping forces in the order of 104 tonnes. These forces far exceed the tug's static bollard pull and are achieved by using the hydrodynamic forces generated during indirect towing. The position of the towing point enables the tug to operate to its maximum advantage, in great safety.

In recent weeks Multraship Towage & Salvage have purchased the sister tugs to Multratug 12 , the Petronella J Goekoop and Hendrik P Goedkoop . Originating from the Amsterdam fleet of Svitzer Wijsmuller, both are single screw 'Combi tugs' of 900 bhp fitted with Aquamaster retractable azimuthing bow thrusters of 500bhp. They have been renamed Multratug 14 and 15 respectively both tugs will be fitted with a Carrousel.

Multraship also have plans to build a new vessel designed around the new towing system. It will be a relatively simple, single screw 'Combi-tug' design, equipped with a thruster forward, and will have a static bollard pull of about 80 tonnes. Such a vessel will be cheaper to build than a modern omni-directional shiphandling tug with sophisticated propulsion systems and is expected to achieve line pulls approaching 200 tonnes when operating in the indirect mode.

At present the Multratug 12 operates using a conventional quick-release towing hook mounted on the Carrousel track.

In any future development the addition of a towing winch is crucial. With this in mind Mampaey has a purpose designed and highly innovative winch under development. The first purpose built winch for the Carrousel is likely to be available for trials very shortly.