Extensive model testing has taken place using single and twin-screw concept models and the scale model of Multratug 12 a small single screw 'Combi' tug from the Multraship fleet. Results of that testing have been both highly successful and encouraging.

Although the various conceptual designs have produced good results, the application of a Carrousel towing system to a new or existing single screw tug is seen as a particularly attractive proposition.

Model testing has been followed by the conversion of Multratug 12 to enable full scale testing to proceed. A Carrousel towing system has been installed at a shipyard in Breskens, Holland, and at the time of writing trials had just started.

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. A fully azimuthing, retractable, thruster forward is driven by a separate 450bhp diesel. In its original form the vessel had a static bollard pull of 21 tonnes. The relatively low freeboard of this vessel limits the maximum dynamic forces that can be achieved but the choice of tug is seen as a good compromise and towline forces of over 60 tonnes are expected when towing in the indirect mode on a moving ship.

Considerable interest has been created by the Carrousel Towing System and the results of trials will be eagerly awaited by many in the towage industry. There are a number of obvious technical problems to be addressed, among them the desirability of being able to utilise a towing winch and not just a quick release hook.

Mampaey are adamant that solutions are already in hand.

There are also the matters of safety on deck and access to the accommodation but these are early days for what is surely the first major innovation in towing gear principles for several decades.