Page 8: of Marine News Magazine (June 2012)

Rotterdam based shipping company Rotortug and ASD Ship Design have invented a revolutionary tugboat tech- nology (tugnology) to prevent towline failures from chaf- ing against a tugboats fixed towing point. The invention of Ton Kooren (Rotortug) and Arie Aalbers (ASD Ship Design), the so called azimuth friction free towing point, was unveiled last month in Barcelona, Spain. Conventional towing point designs are usually fixed bitts fitted with polished and stainless steel cladding inline contact areas guiding a towline to a towing winch. Using state of the art towing winches, towlines are winched in and out automatically by using a pre-set line force to prevent both dynamic overloads and slack wires. Synthetic towlines can easily fail due to chafing and fric- tion with increased risks for safety. Fast in-and-outgoing movements of a towline with these winches cause high temperatures, especially at the inner core of synthetic towlines. This is an even bigger issue at high outdoor temperatures. The fiction and the high result temperature cause much wear and, eventually, fail- ure of a towline connection itself. Rotortug and ASD Ship Design in cooperation with the company Ridderinkhof in Hasselt have developed a rotat- ing wheel construction to guide the towline without fric- tion. The patent on this invention is currently pending. Because synthetic towlines are generally seven times lighter compared to equivalent steel wire towlines, they are also gradually replacing steel wire towlines. A down- side to synthetic towlines, however, is their sensitivity to chafing and maximum safe working temperatures. Together with the Rotterdam based maritime service provider Kotug International and the Rotterdam pilot organization Rotortug has developed new methods to assist sea going ships. One of these methods is the so called rotoring, a method through tugs of the Rotortug type can assist objects to be towed and moored in con- fined spaces. The azimuth friction free towing point enables rotoring in heavy seas. Ridderinkhof is awarded the exclusive, initial production rights for the azimuth friction free towing point. www.asd-shipdesign.com and www.rotortug.com 8MNJune 2012TECH FILEAzimuth Friction Free Towing Point Dutch invention prevents towline failure on tugboats