For the first time, high-speed diesel engines alone are being used to power a 90-ton bollard pull harbor tug. This is a figure used to express the amount of force exerted by the tugboat. In mid-September, four tugs from the Turkish Sanmar shipyard – powered by two 2,700 kW mtu diesel engines – proved in a bollard pull test that they are among the most powerful of their kind.
In the bollard pull test, engineers set up a tension balance between the boat's tow rope and a bollard. The tug was then operated at different power levels, with the scales showing how many metric tons of power the boat was able to produce.
To date, harbor tugs with bollard pulls of over 85 metric tons have more often been fitted with medium-speed engines. “High-speed engines are much more compact than their medium-speed counterparts, and also have lower price tags,” said mtu expert Andreas Müller-Hirlinger, explaining the benefits of the engines and the trend towards high-speed engines. For the Sanmar tugs, mtu has also reduced the speed of the 16V 4000 M73L engines from 1,970 to 1,850 revolutions per minute. The result is that the powertrain does not have to be interrupted by a gearbox, allowing the engines to deliver directly to the Schottel azimuth propellers.
The tugs, almost 30 meters in length and 6 meters wide, are to be delivered to the Svitzer shipping company in October and will be used as terminal tugs in the Moroccan port of Tanger-Med.