Modification of the bow thruster’s generator set automation system

The m/f Gryf had been purchased by the Polish ship-owner, Unity Line, as an answer to growing demand for transport services between Poland and the Scandinavian states.


Due to unique sailing conditions on the Baltic equipping the ferry with an additional bow thruster and increasing its maneuverability proved indispensable. Previous to handing over the vessel for exploitation a supplementary rudder had been installed along with an automation system and a completely new 1 MVA generating set.

rozdzielnica volvo
rozdzielnica front

Originally this new installation had been designed to provide power only to the bow thruster during the short periods of time while entering and leaving port. At a certain moment an idea of using the generator for other purposes, than only powering the bow thruster, came to mind. The concept was to connect the generating set to the ship’s power plant as an integral part of the whole system. MAREL SERVICE took on the challenge of designing and modifying the system.

For this purpose we had to gather all necessary information regarding the whole elaborate network of devices comprised of three auxiliary motors, a shaft generator and an emergency generator, all equal to a couple of megawatts of power. Having done some quintessential calculations, which took into consideration the effect of the new energy source on the existing power distribution system, MAREL SERVICE went on to develop a modification plan which would make possible the use of the bow thruster generator as a power source to supply power to all receivers on board the vessel.

Volvo_Penta generator

After lengthy negotiations with the ship-owner, the crew and the marine classification agency responsible for the evaluation of safety on board the ferry, MAREL SERVICE had finally received the “green light”. The task at hand was not facile. One had to keep in mind the many other systems (apart from the bow thruster) working in parallel with the genset – i.e. the fire extinguishing system. The whole project had to take into consideration the fact that the generator had to be kept on standby at all times in order to be able to supply power to those systems regardless of the crew’s activities or the load put on the generator.

Worth mentioning is also the time regime in which the works had been performed. MAREL SERVICE had only two weeks appointed for installation of the altogether new automation distribution board – replacing the old system and additionally expanding it by a new function. All final works like testing and activation were carried out in between the cruises, without disrupting the everyday exploitation of the vessel, and most importantly without any detriment to safety of the crew and passengers.

volvo penta

Eventually, despite the difficulties the modification had proved a full success. MAREL SERVICE had modified the ship’s power plant, integrating the huge, new power source with the already existing power grid. The system allows switching between power sources at any given moment and without time-outs. Moreover, the system is on stand-by at all times, ready to supply power to emergency receivers, therefore upgrading the safety as well as functionality of the entire system.