When Fishing Vessels Change Over to Heavy Fuel Oil

Nowadays, most fishing vessels operate on diesel oil, which can be treated more easily on board than highly viscous heavy fuel oil. However, the tremendous increase in prices, particularly for diesel oils, has triggered off a re-thinking process that is causing many fishing vessel operators to consider to what extent changing over from diesel oil to less expensive heavy fuel oil might be economic. In addition to the cost-benefit calculation, the technical feasibility of such a move is also very important. Unlike diesel oil, heavy fuel oil has to be specially processed for combustion in the engine. This is the task of the booster unit, which is responsible for adjusting injection pressure and injection viscosity.
Booster units are considered to be part of essential equipment, and have to be fully functional at all times. If they fail, the engine is shut down and this means that the vessel is incapable of manoeuvring. For this reason, a redundant arrangement is used for pumps and preheaters of the booster unit, resulting in an increased space requirement.

On diesel-operated vessels, the amount of space available for subsequent installation is frequently very restricted, as subsequent conversion to heavy fuel oil was not planned when the vessels were built. A further problem is the need to position the booster unit within the hull of the vessel. To make this easier, each booster unit is broken down into several small modules that are placed appropriately in the space available. This allows short delivery times, sometimes of only a few weeks, to be achieved.