An integrated Seafish research programme on fuel efficiency for fishing vessels has found that there are no discernable improvements in fuel economy when using diesel fuel additives in engines for 10 metre class vessels.
This major Seafish managed project, which is nearing its end, is investigating a range of factors that could help reduce the fuel costs for the fishing fleet, including research into environmentally friendly biofuels.
A key element of the project is testing diesel fuel additives to assess manufacturer’s claims that their use leads to a reduction in fuel consumption.
There are a range of fuel additives on the market that are designed to improve engine performance, but do so in different ways. Some are ‘ignition improvers’ whilst others work by cleaning the engine and improving efficiency. The different attributes of such additives include water removal from fuel, control of diesel sludge, improved lubrication, biocidal properties and emission/soot reduction.
Seven types of red diesel additive were tested by biofuels researchers at the University of Exeter’s Camborne School of Mines, using their engine test cell facility. The test cycles simulated the conditions found during a typical day trawl cycle of a fishing vessel operating out of Newlyn. The trials were carried out on a hi-tech test bed because it can prove difficult in real life conditions to identify improvements below 10%, given the number of variables found during fishing vessel operations.
The test cycle was established after consultation with local skippers and Seafish. The cycle simulated a day trawler steaming for 2.5 hours to the fishing grounds and then carrying out three, four-hour long trawl tows before returning to port. For each diesel additive, the computer-controlled dynamometer puts the test engine through exactly the same schedule of speeds, stresses and drag experienced by such a vessel during a typical fishing period.
A 90kW Perkins marine engine (Perkins 6.3544M) was selected for the trial because it is representative of the type of power unit generally used by 10m day-trip vessels.
During the test cycle, the fuel consumption with each of the additives was carefully monitored and recorded by a high precision fuel weigher integrated into the computer-controlled system. Then, the results were compared with a series of tests using just red diesel alone.
The results indicate that, for the Perkins engine tested, there was no significant effect of any of the additives tested on fuel consumption. In fact, it would actually cost a fisherman more to run a vessel on BS590 diesel with additives because as well as paying for the base fuel, there would be extra expenditure on the additive.
However, the project only tested for fuel consumption and did not take into account any other benefits that may be derived from additives such as a reduction in exhaust emissions or reducing wear on the engine.
Seafish is also keen to stress that if skippers are finding that additives are proving beneficial to their own fuel consumption, there is no reason why they should not continue to use them for that purpose.
Richard Caslake, Seafish project manager, said: “The rising cost of fuel is having a dramatic effect on the profitability of many sectors of the fishing fleet. The fuel cost equates to an ever increasing proportion of the gross profit of vessels. Research into fuel saving technologies will hopefully result in vessels benefiting from both reduced fuel usage and running costs. In this case it may make skippers think twice before purchasing diesel additives in the expectation that it will improve their fuel economy.”
Further investigations on other fuel saving techniques will take place over the coming months. These will examine the potential benefits of using both electromagnets and permanent magnets as a means of improving fuel efficiency. A vortex exhaust system that has been reported to improve engine performance in fishing vessels will also be tested, as will specialist types of lube oil.
