Attempting to minimize operating costs to fishers, they sometimes decide to use the cheapest marine fuels. Their low quality adversely affects the durability of fuel injection equipment. Similarly, reduction of sulfur and aromatic hydrocarbons, increase the boiling point at normal pressure and cetane number of modern fuels leads to a significant deterioration in their tribological properties. Polish fishing vessels can be achieved by using biofuels, which is a mixture of diesel and rapeseed oil. To carry out comparative studies for diesel and biofuel engines used to power fishing vessels were needed data, specifying lubricity and calorific value of fuels used by Polish fishermen. The conclusions are based on the examination of the chosen parameters for randomly selected fuel samples from Polish suppliers or taken directly on fishing vessels