Motor boats have a wide range of engines to provide the necessary means for propulsion. The most commonly used fuel is diesel due to its inherent safety and good volume to energy conversion power. Its ability to be stored safely in relatively large volumes extends the range that boats using this fuel can go. Petrol is also widely used particularly for outboard motors with relatively short ranges in comparison to diesel engines. The safety of petrol on board a boat is understandably a concern with a significant number of fires that are caused by poor storage, leaks or spillages. There is an increasing interest and use of electric motors to power boats. The electricity being produced and stored in batteries by such means as solar and wind power. However most electric boats will also have diesel generators as a back up to provide power when insufficient sun and wind are present.