When it comes to the best gas for boats, you need to be sure you’re using fuel with the correct octane rating. This number is determined by how powerful your boat engine is, and the minimum rating varies depending on your country. In America, 87 is the most common minimum octane rating. It’s important to use fuel with a high enough octane rating to avoid damage to your boat engine. However, this doesn’t mean that you have to sacrifice performance for safety. Some machines don’t require as high of an octane rating as others, so be sure to check your owner’s manual before making a purchase.