In fact it directly says that: To avoid petrol leaking into the boat from fuel containers, they must be stowed in accordance with Standards 7.2 through to 7.8, e.g. in a fire resistant drained locker Also this comment is made in the part 5 regs: One boat owner had a nasty shock on a hot and sunny day. The petrol stored in containers on his deck was left in direct sunlight on one very hot and sunny day while the owner visited a local attraction. On his return, the boater decided to refuel his small outboard-engined boat, but forgot that vapours from the fuel would build up under pressure, because of the heat affecting the containers. When he opened the lid, petrol vapour escaped under high pressure and was ignited by what is believed to have been a discarded cigarette. The boater suffered significant burns to his arms as a result. [5.3]