How many times did we surprise? Many and in that moment, when fuel goes out from the entrance hole, our regret is double: for the sea where it spills, even if the waters are those of a harbour, and for our deck, mooring ropes and gunwale wood.
A little of caution, a slower fuel supply, a gurgle near the entrance, the skill to find the air with some nuked fuel going out when the tank is almost full, a little of fuel going out from the overflow. All useful precautions but the snag is always lurking.
In order to prevent fuel from impregnating teck or deck, every time we fuel, we can scatter the entire zone with some fresh water before, of course, opening the fuel tank cap.
This way, the eventual fuel would slide on the water layer it meets around the entrance hole by minimising the contact with the deck.
Of course, especially in summer, water must be poured some minutes before fuelling otherwise, by evaporating, it wouldn’t produce any effects.