I had my gas tank stolen once in St. Martin - I made it halfway back from the Marigot dock to my boat when the engine died and I couldn't restart it... it took me a while to realize why! Rowing a dinghy against 15Kt of wind is no fun And the next day it turned out that all the smaller tanks were sold out and all they had were $100 tanks (that was the empty price - fuel costs extra).

Ever since then my locking cable has always been looped around the 2 outboard tightening handles and through the gas tank handle.