I dont know how I know this and I dont even know if it is correct, however the reason for not taking a banana on a boat stems from the Carribean. Apparently during the old days when boats were used to transport items from island to island the boats carrying bananas were the ones that come to grief. The reason being is that because the bananas were perishable they would take more risks and go out in bad weather just to get the load to the next island and get paid. So the theory rose that working on a banana transport boat bought bad luck. I think it just got bigger from there to the fact
