The superstition of bananas aboard started in the tuna fleet, when an new boat sank , every thing was the same but a stack of bananas was aboard, which got the blame. Being fishermen superstition comes with the job;Just like whistling in the wheel house bring up the wind, or wearing black etc...
All most everything that have been done repeat if it brings you luck in a good haul, and any thing that you did or fail to do that cause you to have a bad trip becomes the reason why you came back to port with a bad catch or what ever.