It is a well known fact that you just did not mention pigs or rabits on board a trawler, why? No idea, but you just do not. Likewise if you by chance neet a clergyman as you are going down to sail you must go home & start out again, or at the very least turn round three times, of course you must never wear green, or wash clothes on sailing day, or burn fish bones, . And of course, as everyone in the fishing community knows, anyone born with a caul will never drown.
All these "facts" were known, and acted upon at least up to the late 70s, in Fleetwood. Of course if you asked them why, you'd never get a straight answer, the usual reply being "'cause you just [don't] do that!"       Sailor Ron