Thirteen is rarely a lucky number to fishermen; they will often refer to the number as "12 plus 1". Fridays are also rife with unluckiness. Fishermen who choose to leave on Fridays may attempt to counteract the unluckiness by knocking on wood as they head to sea or even maneuver the boat in a counterclockwise circle. (Turning to the right would be bad luck.) Sundays, on the other hand, are supposed to be lucky, "Sunday sail, never fail." (That being said, any type of commitment will surely be jinxed.) Never comment on how nice the weather is while aboard a fishing vessel either.
Why are 13 and Fridays unlucky? Well, like most superstitions, they may be based on religion. Friday is when Jesus was supposedly crucified and Judas was apparently the 13th apostle.
Other superstitions, like no bananas or pig products on a boat, are grounded in safety and care. You can slip on a banana peel, so why would you want it on a deck of the boat. And, pigs? Well, pigs can't swim and so they are inherently unlucky on a boat. Whistling has been known to bring on the wind and breaking a bottle of champagne on the bow of a boat before it is launched will bring good luck.
Fishermen are familiar with situations changing in an instant and circumstances that they are unable to control. Superstitions are not only good reminders, but they give fishermen an opportunity to exhibit a sense of control in an environment that is rarely predictable.
If you want to read more about superstitions that exist for fishermen you can do so on the Visit Maine website HERE. There's also a bit about superstitions in the video below featuring my husband and me.