The bug

First of all, I'm not sure the exact circumstances when this happens. This definitely works in small bodies of water, such as ponds, but I tried it in the ocean and it did not work. So basically, when the player right-clicks on the boat, around a half of a second after getting in, all of the boat will suddenly become a slightly darker color, and then about a quarter second later it will become it's normal color again. This happens for all boat variants.

The images attached are both of the same oak boat in the same position. One of them is when the boat flashed dark and the other is its normal color.