Originally posted by Complaintdesk:

Ship damage (when not the result of hitting rocks) in my experience, is gradual over time regardless of the weather or wave action. It is almost like it is timed to happen every 10 or 15 minutes. My longship takes 10 damage regularly whether I am in stormy or calm seas. It does damage when travelling at a high speed when there are large waves & rough seas waves, when the ship goes somewhat vertical getting air between it and the water, but apparently that type of damage can not trigger more than once every couple of seconds.

Gradual, over time damage isn't supposed to happen. You may be hitting deeply submerged rocks that you can't see but are just tall enough to scrape the bottom of your ship. This has happened to me a few times, especially if I'm near very tiny bits of land on the edges of the ocean biome, but otherwise there's no type of gradual decay for the boats.