hm... works great for me. I haven't broken a boat accidentally in a long while! Have you tried the most recent version?
let me try to make one fast. ok nothing to prevent the destruction but Muhaha i have found a simple way to prevent the destruction by a simple teleporting. it work 100% give me 2 min to upload it My plugin prevent destruction on block only if they have a passenger in the boat. including attacker damages. Ok done: EDIT by Moderator: merged posts, please use the edit button instead of double posting.
Interesting. The changelog on 0.3.4 says "Boats won't break in water elevators". I'll have to give it a test and report back to the dev. Thanks for the info!