I've found that avocado boats kept sinking when poked by cats and / or humans.
This one has been modified to be printed with low infill to allow it to float.
Update! This sunk :D
It appears to be due to water leeching in between the layers.
Either spraypaint or vapour smooth the whole thing to waterproof it, or print with at least 5 shells, and bump the infill to 20% to make it fine enough that only a few cells fill if it does leak.
Print with 5 shells top / bottom / sides or it might sink!