So I was running around carrying a random boat I found (it appeared to be fairly damaged when I picked it up) and filled it with some logs that I also happened upon.
After 30 min or so of walking, the boat disappeared (presumably from decay) in my hands and the logs that had been inside disappeared entirely.
I don't know if boats are supposed to continue decaying while on land/being carried, but it seems rather bad that the items inside get destroyed when the boats do.