Here's another one I forgot about.

This is for turning the boat over to do bottom work or painting.
Just hope you got two trees a little longer than the boat apart and choke a chain with come-along up in the tree and connect to the bow eye and this thing on the other end up the other tree with chain and come-along.
One person can lift the boat and turn it over this way.
If your careful, a tree and engine hoist will do also.