I'm experimenting with water based enamels and have used it on the boat hook as well as the cabintop on my boat. The stuff seems tougher than oil based one part enamels. Paint is easy on a boat hook, a quick sand and a couple coats every 3-4 years keeps the boat hook handle from deteriorating(it will, unprotected). Besides, a varnished boat hook would be redundant on my boat.
This boats builders located a very handy place for a boat hook. It's right on your way to the bow.