Paint the keel inside

I bought a small dinghy and it has a wooden keel. I made some comprehensive repairs and fittings. Now i need the paint the interior.
She has a pretty thick(around 20cm wide) wooden keel. Which type of paint i should use? Should i worry about breathability? For example, if it takes some moisture from outside, it should be able to breath inside and give the moisture away from inside.

 

Wood does not breath. Dinghies are mostly out of the water so an oil based (alkyd) paint will do fine. There is always some moisture in wood. Even epoxy will absorb a percentage of moisture. Wooden dinghies have been painted for many decades with paint without problems.

 

Most of what kills wooden boats happens on land, poor storage and poor maintenance once the love affair finishes. Love her and look after her and she will respond in kind. Basic oil based paints as Gonzo mentioned are cheap to buy, easy to apply, and easy to touch up.