Go to Website
John, the Mariner class sailboat association maintains a web site at www.usmariner.org I don't believe the mast has a compression post, as there was a post here recently on this subject. Like any sailboat of this vintage inspect very carefully for water ingress just about anywhere on deck, specifically around shroud anchor plates, cleats, portlights... the usual. Blisters on the hull would probably have risen and been dealt with in its time, but check it out anyways. If the standing rigging is original its long past its replacement time. I believe the centreboard cable can be a weak point, make sure its functioning properly. Check out that website. Good luck.Don