For any boat of this age, there are vast differences between boats that have been well kept and those that have been neglected. The most critical differences are areas where
water intrudes from below or above. If those have been well kept, everything else is relatively easily repaired.
Have the boat dived with a video
camera and ask the diver to get close-up video of all thru-hulls and the leading edges of the
keel and
rudder. Also get video of the condition of the zincs and prop. Bottom
cleaning divers are known to every marina office, so just ask them for a recommendation.
Inspect the
keel bolts and the
fiberglass around the
keel, and the leading edge and bottom of the keel itself for signs of hard groundings. Groundings can cause invisible damage to the bottom of the
hull that can make a bolted keel unsafe. If there is signs of grounding on the keel, you'll want to have the boat hauled and closely inspected.
Check the
shaft seal and be sure it's not leaking. Listen for a running
bilge pump while you're inspecting the boat. Look for a wet
bilge, inspect the thru-hull fittings for
corrosion. Inspect the
rudder post and fittings. Thru-hulls are often hard to find inside a boat, so use the diver's video as a guide to where they ought to be.
Inspect the chainplates looking for signs of
water intrusion below or around them. Also inspect the
mast step at the top of the
compression post for signs of water intrusion.
Look for white
corrosion on the
mast fittings, especially the gooseneck attachment for the boom.
Test the standing
rigging for proper tension (it should stand up stiffly to your weight pulling on it on both sides), and inspect the swages at the chainplates. If they look good, with only minor surface corrosion and no fraying, they're likely fine. Otherwise you should
budget to replace the standing
rigging. If the standing rigging seems lose, the boat may have undergone shock-loading which would require additional
inspection of the mast foot and the chainplates.
Expect to replace the
batteries, and test all the
electrical panel switches.
I would not expect significant problems from the
Perkins diesel or the
clutch. If it runs easily at test and doesn't smoke too badly, it likely needs nothing more than routine
service.
I would personally
budget about $15,000 to replace
sails, standing and running rigging, and electrics/electronics, pocketing the savings for whatever is good enough to keep.