Hi Andrew,
We've had our bilge keel M29 for 27 years and are very happy with it. It suits us well, having bilge keels for sailing around small creeks and harbours on the south coast and occasional trips across the channel. As you will know, it has loads of accommodation space for its length and sails OK, often keeping up with some more sporty designs. I'm not aware of there being a Mark I and II, but obviously built over a number of years the design has evolved.
These are old boats now, although we're originally well built, so could have a number of potential problems. I would strongly recommend a survey by someone who has experience of Moody's.
At lot depends on how well any Moody has been maintained. As with all Moodys if the keel bolts have been left submerged in bilge water they will be very rusty. Fin keels worse than bilge, if there is some bilge water lying in the bottom. Our boat has a very dry bilge and I make sure it stays that way. Keeping on top of any leaks above or below the water. There is a good article on keel bolts applicable to all Moodys.
Something to look for on all Moodys is the chain plates. Look for any signs of deflection of the side decks with a straight edge. Look for signs of water leaks around the chain plate where it passes through the deck. Look inside at where they bolt to the main bulkhead (inside the cupboards port and starboard). Unfortunately you can only see one side, but if there are signs of leakage here or soft plywood, you need to look further. Repairing rot in the bulkheads would be a major job. You can search this website for articles on chain plates. The baby stay in front of the mast is a particular weakness on many Moodys.
The Rudder, is transom hung on pintles, so it's good that you can see and feel if there is any wear. They may rattle a little when moving under power at top speed, but that's not a concern, as long as you cannot feel any sideways movement (out of the water).
Look for signs of leaks above the water, around windows, or hatches. Most M29s should have had windows and hatches replaced or reglazed by now. Also check around the accessible areas of the deck to hull joint, especially in way of stanchion bases or electrical cable deck penetrations.
Engines may have been replaced. If still the Bukh 20, then it may have overheating problems due to blocked water channels inside the block. (Flow of water out of the exhaust may seem ok, even if blocked). Run the engine under load for at least half an hour and check for any steam/white smoke.
Check circulating water pump, by looking under the pump, there should be a tell tale hole, which should not be blocked or dripping, otherwise a sure sign the seals have gone. Exhaust elbow, if cast iron, may be blocked or corroded from the inside (look for cracks or signs of rust on the outside). Engine mountings may be at end of life.
Check stern gland, rotate shaft by hand and feel if even all the way around as you turn, for any misalignment or binding. Listen for any wining sound or heat on the gland.
Paul
