Hi Bill and other M-ers, Okay, I'll take a stab at this one - although I think some of it might already be mentioned in Jerry Montgomery's "History of the M-17," which is ... I can't remember where to find it - must be on MSOG somewhere. I think most of the major changes took place in 1981, when they made a new mold because the old one was getting a bit worn from use. My old hull #331 was apparently the first "new" boat. I say this because I found an older-style M-17 which was also a 1981 and also had hull #331. At any rate, it was 1981 sometime. I'll list what I remember as the changes: 1) Improved hull-to-deck joint. Not sure exactly how the old one worked, but the new one protrudes more on the outside and takes both the hull and deck and folds them into an upside-down U-shape together. I believe that all of the old boats had the perforated aluminum toe-rail, whereas most of the new ones had the teak toe-rail, but a few had the perforated aluminum (which was apparently more expensive and harder to install, and probably more functional; but apparently "the public" preferred teak). The improved hull-to-deck joint also ran all the way across the transom (thus the motor cut-out was eliminated), giving it much more strength (I have seen a number of the older boats that had small cracks running vertically at the place where the transom turns into the topsides.) 2) In the cockpit, the cooler was eliminated from the "benches," and the benches were made completely flat (I believe, but am not sure, that the older model had some diagonal grooves at the forward corner of the benches for drainage? That's what I was trying to say when I said the new ones were flatter.) 3) In addition to the motor cut-out being eliminated, a "wet locker" was created across the back of the cockpit. Essentially a continuation of the cockpit "benches" across the stern, but isolated from all other lockers and inside spaces. It had a lifting lid, just like the other bench lockers. 4) Cockpit drainage: IIRC, the older boats had copper tubing glassed into the hull for cockpit drains (or just one drain?). My early-new-style 1981 had what I believe were fiberglass tubes glassed into the bilge for cockpit drainage, but the tubes were below the waterline. I think that newer-new-style boats went to above-the-waterline transom drainage, but I don't know exactly when. I think the newest boats utilize a one-way valve to allow water to go out but not come in ... ? 5) Forehatch: The pre-1981 boats had a forehatch that was flush with the deck, whereas the 1981-and-later boats have a hatch that sits "on top" of the deck. 6) Ports: The pre-1981 boats had ports with aluminum trim rings around them, whereas on the new mold there were recesses molded into the coach-roof sides, and the ports just bolted right into the recesses, with no trim rings. 7) Backstay attachment: I don't remember how the backstay was attached on the older boats (perhaps stainless tangs bolted to the transom?), but on the newer boats - with the rolled hull-to-deck joint - (hazy memory alert!) there is a short piece of what looks like re-bar (but which must be stainless of some kind) tucked into the groove created under the hull-to-deck joint's lip, and the backstay fittings are anchored in that way. 8) Below-decks layout: I'm fairly sure that all of the pre-1981 boats had the one settee (quarter berth) + galley layout, whereas starting in 1981, you had a choice between that and two settees (which both doubled as quarter berths). Now I'm really straining my memory, but I think with the two settee layout, the cockpit lockers were small, ie: you lost the great cockpit-locker stowage you had with the galley model (unless you cut them out later on) (more on this below in "later mods"). 9) Things I'm not so sure about: ... At some point, the centerboard-raising winch might have been moved outside? Or maybe it was eliminated with the fiberglass board? (See below). I also think that the main-sheet traveler might have been moved around a bit in the cockpit. Were earlier ones closer to the companionway? I believe mine on hull #331 was about 9" to 12" abaft the companionway. I always wondered if the "turn" from the coachroof to the coachroof-sides might have been a squarer profile on the pre-1981 boats -- or perhaps it was something I just *thought* I noticed when looking at a shot of the bulkhead at the rear of the cabin (as in a photo looking from the tiller towards the bow). 10) Later mods: Starting around 1986, you could get a "short settee berth" instead of either the galley or the second full quarter berth. Then you had the advantage of two people being able to sit facing each other below AND the huge cockpit locker of the galley model. Also in 1987 (IIRC), the centerboard went from iron to fiberglass with lead (early on maybe steel?) ballast encapsulated in it. The new board is wider than the old iron one, so the keel stub was modified at the same time to accommodate the new board. Also, whereas the old, iron board had a "stop tang" to keep in from dropping too far, the new fiberglass board utilizes a knot in the rope, like the M-15 does. That's all I can think of right now. There's probably more - and I've certainly erred in some of my "facts," so feel free to correct me! --- Rachel Boat shopping for something a little bigger than the M-17 (to live aboard), but darn! you have to go SOOO big to get much more than the M-17 offers - it's especially hard to beat that fine cockpit layout.