Not sure how it works in Kansas, but here in Virginia I got the contact info for the former owner of my Com-Pac 16/III
"Foundling" from the state agency that does boat registrations, based on her expired registration number--just in case your old boat club isn't forthcoming with an address for that Mac 26M owner or unwilling to forward a message.
If you can also get your hands on whatever engine was once on that 26M, and it was manufactured more or less at the same time (and not just some old banger they thought might work), then you might do well to try and get that as well if the price is "speculative" (read: "parts donor cheap" or free). After all, a year is more than enough time for the Devil Ethanol left untreated and unchecked to do its evil "snots and clots" routine, knocking out even a new engine in a matter of months. If it's a nice otherwise pretty bulletproof Honda BF50 (probably the commonest power plants found on Macs) it might not be too difficult or expensive to get her back in the pink. In fact, a pint or so cocktail of equal parts SeaFoam and Marvel Mystery Oil bulb-fed right through the fuel line into the carbs and allowed to marinate for a week or more might help ease out enough fossilized snots to get her kicking again without needing to tear the carbs down for a proper cleaning. You might also do well to pull the sparkplugs and squirt a health shot of Marvel into those cyclinders.
Anyhow, something to consider if you're gong that route, since a newish Honda 50 or comparable will run you easily 5 "boat bucks" on a good day...in winter...with a Nor'easter bearing down...and coyotes roaming the aisles of the abandoned Walmart as you and your rag-tag band of survivors of the Corporate AI Wars arrive, fierce and resplendent in your Beadazzled leather battle hotpants, on a Pop-Tarts and Twinkies foraging run. Just sayin'...