I bought my 1976 Helms 25 about a year ago. I sail in Delaware and this was a Peroia, Ill fresh water boat. It was complete with original trailer and a good condition 15 hp outboard. One main and 2 head sails that are old but clean and not torn but stretched out from age. Had a survey done on the deck before buying. PO put new bearings and lights on the trailer. Bought it for $5000. Going price for good condition 1976 Helms 25.
The reason I picked a Helms 25 was for the ballasted fixed keel with a draft of 20". It also has a 300# centerboard with a 6' draft all the way down. The air draft is 33.5' which allows me to get under 3 35' bridges in my waterways. I really like this boat. It points well, handles rough weather ok, has a large cockpit for day sailing. Its not the fastest boat on the bay with my old sails. Mine is a popup which added a lot of head room when at anchor. For my use in shallow bays, I think it is a nice choice.
I'm curious why Tartan34C thinks it lightly built. I'm not an expert and would want to keep an eye out in the areas you think are marginal. Can you point them out for us? I know the bulsa cored deck has to be kept dry, but that's true of all bulsa cored decks of that age.