Accumulated water

[BobRichardson]

Good morning, All.
I am the new owner of a 1966 O'Day DSI, #12796, Class 2264
The boat had been sitting out on a mountaintop in Idaho for years. It had ~3 inches of water and ice in the aft interior. After thawing it out and bailing out the water, I opened the drains under both seats. Water just gushed out !. Water also came out of the forward plug in the cuddy.
So my first questions are: how did all that water get into the seats? What damage would it have done, and how could I identify any damage?
Also this - I have read in a couple of places that some DSI's had a two layer design in the aft, and that there is a void under the sole. Is that true?
Any help is very much appreciated.

[GreenLake]

Welcome to the forum!

With a sail number of #2264 you have the original single hull design. (There's a link to a spreadsheet here, called DS1 design changes where you can look up info on boats of a similar vintage).

The three tanks (seats and front) are supposed to be air/water tight when the plugs are in. If there are leaks/openings other than for the drainage plugs, best to find and fix.

Likely, the boat had standing water and that entered the tanks via the drain holes. As long as freezing didn't create cracks, the main damage would be that the foam in these tanks is now waterlogged beyond repair.

The approved fix is to put inspection ports, or "deck plates", in the aft face of the cuddy tank and the forward faces of the seat tanks. Select the very largest set of ports you can still fit, the forward tank allows a slightly larger opening than the seats.

Before installing the ports, reach in and remove the bad foam. Replace with any good foam that will stay dry. Some people use pool noodles, some use the better kind of builders' foam cut into long strips. The key is not necessarily to get every single cubic inch filled with foam, but enough to have reserve capacity in case a tank floods when the boat capsizes. (Make sure to plug the drain holes).

After adding the foam, install the inspection ports to close up the tanks (they will narrow the opening a bit, so that's why the new foam goes in first). It's not a terribly involved fix.

Here's the hole I cut into my forward tank.