Anyone know what this is in my O’Day 26? The bolts are coming straight up through the hull under the starboard forward settee. The yellow wire is heavy gauge and is disconnected at the other end, but looks like it was connected to the negative bus. I bought the boat two years ago, and just discovered this, and I’m completely stumped!
The wire is some kind of bonding wire to connect whatever is on the other side of the bolts to ground. Hard to say what it is without seeing the other side though.
I certainly don't "know" but I'd bet money on it being the remnants of a lightning defense.
There's likely a plate, or remnants of a deteriorated plate on the outside. If that's the case, and you want to resurrect it, I'd get way larger wire on that and run it to multiple or every piece of chain plate and keel base that you can.
Probably something like this:
Guest Dynaplate Standard Grounding Plate | Defender Marine
Guest Dynaplate Standard Grounding Plate | Defender Marine