The photo above shows the backside of a modern sailboat winch mount. What you can see are five of the mounting bolts that pushed their way through the fiberglass. There are not nuts on the bolts and oddly, the bolt pattern is a bit asymmetric, which indicates to me that the installer didn’t install bolts in all the available mounting holes for the winch. But that’s not all I see. I see what could end up being a real service pain 10 years down the waterway. You see the builder in this case has installed an aluminum back plate into the deck laminate that is pre-drilled and tapped to accommodate the mounting bolts. That’s why you don’t see any nuts in the photo, the bolts are threaded through the aluminum plate. What you really can’t see in the photo is the fact that upon really close inspection, I found no evidence of any sort of sealer having been applied to the bolts before they were screwed into place. What this says to me is that eventually water will find its way into the mix here and the stainless bolt will corrode, meaning it will be really tough to remove when the time comes. The bolt may even break when someone tries to remove it. The net result? A long rotten Saturday trying to drill out whatever is left over. Now, this may not be such a terrible thing in the case you see here because access isn’t really a problem in this case. But bear with me a moment here as I share a real world example from here at the boatyard that turned into days of really expensive grief for one lucky new boat owner.
It seems that more than a few of the builders today are employing this method of imbedding aluminum strips into their hulls along the entire perimeter of the hull to facilitate screwing down the hull to deck joint. On the surface this seems like a really great idea compared to having to hand tighten a series of nut and bolts that can’t be easily accessed behind cabinetry and such. But in the case that I just witnessed the boat builder had used this imbedded backing plate as the hold-down point for a bow cleat that for some reason had been broken. One of the two bolts holding the cleat in place had broken off just below the deck surface. Replacing the cleat turned into an absolute nightmare because there was no way to access the imbedded aluminum plate from the backside in the location of the cleat and the stainless bolt that had broken off was not exactly easy drilling. Further, there was now the issue of trying to make sure the threads in the relatively soft aluminum were still in tact and useable with the same size bolt.
Several days later, the new cleat was installed. At full service boat yard rates. Not the yard’s fault in my view but certainly food for thought on this aluminum plate in the deck or hull laminate concept I’m beginning to see more and more on new boats.