May 5
Progress continues on the sole. I've now have everything installed that can be installed. I will need to complete the ceiling (wall boards) before installing the last few sole joists in the forward Vee berth. I also completed the installation of the through hulls for the both heads. The details are in the pictures below. There are a few subtle issues with through hulls that I would like to discuss. The obvious issue is that if they are below the water line then their integrity is critical. Failure could lead to the loss of the vessel. Most inadvertent sinking occur due to failure of the below the waterline plumbing either due to a broken hose, sea cock or siphoning of water because of a lack of a vented loop above the water line. Those issues aside this fixture runs through the hull and potentially exposes the core material (wood in this case) to sea water.
The first thing I did was to make sure that there was a good surface to mount the flanged sea cock. I laid down a patch of fiberglass and added several layers of epoxy (after initial curing) to fill the weave and obtain some margin above the weave so I could sand the area smooth.
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| Prepared area for sea cock/through hull installation. |
I described the drilling of the holes earlier. I used silicon bronze carriage bolts to attached the flange to the hull. On the outside of the hull, the holes for the carriage bolts were tapered to accept the square locking part of the carriage bolt.
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| Typical carriage bolt with square lock under head. |
When I tighten the nuts, the square part digs into the tapered part of the hole and into the wood below. If I had not tapered the outside of the hole, I would risk creating a fracture in the fiberglass outer shell.
Before any bolts are installed, the holes are drenched in thin epoxy to create a water barrier and help with a chemical bond of the thickened epoxy that will accompany the installation of the bolts prior to the curing of the thin epoxy. From earlier discussion, you will remember that thickened epoxy will not bond as well to wood as thinned epoxy and once epoxy is cured, additional coats of epoxy will only make a mechanical, not chemical, bond to the subsequent layer. The trick is to use thin epoxy that will be soaked up by the wood and let it partially cure. While it is still tacky, apply the thickened epoxy.
Thickened epoxy is applied to the base of the flange, along the head of the bolts and around the head of the through hull that screws up into the flange of the sea cock. Everything is installed and the nuts (with washers and locking washers) are tightened bring the carriage bolts flush with the outside of the hull. The through hull is then screwed into the flange from the outside. Everything is wiped clean.
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| The outside of the hull showing the carriage bolts and through hull installed. Notice on the inside of the through hull fitting there are two splines. You can buy tools that fit inside and interact with those splines to tighten the fitting but any piece of metal the proper size will work. |
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| The finished sea cock imbedded in thickened epoxy. |
One thing to keep in mind is that the threads on the through hull are NPS. The NPS stands for National Pipe Straight so there is no taper and no expectation of a water tight seal without some kind of pipe dope. In this case I have used epoxy on multiple fronts to prevent water ingress into the boat and into the wooden core (in my case that would just be the plywood). There is no concern about replacing these down the road. These are solid bronze and made to last. If I need or live to replace them, the bolts can be cut off, nuts cut off, and the through hull drilled out. Usually, these are so imbedded that this is required anyway.
I also permanently installed the sole that I had previously fit. To start, I marked all of the pieces with a sharpy on masking tape and took a picture so I would not get confuse to where everything went once I dismantled everything. I got confused anyway but since I had pictures I was able to sort it all out.
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| All the piece that would be removed are labeled. |
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| The sole is installed. There are three hatches/access panels on the left that do not yet have latches. I only bought a few and I ran out. I wasn't sure how well they would work. It turns out they are perfect. I just hope I can find them again because I'll need about 10 more. |
May 12,
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| The second shower pan has been installed over the weekend and is ready to clad in fiberglass. |
