Thru Hull Upgrades
This fixes one of those things that has been nagging me since I got the boat. The drains for the low point of the deck run down to small thru hulls. These are above the waterline but close enough to it that I put valves on during the first refit. This left a hose running through the cockpit locker mixed up with all the stuff stored in there. In addition to looking untidy, it increaed the chances of putting enough strain on the through hull to break it off. I ran solid pipe up and bracketed it securely to the structure and the hose now runs out of sight overhead.
The Groco valve is threaded onto the through hull which isn't considered best practice since there is a mismatch between the tapered and straight pipe threads. It's been done for years however and, after threading some trial fitting together, banging on them, and inspecting them after taking them apart, I decided it isn't as bad as it's made out to be. No question though that it isn't as strong which is why I wanted to get some additional support and move the hose. Groco makes some nice flanged adapters but neither the adapters nor seacocks in this 1/2" size. I decided this was good enough for an above the waterline fitting. The handle is kept in the small locker just above so it won't snag on gear in the main locker and is quickly available.
I learned something new on this project. All those pipe nipples in the rack with the bronze fittings at the marine store are red brass. This metal isn't suitable for long term salt water immersion so I did a web search for bronze nipples. They aren't available which is why so much hose is used below the waterline on boats. The brass and bronze also shouldn't be mixed if salt water is going to stand in the pipe. Since this is an above waterline fitting that a lot of fresh rain and wash water goes through, I decided it was acceptable. I'm sure a surveyor will disagree with me if I sell the boat but I don't plan to ever do that. Don't do something like this below the waterline. I'm going to tape one of those tapered wood damage control plugs right to the pipe.
Upgrading the holding tank discharge with one of the Groco flanged adapters. The line goes to the
original direct discharge and, if that 1 1/2" fitting should break, there would be a lot less time to deal
with it than if one of the 1/2" through hull / ball valve combinations should break off. If I'd known how
firmly the NPT ball valve was on the NPS through hull and how good the threads looked once it was apart, I might
not have been in such a hurry to do this but it's nice to have everything below the waterline up to ABYC and best
standards. Once it was apart there was no reason not to put it back together right.
The through hull itself is solidly in the boat and the backing block was sound. I didn't want to try cutting it to the shorter length required for the adapter in this small space under the head sink. (Fixing funky ground wiring was also part of this project.)
I discovered that three layers of 1/2 inch plywood were just the right thickness to go under the adaptor so I cleaned up the surface of the backing block and screwed the plywood on layer by layer with epoxy between and bedding compound around the through hull. After it was together, I gave the whole thing a good coat of epoxy.
After the epoxy kicked, I screwed the adapter on and lagged it to the block. With the through hull nut holding the original block on and the screwed and glued block, it will be very strong.
Next, the head intake thru hull. This part of the boat is done except for screwing the sink cabinet door back on.
This thru hull came out easily so I was able to cut it to length without adding onto the backing block. Once I got the head intake valve off, I could see the value of wide flange of an adapter or seacock. This is a frequently used valve and the slight working of the small area thru hull nut on the wood backing block. It would eventually have let water under the flange to the wood and possibly rotted the backing block. It was well worth doing this. The wide flange and lab screws will resist the force of even a sticky ball valve.
The blue valve goes up to this sink tailpiece. It lets me use fresh water draining from the sink to flush the head. Doing this periodically flushes the salt and critters out of the water closet and sweetens it up. It also gives me an alternate way to drain the sink if the long hose back to the bilge should clog.