The standard equipment on the boat are gate valves. These have the benefit of being cheaper, and that's about all. There are many online sources that discuss in great detail the specific reasons why gate valves are a poor choice for marine service. It basically boils down to valve that is used because its cheaper for manufacturers to install them. It should also be noted that this practice is still ongoing with current production boats.
After 38 years, mine are corroded and frozen in whatever position they were last left in. Although this was the main reason that spurred me into action, as we will see, there were other problems that were lurking in the rest of the plumbing that only reinforced this decision.
The decision to go with new seacocks sets up another decision on which brand/material to go with. The options for me were Marlon(plastic), or Bronze. After doing a fair amount of research, I decided to go with bronze, and to use the Groco line.
This decision was not due to distrust in the Marlon material. I have some experience using valves of this type, and the strength and durability is quite adequate for the purpose. The factor that tipped the scales was the flexibility in mounting/installation options that the Groco IBVF line offers.
The IBVF line is a modular set that can in include a mounting flange, through-hull and valve body. There are options for threaded or hose connections, straight or angled, of various sizes. Due to some space constraints, I needed the options that this line offers. More specifics on that as I go through the installation process that I took.
Here is a link to the website that I used as a template for a this installation. It is an excellent resource, very well illustrated, and is very well thought out in its presentation. The gentleman who developed this site is a wealth of quality information. I highly recommend browsing his site for other posts that are just as informative.
Out with the old...
The first step was to remove all the old plumbing. This was relatively easy as I was not at all concerned with saving any of it, so hacksaws and box cutters were the order of the day. The original hoses were all dried out and rotted. As I started removing valves, some of the hoses were basically falling apart in my hands, or splitting and cracking as I flexed them! Definitely time to replace.
Also found all backing plates to be made of plywood, and rotten. Through-hulls were installed using a nut, due to lack of a more traditional flanged seacock, and were all very loose. Any bedding material had long ago dried up and become worthless. The fittings were just spinning around in the hull.
All in all, what I found after digging into it was much worse that I had originally suspected.
Here is all the old hardware. Notice the broken valve handles, rotten plywood "backers", and assorted home center hardware:
Prepping the through-hull openings...
In researching the best practices for through-hull installation, it is generally understood that the backer plates should be a glassed in part of the hull itself. There are options for what materials to use, but I chose to go with fiberglass. Its a little more work up front, but not much more. The alternative is to use plywood which would have to be completely sealed with epoxy anyway. There are other materials that other people are using, but with questionable long term results. Fiberglass seemed the more bulletproof material.
I created a "layup", to use the parlance, of alternating layers of fiberglass cloth and roving, using West System epoxy resin. This was about 16" X 24" in size. I kept adding layers until I reached an overall thickness of about 1/2". Then, once the layup had cured, I used a large hole saw and a drill press to cut out a fiberglass discs from the layup.
I then took the time to completely flatten 1 side of the disc on my combination sander. This side will be the "up" side that the through-hull flange is mounted to. The other side, I sanded just enough to roughen it up some to create a good surface for bedding to the hull.
Meanwhile, back on the boat, I prepped the hull surface surrounding each hole in the hull where the backer plates were to be bedded. I used an angle grinder with a rough sanding disc attached to clean up the areas. The last step was to wipe down all surfaces involved with some Xylene to insure that they were clean and dry.
Lets pause here for a moment to explore the concept of fiberglass and human skin. Now, if you are like me, I don't plan to make a career out of fiberglass work. I took moderate precautions when doing this project(dust mask & safety glasses). If I had to do it over again, I would have taken into consideration the time of year and ambient temp(dog days of summer, 95 F.), as well as the level of contortion required to access the areas that needed sanding/grinding prep, and probably put this job off till late fall or winter. You have never itched until you have coated yourself with a sweaty, slimy layer of fiberglass dust and dirt. It stays with you for a few days as well, as a reminder.
Now that I had my backer plates fabricated, and the hull prepped to receive them, it was time to have the rubber hit the road. I mixed up a batch of thickened epoxy to a peanut butter consistency. For each hole, I applied a liberal amount of epoxy to the hull and to the backer plate. Then, with an assistant outside, I applied the backer plate to the hull, and had my assistant help to center the plate over the existing hole. I carefully sculpted in a fillet around the perimeter of each disc for strength, and allowed the epoxy to cure.
You may notice that I have differently sized the backer plates due to the differently sized through-hull flanges. This may be a bit more anal than necessary, but that's me. Although, in my defence, there were some space constraints to deal with as well.
Now, it was time to open up the holes to the correct size for the through-hull fittings. This required more drilling with hole saws. Keeping the hole centered was easy at this point as I already ensured in a previous step that the discs were centered. You can see above the original hole that is cut when I fabricated the disc and cut it from the layup. This was then used to pilot the hole saw for the final cut.
What was difficult was keeping the hand drill positioned perpendicularly while cutting through about 1" of epoxy and fiberglass. This wasn't a problem on most locations as I drilled it from outside in. A couple of them had to be drilled from inside out however, and they are never in a good location for easy access.
Note: Everything done up to this point was completed last summer. The following was completed this spring.
Next, it was time to measure and cut the through-hull fittings to the correct length for the flanged base. As shipped, they are all easily 1-2 inches too long to achieve a good fit. This was accomplished by threading them into their mating seacocks, measuring the resulting gap and adding 1/4" for good measure. A sharp hacksaw makes quick work of bronze.
Drilling 24 holes in a perfectly sound hull...
It may seem counter intuitive, but in order to install a seacock, one must drill even more holes though the hull for the mounting bolts. Since I have 8 installations, that means 24 holes, preferable drilled perfectly perpendicular to the hull. I can tell you that is easier said than done given some of the tight areas that these are in. In the end, I did fairly well, but it took a combination of acrobatics, right angle drills, and perseverance.
One of the keys here before you begin drilling is to thoroughly think through the shutoff valve arm position in relation to the other seacocks, as well as any other interference from bulkheads or hose routing. Once you start drilling holes, you are pretty well committed to 1 of 3 possibilities. There is some wiggle room afterwards by over/under tightening the valve body onto the base flange a bit more, but thinking ahead will pay off by not having to cut corners.
Here is a shot of a dry fit installation:
A couple of points to note here are the counter-sunk bolt holes, deep enough to recess the bolt heads for later fairing and painting. Also, you can see where I filled in the old flush fit through-hull to accept the new mushroom head. I did this for 2 of my through-hulls that were originally 1/2". Since Groco does not make a 1/2" through-hull in this product line, I had to enlarge those to 3/4", and do away with the flush fit install. One last point is to note the bronze bolts were used here as the seacocks are also bronze.
Here is a shot showing a cluster of 3 showing a couple of reused flush fit through-hulls. The empty hole will house a transducer:
At this point, I was ready to seal these in for good. At this point, this task was about the easiest thing about this project. One person in the boat was in charge of spreading sealant on the flange base, and mounting the flange to the backer plate(always keeping the correct valve arm orientation). The other person is outside sealing the bolts into their holes. Tighten down and check the fit of the through-hull. Then apply lots of sealant to the through-hull fitting, and thread it into the flange and tighten. Clean up after yourself, and you're done!
Some shots of the finished installations:
The next step will be to connect up all the new hoses to the seacocks.
