Yesterday we spent a fairly long day rebedding the through hulls. I don't think we were done until after 9 PM. We started off by going to each through hull location and dry fitting the parts to make sure everything fit as it was supposed to and to determine orientation of the parts. It is also a good time to figure out the assembly process for each through hull. You would think that you would use the same process each time, but within the confines of a boat, it doesn't work out that way. With the narrow spaces in a boat hull you need to figure out which parts you can pre-assemble and which need to be done in place. You even need to see if you can get wrenches or other tools to the locations where they are needed and that you have the room to swing them. Oh, and don't forget how you are going to apply the sealant to each of those parts as you assemble them...caulk guns aren't exactly low-profile tools either.
|What the 1.5 inch through hull looks like from the outside.|
One problem area I found and didn't really have a way around was the nut that screws on to the through hull. The nut itself is relatively thin so it doesn't take up a lot of assembly space. Unfortunately this also means there isn't much surface area to get a wrench around it. Add in the fact that boat hulls are usually curved and you are trying to tighten this nut on the concave side, and it can be a real bear to get the wrench to turn the nut.
|The 1.5 inch through hull from inside.|
Note the general lack of space around it.
Another major issue is simply dimensional space. As an example, all the 1.5 inch through hulls in the boat are in narrow spaces and require an elbow just after they penetrate the hull so the valve and hoses will run along the wall of the hull. Of course the ball valve handle sticks out far enough that you cannot thread it onto the elbow without hitting the nearby hull, even with the handle removed. So, you need to attach the valve to the elbow first. Then you run into the problem that the combination of the elbow and the valve sticking off one side of it takes more swing room to thread on than you have available. So, how do you attach all of this together and still be able to tighten that thin through hull retaining nut while not spinning all of the sealant out of the fittings and causing a leak? Heh, heh, heh...guess I'll find out if my approach worked when we put the boat back in the water.
|The air conditioner through hulls installed.|
If all of this rambling doesn't make sense, just take a good look at the pictures and the various parts and think of how you would assemble all of them together. It took us about as long to dry fit the things as it did to rebed them. Rebedding consisted of using sealant on all the threads as well as a generous bead around the mushroom head of each through hull. Assembly is a combination of NPS and NPT threads, so orientation of parts can be fun. NPS threads will just turn until the pieces bottom out, but will always leak without some sort of sealant. NPT threads can be tightened so they won't leak, but then you don't get much of a choice of which direction handles or hose barbs point. A good sealant seems critical when you can't tighten pieces enough due to the needed orientation. Since the through hulls on this boat are not the ideal proper seacocks with through bolts, I decided to go with 4200 as it is both an adhesive and a sealant but not as permanent as 5200. It appears to be what the original builder used so hopefully it will work well to both hold things in position and seal them.
|The air conditioner through hulls from inside.|
Remember the far one is at the limit of my reach.
The through hull replacement project has certainly taken a little longer than I expected, but we now have 12 new assemblies and are waiting on the sealant to cure. Of course, at under double the amount of time, I'm still doing better than that tile project on the time estimate versus reality front.