Decommissioning through hulls?

[MedSailor]

I am strategically planning for my upcoming haulout...

Now that I have a composting toilet and it is here to stay, I have several through hulls that I don't need anymore. Is there a way to decommission them without major fiberglass surgery? I also may want to use them again one day for a water maker.

What about putting a threaded bronze plug into a seacock and leaving the seacock closed? Is my surveyor going to have a heart attack? Is there a better way?

Something like this in the closed position?



Plus this:



MedSailor

[Faster]

As long as the threads on both are NPT and the seacock is sound I think that would be OK. It does leave an option open... However if it's truly never to be used again I think removal and some glasswork is the way to go.

[Lake Superior Sailor]

Not needed, unused,never checked........a problem waiting to happen!...Dale

[Stumble]

Fixing a small thru hull isn't surgery, it's more of a band aid. Tape the bottom off with duct tape, and pour in thickened epoxy until the hole is full. Let cure, then remove tape.

If you ever need to reinstall it, just drill back thru the epoxy plug.

[MATHURIN]

Should definitely be removed if you don,t plan on using it again.

[MastUndSchotbruch]

Originally Posted by Stumble

Fixing a small thru hull isn't surgery, it's more of a band aid. Tape the bottom off with duct tape, and pour in thickened epoxy until the hole is full. Let cure, then remove tape.

If you ever need to reinstall it, just drill back thru the epoxy plug.

I am not a fiberglass wizard but I would be VERY skeptical about this advice. I would not want to have a plug of epoxy at the bottom of the boat, held by its rim with questionable adhesive properties.

It is not rocket science and does not take long to appropriately bevel the hole and put in the required layers of fiberglass.

[blt2ski]

Med,

In your case, ie you want to add a water maker, I would leave the thru hole there, and plug as you have shown. This way you have it available when the time comes.
For the ones you do not need, or if the current thru hole is not in the correct place, a proper patch would be appropriate. Not sure I would totally agree with stumbles simple approach. I believe as mentioned, there are BETTER ways to fill the hole in a more permanent way!

Marty

[Stumble]

Mast,

The adhesive strength of epoxy to cured fiberglass is higher than the tear strength of the original glass. The reason to bevel glass repairs is because a plug makes a hard spot in the hull that doesn't flex with the rest of the hull. For large repairs its absolutely required, but for <1" hole, just poured epoxy is fine.

[MastUndSchotbruch]

Originally Posted by Stumble

Mast,

The adhesive strength of epoxy to cured fiberglass is higher than the tear strength of the original glass. The reason to bevel glass repairs is because a plug makes a hard spot in the hull that doesn't flex with the rest of the hull. For large repairs its absolutely required, but for <1" hole, just poured epoxy is fine.

I don't buy it.

First, adhesive strength varies a lot with the quality of the substrate (roughness, presence of contaminants). I would have serious doubts about a situation where you just slap some duct tape under the hole as you proposed.

Second, epoxy is reasonably strong in compression but has low tensile strength. It is only the combination of resin and glass that is strong (just like reinforced concrete; cement putty by itself is very weak). Even if you have perfect adhesion at the rim, an impact will easily shatter not-reinforced epoxy which is quite brittle.

Third, why do you assume a <1" hole? Head seacocks are typically 1 1/2" nominal which means over 2" real, meaning the hole has an area of over 4sq in. This is consistent with the picture of the seacock shown in the original posting.

[misfits]

The proper way to do this.

Duct tape & plastic over thru hull hole inside the boat. Grind back the hull on an angle, 4+" around the thru hull. Cut fiberglass mat in circles, each one a little smaller than the next. Start w/ the largest & keep pilling on the smaller patches in sequence. Once you're at the desired thickness, slap the fairing compound on.

Do this glass work all in one shot. Once dry, sand & fair out again, apply barrier, bottom paint.

Works best w/ 2 people, you gotta move pretty quick to complete the 1st step in one hot