Uncooperative Through Hull

[dlochner]

Second Star has a leaking Groco ball valve. The leak is not in the ball valve mechanism rather it leaks around the tailpiece. It only leaks when the valve is open and it is sufficiently below the water line so that there is water in hose when the valve is closed.

I've tightened the tailpiece and replaced the teflon thread tape, neither of those have worked. Over the years the leak has gotten worse. My suspicion is the threads have deteriorated and can't be sealed well enough any more. The valve needs to come out.

The problem is that it won't unscrew from the through hull fitting. Even a big pipe wrench can't budge it. There is no access to the threads so PB Blaster won't work. Any suggestions on freeing the valve from the through hull? An oscillating tool and metal blade will work, but I'd rather take a less destructive path.

The valve is a ¾" model of this valve: https://www.groco.net/products/valves-seacocks/flanged-valves/bv-series

 

[jssailem]

Sounds like maybe a cross thread issue or a gall cold fusing of the threads. Perhaps heat and cold will break the threads loose. Torch and dry ice.

In the yard I’ll bet time is money and they would cut it off and install all new. How old is the thru Hull? Does it owe you any longer life, or is it depriving you of sail time?

 

[Benny17441]

Respect the old maxim, when working on frozen thru-hull valves first remove the boat from the water. The last thing anybody would want is to break the seal of the thru-hull and not have the tools and a diver and a backup plan in place.

 

[dlochner]

Respect the old maxim, when working on frozen thru-hull valves first remove the boat from the water. The last thing anybody would want is to break the seal of the thru-hull and not have the tools and a diver and a backup plan in place.

But it only leaks when it is in the water.

 

[jssailem]

But it only leaks when it is in the water.

Yes this is true. This is where you need to apply your higher thinking skills then the boat. Knowing that it leaks allows you to remove it from the water to alter the environment and use the opposing thumbs evolution provided us to solve the leak.

We are smarter than the average boat, in most cases. But I will admit sometimes my boat does not play nice and tries to fool me.

 

[DArcy]

Could you spray PB through the drain plug hole? I'm not familiar with these valves but if you squirt enough in there some may end up on the through hull thread. Or, do you have access with the fitting off the top of the valve and with the valve open to spray inside? Other than that, careful application of heat with a heat gun might help. Just monitor how much heat is getting to the surrounding fiberglass.

 

[Bob J.]

When I removed a couple of thru hulls & glassed over them on my 28 I left the flanged seacock in place & spun the thru hull off from outside the boat.
It was alot easier than trying to manipulate a wrench inside the boat

 

[Davidasailor26]

But it only leaks when it is in the water.

I think Benny's point (or at least what I would take from it) is that when you're twisting and putting force on the stuck part you may accidentally unseat or break a seal on something below the valve. Then you've got two problems, one of which is much more exciting when in the water.

Also, are you absolutely sure that the leak is from the tailpiece, and not a cut in the end of the hose that's just wicking down to there? I've had hoses chafed by hose clamps that kind of presented that way.

 

[dlochner]

Thanks for all the suggestions. First, the only way I would attempt to remove this while in the water would be if the keel was firmly planted in the mud. I have seen how much water can come in through a hole in the hull. Also, I live in Central NY, the ice has just gone out and it snowed a 2 weeks ago. Too cold to put the boat in the water.

I am quite certain the water is coming up through the threaded portion of the tail piece and not coming down the hose. The hose is new and is removed and inspected every fall, it is the intake for the head. I can see the water coming up from the the hole. It has also gotten worse each year which would be consistent with corrosion or threads failing.

Heating isn't really an option, the seacock is located in a small enclosed space. Easy access to open and close it, but not so much for a large wrench.

I was hoping for a non-destructive way of removing the valve so as to not destroy the mushroom through hull fitting, but that is only a $20 fitting and if I am correct the valve is toast so destroying it isn't an issue.

Finally, I took some of my own advice and RTFMed. If Sabre installed the through hull per Groco's instructions there is a sealant (5200?? ) on both the outside of the hull and the inside so that the valve is glued in place. See the drawing. The valve flange is lag bolted to backing plate.

 

[jssailem]

I will say a prayer for the fitting as you prepare to remove the offending parts.
Good luck Dave, and may the Force be with you.

 

[DArcy]

Can you heat it from the outside? Take the hose off, open the valve and stick a heat gun (or hair drier if you are worried about melting the boat) in the thru-hull. Hold a finger on the hull beside the thru hull until it starts to warm up then have at it with a wrench.

 

[dlochner]

Can you heat it from the outside? Take the hose off, open the valve and stick a heat gun (or hair drier if you are worried about melting the boat) in the thru-hull. Hold a finger on the hull beside the thru hull until it starts to warm up then have at it with a wrench.

It is only a ¾" fitting and I don't think 5200 or the other caulks will soften enough to work.

For a variety of reasons I'm late this year getting to the spring launch list. In the end it is a time and money issue, how much time am I willing to spend to get this sucker off.

I will say a prayer for the fitting as you prepare to remove the offending parts.
Good luck Dave, and may the Force be with you.

Bronze valves and through hulls are no match for a carbide blade on an oscillating tool.

 

[jssailem]

Bronze valves and through hulls are no match for a carbide blade on an oscillating tool.

I like your style.

 

[NYSail]

If you are sure its the tail piece and you can remove it, have you inspected the threads? I don't like to put too much twisting pressure on fittings as I don't want it to budge and break the seal. And would be very apprehensive of adding heat as it may soften sealant and damage seal. But if just keeps getting worse take the opportunity and just cut the bastard and replace the whole thing.... mushroom and all!

Greg

 

[dlochner]

If you are sure its the tail piece and you can remove it, have you inspected the threads? I don't like to put too much twisting pressure on fittings as I don't want it to budge and break the seal. And would be very apprehensive of adding heat as it may soften sealant and damage seal. But if just keeps getting worse take the opportunity and just cut the bastard and replace the whole thing.... mushroom and all!

Greg

I have removed the tailpiece and it looks OK, I think the threads in the valve are the issue. Once I found the installation instructions and saw the caulk on both sides of the hull, I realized that a non-destructive approach was going to be more frustrating and time consuming than I have patience and time for.

 

[Ward H]

Maybe instead of using teflon tape try using something like Sikiflex 291? Might seal better and delay the hassle of replacing the ball valve this year?
Never really understood why teflon tape was using for the tailpipes instead of 291.

 

[dlochner]

Maybe instead of using teflon tape try using something like Sikiflex 291? Might seal better and delay the hassle of replacing the ball valve this year?
Never really understood why teflon tape was using for the tailpipes instead of 291.

Ward, we've been living with the leak for 5 years now and it has worked its way to the top of the to-do list. Also, next spring we'll be pushing for an early launch as we plan to head out the St. Lawrence in mid June. It is just time to take care of this before we leave.

The threads are NPT so teflon tape should work just fine. Same threads are keeping the natural gas in my house safely in the pipes. Sikaflex would seal it, but make it difficult to change the tailpiece if that ever needed doing.

 

[Ward H]

Makes sense to me. Time to break out the multi tool.

 

[BigEasy]

Dave,
I changed a couple thru hull fittings, valves, and tails on my last haul out in November. I used a grinder on the outside of the hull. Bronze is fairly soft and I was able to cut off the mushroom portion of the thru hull fitting in about 3 minutes. The concave surface of the mushroom that faces the hull is filled with sealant; therefore, just grind the mushroom where it intersects with the actual thru hull portion. The mushroom falls off and you can remove the remaining thru hull portion, valve, and tail from inside.
Simple and quick, no scraped knuckles, and no swearing; of course, you're out a few bucks to purchase a new fitting. Seems that there is never enough room inside the boat to remove them nondestructively.

 

[dlochner]

Dave,
I changed a couple thru hull fittings, valves, and tails on my last haul out in November. I used a grinder on the outside of the hull. Bronze is fairly soft and I was able to cut off the mushroom portion of the thru hull fitting in about 3 minutes. The concave surface of the mushroom that faces the hull is filled with sealant; therefore, just grind the mushroom where it intersects with the actual thru hull portion. The mushroom falls off and you can remove the remaining thru hull portion, valve, and tail from inside.
Simple and quick, no scraped knuckles, and no swearing; of course, you're out a few bucks to purchase a new fitting. Seems that there is never enough room inside the boat to remove them nondestructively.

Thanks, hadn't thought of that approach. I might give that a try if it ever stops raining.