I am going to replace a gate valve that leads to a through hull. Any advice would be welcome. Am I likely to damage the through hull? Does the gate valve need some sort of liquid or chemical loosening before I try to get it off? Thanks.
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John Tesoriero
Go slowly
I replaced two 16+ year old gate valves a few years back. They were bronze valves on bronze thru hulls and came away relatively easily. I dosed them with lots of WD-40 (inside and out) over several days. You may need a helper outside the hull with a tool inserted to keep the thru hull from turning. I had one thru hull turn and one stayed tight. I would advise removing and rebedding the thru hull just to be on the safe side. You don't want a leak where you can't fix it without doing the whole thing over again.
I replaced two 16+ year old gate valves a few years back. They were bronze valves on bronze thru hulls and came away relatively easily. I dosed them with lots of WD-40 (inside and out) over several days. You may need a helper outside the hull with a tool inserted to keep the thru hull from turning. I had one thru hull turn and one stayed tight. I would advise removing and rebedding the thru hull just to be on the safe side. You don't want a leak where you can't fix it without doing the whole thing over again.
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Jim
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John K Kudera
If you are out of the water,
Do NOT try to remove the gate valve. Your best bet is take the valve apart, and use a right angle grinder to cut it in half,top to bottom, or use a reciprical saw with a metal cutting blade, to cut the same way. Cutting may cause you to change the thru hull, but this probably should be done too! My gate valves were corroded to the thru hulls, there is no room on most boats to turn a wrench anyway, so cutting both the valve and the thru hull nut was my only answer, made a big job easy.
Do NOT try to remove the gate valve. Your best bet is take the valve apart, and use a right angle grinder to cut it in half,top to bottom, or use a reciprical saw with a metal cutting blade, to cut the same way. Cutting may cause you to change the thru hull, but this probably should be done too! My gate valves were corroded to the thru hulls, there is no room on most boats to turn a wrench anyway, so cutting both the valve and the thru hull nut was my only answer, made a big job easy.
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Daryl
If you ...
turn the thru hull fitting and need to rebed it replace the wood backing plate if you have an older vessel
turn the thru hull fitting and need to rebed it replace the wood backing plate if you have an older vessel
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Chris Burti
Been there, done that...
I did it in the water on my 30-year old Cal's OEM 1-1/4" head discharge a couple of years ago. I had no problems but proceeded with much caution and a certain amount of trepidation. I'm going to set out my procedure as if you are a novice, but I am definitely not assuming that you actually are one. Some folks that may be tempted to try this procedure may be. First, I used kerosene liberally overnight to soak all of the threads inside and out (it is the 'active' ingrdient of many rust solvents). I also made arrangements with the yard for an emergency haulout if things went sour. I had an emergency bung ready, all parts prepared, batteries charged, pumps ready and crossed my fingers. It is very important that your new valve does not have tapered pipe threads. Through hulls have British straight threads and a pipe valve will not seal without undue pressure...and even then, you will only have about three threads engaged, making a very vulnerable joint. I installed about two feet of hose on the inboard side of the valve and opened it fully. I then snugged down the nut on the throuh hull fitting (and was surprised to find that it would actually tighten a little). As others have noted, you will want to be very careful not to turn the body of the through hull. Leave a wrench on the nut when removing and replacing valves in order to help prevent the through hull from turning and to keep from damaging the threads by putting a wrench on the body of the through hull fitting. I was able to wedge that wrench against a bulkhead, freeing both hands. Next, is a trick that I learned in my youth while working with a steamfitter. Tighten...yes...tighten...the old valve with a smart rap of a hammer on the end of the handle of the wrench. This is the most effective way of loosening an old thread that I have ever learned. You will likely need to reverse the wrench on the nut if you are using a pipe wrench. The old valve should now come off easily. As you get near the end of the threads, water will start coming in with increasing pressure. Don't panic...it is far less volume than it would appear. When the old valve comes free, pop the bung in the through hull and take a deep breath. Reverse the wrench on the through hull nut again and ready the new valve. The purpose of the hose and open valve is to reduce water pressure while threading on the new valve. The hose should extend above the water line. As soon as the valve and fitting make contact, very little force is required to keep the leaking down to a minimum. This allows you to thread on the valve easily without cross-threading. When the valve is screwed down all the way, it doesn't require a lot of torque to fully tighten it...so don't overdo it. I doubt that I took on more than a half a gollon of water in the process and have had no problems since.
I did it in the water on my 30-year old Cal's OEM 1-1/4" head discharge a couple of years ago. I had no problems but proceeded with much caution and a certain amount of trepidation. I'm going to set out my procedure as if you are a novice, but I am definitely not assuming that you actually are one. Some folks that may be tempted to try this procedure may be. First, I used kerosene liberally overnight to soak all of the threads inside and out (it is the 'active' ingrdient of many rust solvents). I also made arrangements with the yard for an emergency haulout if things went sour. I had an emergency bung ready, all parts prepared, batteries charged, pumps ready and crossed my fingers. It is very important that your new valve does not have tapered pipe threads. Through hulls have British straight threads and a pipe valve will not seal without undue pressure...and even then, you will only have about three threads engaged, making a very vulnerable joint. I installed about two feet of hose on the inboard side of the valve and opened it fully. I then snugged down the nut on the throuh hull fitting (and was surprised to find that it would actually tighten a little). As others have noted, you will want to be very careful not to turn the body of the through hull. Leave a wrench on the nut when removing and replacing valves in order to help prevent the through hull from turning and to keep from damaging the threads by putting a wrench on the body of the through hull fitting. I was able to wedge that wrench against a bulkhead, freeing both hands. Next, is a trick that I learned in my youth while working with a steamfitter. Tighten...yes...tighten...the old valve with a smart rap of a hammer on the end of the handle of the wrench. This is the most effective way of loosening an old thread that I have ever learned. You will likely need to reverse the wrench on the nut if you are using a pipe wrench. The old valve should now come off easily. As you get near the end of the threads, water will start coming in with increasing pressure. Don't panic...it is far less volume than it would appear. When the old valve comes free, pop the bung in the through hull and take a deep breath. Reverse the wrench on the through hull nut again and ready the new valve. The purpose of the hose and open valve is to reduce water pressure while threading on the new valve. The hose should extend above the water line. As soon as the valve and fitting make contact, very little force is required to keep the leaking down to a minimum. This allows you to thread on the valve easily without cross-threading. When the valve is screwed down all the way, it doesn't require a lot of torque to fully tighten it...so don't overdo it. I doubt that I took on more than a half a gollon of water in the process and have had no problems since.
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