Every book I've read that touches on the subject of hull-throughs treat gate valves as the worst possible thing you could have in your boat. But the gate valves on my 1981 Hunter 27 are still working perfectly well after 24 years (as are the sea cocks). Either I'm really lucky or gate valves are not as bad as they are made out to be. In my reading, I've come across several accounts of sea cocks freezing or failing, but never a gate valve. I'm not saying gate valves are better than sea cocks -- you still have the problem of not being able to visually tell if they are open or closed, but where's the evidence that they are less reliable? Sure, if I were starting from scratch I would probably avoid them, but given their performance to date, I see no reason to replace them. So here's my question: Has anybody had first-hand experience with a gate valve failing and, if so, under what conditions?
Gate valves - bad rap?
- Thread starter Stephen OBrien
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insurance
Most of the insurers now require that gate valves be replaced with Ball valves. The concern is that the gate valve can have an impediment impede it's abilty to close completely. It is an old technology but like the dodo bird......
Most of the insurers now require that gate valves be replaced with Ball valves. The concern is that the gate valve can have an impediment impede it's abilty to close completely. It is an old technology but like the dodo bird......
Gate Valves
Unlike ball valves, gate valves can easily be held open by small debree as simple as a twig. You will not know that you have problem until a hose breaks and you attempt to close the valve, in the midst of water gushing into your baby. Replace them all quickly! Jon McClain
Unlike ball valves, gate valves can easily be held open by small debree as simple as a twig. You will not know that you have problem until a hose breaks and you attempt to close the valve, in the midst of water gushing into your baby. Replace them all quickly! Jon McClain
Thru hull Valves
I had them break on my h34. There is no way to determine visually whether they are open or closed. On mine the stem broke inside and once the valve was close it would never open but the knob kept turning. I changed them all to bronze ball valves and slept better
I had them break on my h34. There is no way to determine visually whether they are open or closed. On mine the stem broke inside and once the valve was close it would never open but the knob kept turning. I changed them all to bronze ball valves and slept better
Brass(?) Gate Valves
Some manufacturers (like my Catalina, and maybe your Hunter?) used to use garden variety BRASS gate valves. (Literally garden variety-they were made for your backyard faucet!) In salt water, brass corodes much quicker than the bronze or marelon that marine-grade thru-hulls, ball valves and seacocks are made from. The zinc in the brass can leach out without being at all obvious to the untrained eye, and severly weaken the body of the valve. When you try to turn the valve, and it breaks off in your hand, and the water pours in! After 24 years, if your gate valves are brass, and you're in salt water, I'd replace those puppies ASAP!!! But then, I'm in freshwater all but about 1 month a year, and I finally replaced my last gatevalves and thru hulls 3 years ago, and they were OK then. My Cat27 was 30 years old in 2004.
Some manufacturers (like my Catalina, and maybe your Hunter?) used to use garden variety BRASS gate valves. (Literally garden variety-they were made for your backyard faucet!) In salt water, brass corodes much quicker than the bronze or marelon that marine-grade thru-hulls, ball valves and seacocks are made from. The zinc in the brass can leach out without being at all obvious to the untrained eye, and severly weaken the body of the valve. When you try to turn the valve, and it breaks off in your hand, and the water pours in! After 24 years, if your gate valves are brass, and you're in salt water, I'd replace those puppies ASAP!!! But then, I'm in freshwater all but about 1 month a year, and I finally replaced my last gatevalves and thru hulls 3 years ago, and they were OK then. My Cat27 was 30 years old in 2004.
a documented experience on a Hunter 54
about 4-6 months ago there was a Hunter 54 listed on ebay for sale... this largest of the Cherubini designs had sailed from Louisiana i believe and made it to Key West at Key West it sank at the dock due to faulty valves and was recovered legitimate seacocks are preferred by some and ball valves by others either are MUCH BETTER than gate valves sailorhayes@hotmail.com
about 4-6 months ago there was a Hunter 54 listed on ebay for sale... this largest of the Cherubini designs had sailed from Louisiana i believe and made it to Key West at Key West it sank at the dock due to faulty valves and was recovered legitimate seacocks are preferred by some and ball valves by others either are MUCH BETTER than gate valves sailorhayes@hotmail.com
In response...
Is there only one reader out there who has experienced a failure first hand? Let me offer the following comments: 1) Briann: If insurers are not writing policies for boats with gate valves then there must be a lot of uninsured boats out there. My boat is insured and it has gate valves. 2) Fred: I'm not saying sea cocks are not preferable, I'm simply saying that the perceived danger from gate valves is way exaggerated. 3) Jon: No valve will close if obstructed. 4) Daryl: Yours is an excellent example. Again, I'm not saing gate valves won't fail or that they are better than ball valves, but how much worse are they? In his book "This Old Boat" Don Casey demonizes gate valves but in the entire book the only example of a valve failure he offers is a ball valve that corroded and came off in his hand! 5) Peter: Excellent point, inferior construction of any boat component is a bad thing. But, are all gate valves made so poorly? If so, how come we don't hear about their failure every day given the large number of boats that employ them? 6) SailorHayes: Do we know that the valve that failed on the 54 was a gate valve?
Is there only one reader out there who has experienced a failure first hand? Let me offer the following comments: 1) Briann: If insurers are not writing policies for boats with gate valves then there must be a lot of uninsured boats out there. My boat is insured and it has gate valves. 2) Fred: I'm not saying sea cocks are not preferable, I'm simply saying that the perceived danger from gate valves is way exaggerated. 3) Jon: No valve will close if obstructed. 4) Daryl: Yours is an excellent example. Again, I'm not saing gate valves won't fail or that they are better than ball valves, but how much worse are they? In his book "This Old Boat" Don Casey demonizes gate valves but in the entire book the only example of a valve failure he offers is a ball valve that corroded and came off in his hand! 5) Peter: Excellent point, inferior construction of any boat component is a bad thing. But, are all gate valves made so poorly? If so, how come we don't hear about their failure every day given the large number of boats that employ them? 6) SailorHayes: Do we know that the valve that failed on the 54 was a gate valve?
US Navy
When I was in the Navy I had to do maintenence on a lot a valves on the ship. 90% were gate valves. I don't think I ever saw a failure in one of them. Just in my section there was over 100 valves.
When I was in the Navy I had to do maintenence on a lot a valves on the ship. 90% were gate valves. I don't think I ever saw a failure in one of them. Just in my section there was over 100 valves.
Frozen Gate Valves
Hi, Stephen. Before buying our Hunter 340 we sailed club boats out of Boston Harbor. We mostly sailed 28 foot Albins, and they all had gate valves on the thru-hulls, and essentially every one of them was frozen or the stem broken in the open position. As for "failure", it depends at least a bit on what you call "failure". We never had one of the valves "fail" on us in the sense of breaking and resulting in the boat flooding, but if we ever had to close one of these valves, we would have been SOL; they had definitely "failed" to be able to perform their intended function!The basic design of gate valves is prone to stem breakage and gate freezing for any of several reasons. You asked for input on gate valves, and the direction of that input seems pretty consistent. As always, it's your choice. Carl s/v Syzygy
Hi, Stephen. Before buying our Hunter 340 we sailed club boats out of Boston Harbor. We mostly sailed 28 foot Albins, and they all had gate valves on the thru-hulls, and essentially every one of them was frozen or the stem broken in the open position. As for "failure", it depends at least a bit on what you call "failure". We never had one of the valves "fail" on us in the sense of breaking and resulting in the boat flooding, but if we ever had to close one of these valves, we would have been SOL; they had definitely "failed" to be able to perform their intended function!The basic design of gate valves is prone to stem breakage and gate freezing for any of several reasons. You asked for input on gate valves, and the direction of that input seems pretty consistent. As always, it's your choice. Carl s/v Syzygy
Bad maintenance
I strongly believe that any frozen valve -- gate or ball -- is the result of bad maintenance. I doubt that one in 100 owners takes the time to lubricate any of their valves. A badly maintained ball valve is slightly less likely to freeze as a badly maintained gate valve, but not that much less. (unless, of course, it's one of the newer "plastic" ones, which beat all others)
I strongly believe that any frozen valve -- gate or ball -- is the result of bad maintenance. I doubt that one in 100 owners takes the time to lubricate any of their valves. A badly maintained ball valve is slightly less likely to freeze as a badly maintained gate valve, but not that much less. (unless, of course, it's one of the newer "plastic" ones, which beat all others)
about those valves
The trick with the gate valves is to be gentle with them. You don't need to tighten them down until you can't move it, thats why they fail. It only needs to be barley snug for a good seal. Same goes for opening, when you feel resistance ...stop, its open. I worked at a local yard for a year (commercial shrimp boats) and all the bad valves we replaced were stripped from too much force. Also, no matter what kind of valve you have you should have a plug tied to it, ready to be pounded in if something goes wrong.
The trick with the gate valves is to be gentle with them. You don't need to tighten them down until you can't move it, thats why they fail. It only needs to be barley snug for a good seal. Same goes for opening, when you feel resistance ...stop, its open. I worked at a local yard for a year (commercial shrimp boats) and all the bad valves we replaced were stripped from too much force. Also, no matter what kind of valve you have you should have a plug tied to it, ready to be pounded in if something goes wrong.
Construction, Not Maintenance
Stephen and others, The difference between the valves is the amount of material inside the valve that is exposed to whatever is in the piping / hoses. The gate valve has a stem that pushes the plate into the cavity. That stem is in contact with the material (water, waste, etc.) inside the hose/pipe. So in addition to the plate getting stuck and not closing completely, the stem can and does rot out. That's why the gate valves' handles sometimes turn but nothing happens. The ball valve's stem is not exposed to the stuff inside. For those of you who may be unfamiliar with the different types of valves: Go to a hardware store and take a look at a ball valve and a gate valve, play with them and see how they work. Grab a pair of pliers and take the bonnet off and look inside. While they're not bronze (in the hardware store, just brass for plumbing) the way different types of vales work is the same regardless of the material they are made of. It'll take a lot of the mystery out of this discussion. In any event, using the valve on a regular basis will extend its life. Any valve left in one position all the time is subject to freezing up and not working. Since ball vales are easier to oepn and close, its a no-brainer to use them. The one gate valve I have on my boat requires 55 quarter turns to gt it open from a closed position. Guess how often I do that! Stu
Stephen and others, The difference between the valves is the amount of material inside the valve that is exposed to whatever is in the piping / hoses. The gate valve has a stem that pushes the plate into the cavity. That stem is in contact with the material (water, waste, etc.) inside the hose/pipe. So in addition to the plate getting stuck and not closing completely, the stem can and does rot out. That's why the gate valves' handles sometimes turn but nothing happens. The ball valve's stem is not exposed to the stuff inside. For those of you who may be unfamiliar with the different types of valves: Go to a hardware store and take a look at a ball valve and a gate valve, play with them and see how they work. Grab a pair of pliers and take the bonnet off and look inside. While they're not bronze (in the hardware store, just brass for plumbing) the way different types of vales work is the same regardless of the material they are made of. It'll take a lot of the mystery out of this discussion. In any event, using the valve on a regular basis will extend its life. Any valve left in one position all the time is subject to freezing up and not working. Since ball vales are easier to oepn and close, its a no-brainer to use them. The one gate valve I have on my boat requires 55 quarter turns to gt it open from a closed position. Guess how often I do that! Stu
First hand experience of failure
About two years ago, I had a failure of one of the original bronze gate valves on my 1980 Hunter 30. After twenty two years of exposure to salt and brackish water in coastal New Jersey, the gate valve on the drain line for the galley sink gave it up. The valve failed in the closed position (fortunately)so that the sliding plate became frozen in place and detatched itself from the screw shaft. The other gate valve on the boat, for the head discharge continued to function. I put pictures in the HOW Photo Forum of both valves.
About two years ago, I had a failure of one of the original bronze gate valves on my 1980 Hunter 30. After twenty two years of exposure to salt and brackish water in coastal New Jersey, the gate valve on the drain line for the galley sink gave it up. The valve failed in the closed position (fortunately)so that the sliding plate became frozen in place and detatched itself from the screw shaft. The other gate valve on the boat, for the head discharge continued to function. I put pictures in the HOW Photo Forum of both valves.
More First Hand Experience
I had a gate valve failure on my C22. It was jammed with debris and then the stem broke. This “emergency” required swapping out the valve while the boat was still in the water. That experience was a little like those submarine movies where a valve breaks… Needless to say it’s been ball valves for me ever since!
I had a gate valve failure on my C22. It was jammed with debris and then the stem broke. This “emergency” required swapping out the valve while the boat was still in the water. That experience was a little like those submarine movies where a valve breaks… Needless to say it’s been ball valves for me ever since!
Stephen, Why so Defensive?
My, My! Are we touchy today. We are talking about gate valves here; not your wife or girlfriend. I thought that the ability of a ball valve to better handle an incidental obstruction was obvious. I won't go into details, just set an example of each side by side and it will be obvious. Jon McClain
My, My! Are we touchy today. We are talking about gate valves here; not your wife or girlfriend. I thought that the ability of a ball valve to better handle an incidental obstruction was obvious. I won't go into details, just set an example of each side by side and it will be obvious. Jon McClain
Ball Valves and Sea Cocks
Note that all the ball valves I have ever seen have tapered pipe (NPT) threads and all of the thru hulls I have ever seen have straight pipe (NPS) threads. The thru hulls have straight threads so that they can be used on various thicknesses of hull. Although the pitch of the threads on ball valves and sea cocks is the same and you can screw a pipe threaded gate valve onto a straight threaded thru hull, only a couple of threads will be engaged. This condition is not good and is asking for dribble leaks and eventual failure. In addition, a ball valve sticking up on an unsupported thru hull is also looking for trouble as the thru hulls aren't that strong and a good kick or a blow from something heavy moving around in a sea way can damage or even break an unsupported thru hull/ball valve combination. Do the job right and attach a bronze thru hull to a bronze sea cock mounted on a sturdy backing block and bolted down so that it can't be unscrewed. The cost difference between ball valves and sea cocks of the same size is maybe ten bucks and you may have five or six of them in your boat. Do you really want to go with second best to save 50 or 60 bucks???
Note that all the ball valves I have ever seen have tapered pipe (NPT) threads and all of the thru hulls I have ever seen have straight pipe (NPS) threads. The thru hulls have straight threads so that they can be used on various thicknesses of hull. Although the pitch of the threads on ball valves and sea cocks is the same and you can screw a pipe threaded gate valve onto a straight threaded thru hull, only a couple of threads will be engaged. This condition is not good and is asking for dribble leaks and eventual failure. In addition, a ball valve sticking up on an unsupported thru hull is also looking for trouble as the thru hulls aren't that strong and a good kick or a blow from something heavy moving around in a sea way can damage or even break an unsupported thru hull/ball valve combination. Do the job right and attach a bronze thru hull to a bronze sea cock mounted on a sturdy backing block and bolted down so that it can't be unscrewed. The cost difference between ball valves and sea cocks of the same size is maybe ten bucks and you may have five or six of them in your boat. Do you really want to go with second best to save 50 or 60 bucks???
Ball Valves, and other strangers
What about Stainless Thru-Hulls and Stainless Ball Valves, I actually found a place on the web where you can get Stailess Ball Valves for $15 apiece for 1/2.
What about Stainless Thru-Hulls and Stainless Ball Valves, I actually found a place on the web where you can get Stailess Ball Valves for $15 apiece for 1/2.
Be careful with stainless in salt water
Bob, Be very careful in using stainless steel in salt water in an immersion situation and particularly in stagnent salt water. 316 stainless steel works well for deck fittings and other applications which allow it to dry off, but can be a problem in immersion service. A number of years ago, I worked on a project in Puerto Rico in which we used 316 stainless steel piping and valves in salt water service. Everything was fine as long as the water was flowing. After start-up, we shut the system down for a few weeks and did not drain it. On restart, we found that pinhole leaks had developed in the piping, which got worse and worse over time. The cause was a bacteria in the water which would eat its way through the stainless piping when the water was left stagnent. We had to replace the whole system with fiberglass!. There are special stainless steels which will work in salt water, but marine bronze is a much better choice.
Bob, Be very careful in using stainless steel in salt water in an immersion situation and particularly in stagnent salt water. 316 stainless steel works well for deck fittings and other applications which allow it to dry off, but can be a problem in immersion service. A number of years ago, I worked on a project in Puerto Rico in which we used 316 stainless steel piping and valves in salt water service. Everything was fine as long as the water was flowing. After start-up, we shut the system down for a few weeks and did not drain it. On restart, we found that pinhole leaks had developed in the piping, which got worse and worse over time. The cause was a bacteria in the water which would eat its way through the stainless piping when the water was left stagnent. We had to replace the whole system with fiberglass!. There are special stainless steels which will work in salt water, but marine bronze is a much better choice.
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