This past weekend I was re-plumbing my head/holding tank system with a macerator pump and y-valve. After completing the job, I tried to open the seacock for the overboard discharge and the handle came off in my hand, twisting off the shaft inside the seacock. Is there a way to repair the seacock, or do I have to replace it at $75 a pop. I can see how I would remove it to repair or replace without a haul-out by plugging from the outside during removal. The thru-hull fitting is still in good shape, it's just the valve that needs attention. I have done some research about seacocks and ball valves and the difference is in the threads. The thru-hull fitting has straight threads and seacocks are built with the same threads and usually a flange for added strength. Looking at the valves below the waterline on my boat, they don't have a flange? Can I assume that Hunter used inline ball valves with tapered threads screwed onto a straight threaded thru hull fitting? Looking forward to any others with experience in thru-hulls on 1990 and later Hunter 335 Legends. Brent Headberg S/V Elena Lua
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Threads
I believe you are right about Hunter using tapered thread ball valves. From your description, you have gate valves right now. These are known freeze up. Around here people use ball valves, must be bronze, not brass. The trick shown to me was to gently file back the thru hull threads a few grooves, effectivly changing a taper into a straight thread.. I have done this and can get a good 7 full turns onto the thru hull (do this at your own risk). This is pretty standard practice around here. If I had to do it over again I would just go ahead and buy real seacocks. Peace of mind more than anything else. NO matter what you decide, replace the gate valves. You may want to remove the thru hull and reset it since you can loosen the caulk while removing the currrent valve. I would recommend using Lifecaulk and don't be stingy with the caulk. Good luck!
I believe you are right about Hunter using tapered thread ball valves. From your description, you have gate valves right now. These are known freeze up. Around here people use ball valves, must be bronze, not brass. The trick shown to me was to gently file back the thru hull threads a few grooves, effectivly changing a taper into a straight thread.. I have done this and can get a good 7 full turns onto the thru hull (do this at your own risk). This is pretty standard practice around here. If I had to do it over again I would just go ahead and buy real seacocks. Peace of mind more than anything else. NO matter what you decide, replace the gate valves. You may want to remove the thru hull and reset it since you can loosen the caulk while removing the currrent valve. I would recommend using Lifecaulk and don't be stingy with the caulk. Good luck!
Do yourself a favor
Replace the thru hull fittings too. There is no sense to not replace them, I did this last spring, and found the bedding compound was solidified, broke and powered when I removed the fittings. Don't take the chance!
Replace the thru hull fittings too. There is no sense to not replace them, I did this last spring, and found the bedding compound was solidified, broke and powered when I removed the fittings. Don't take the chance!
Galvanic Chart
Thanks for your input on replacing my seacocks. I haven't gone back to look at the valve that I broke the handle on, but I'm almost positive it's a ball valve, not a gate valve. This valve has a lever that rotates 1/4 turn. In any case, I've studied up on everyone's recomendation to replace with a bronze valve or marlite valve, but according to the galvanic chart and info shown in the related link below, it seems acceptable to use a brass valve on a bronze thru-hull fitting. I have discussed it with an experienced mechanical engineer about using a female tapered thread on a male straight thread, and he indicated that with the proper sealer (teflon tape or pipe joint material), it will seat properly, as long as you can thread the female onto the male at least 5 complete turns. My whole dilema in all of this is to feel comfortable with my choice and save some money at the same time. Here's the difference in cost: 1 1/2" Bronze Ball Valve 42.99 1 1/2" Bronze Seacock 79.99 1 1/2" Marelon Seacock 82.99 Home Depot Plumbing parts: 1 1/2" Brass Ball Valve 12.99 1 1/2" PVC Ball Valve 5.99 Although it's not much difference if you only preplace one, but my boat has 7 valves below the waterline. Being that I am in Florida and not bothered by cold weather, I am leaning towards the brass ball valve as a replacement. Please read the info on galvanic reaction on the link below:
Thanks for your input on replacing my seacocks. I haven't gone back to look at the valve that I broke the handle on, but I'm almost positive it's a ball valve, not a gate valve. This valve has a lever that rotates 1/4 turn. In any case, I've studied up on everyone's recomendation to replace with a bronze valve or marlite valve, but according to the galvanic chart and info shown in the related link below, it seems acceptable to use a brass valve on a bronze thru-hull fitting. I have discussed it with an experienced mechanical engineer about using a female tapered thread on a male straight thread, and he indicated that with the proper sealer (teflon tape or pipe joint material), it will seat properly, as long as you can thread the female onto the male at least 5 complete turns. My whole dilema in all of this is to feel comfortable with my choice and save some money at the same time. Here's the difference in cost: 1 1/2" Bronze Ball Valve 42.99 1 1/2" Bronze Seacock 79.99 1 1/2" Marelon Seacock 82.99 Home Depot Plumbing parts: 1 1/2" Brass Ball Valve 12.99 1 1/2" PVC Ball Valve 5.99 Although it's not much difference if you only preplace one, but my boat has 7 valves below the waterline. Being that I am in Florida and not bothered by cold weather, I am leaning towards the brass ball valve as a replacement. Please read the info on galvanic reaction on the link below:
Lean away!
Brent: I think you should lead away from Brass. There was a warning from Practical Sailor on exactly this issue back in 1997 regarding using brass valves. I will try to find the article and relay it to you. As far as the Marelon goes, I do not like the feeling of these handles when you open and close them. They seem to feel like they can break at any moment (just my opinion).
Brent: I think you should lead away from Brass. There was a warning from Practical Sailor on exactly this issue back in 1997 regarding using brass valves. I will try to find the article and relay it to you. As far as the Marelon goes, I do not like the feeling of these handles when you open and close them. They seem to feel like they can break at any moment (just my opinion).
False Savings
I had all my through hull fittings and ball valves replaced last October. When the yard pulled the through hull discharge for the grey water tank we found Hunter had drilled an oversize hole for the fitting. They had put in the fitting and filled the space with sealer and a plywood backer. It held for 18 years but I'm glad I did not try to twist the ball valve off the hull fitting while in the water. The yard plugged the hole and redrilled it the correct size for the fitting. Has Hunter corrected this sloppy work? I hope so but you don't know for sure until you look. Now, are you sure you want to use CHEAP ball valves now and possible lose your boat in a couple of years? Or do you want to spend the money now (I know it hurts the pocket book) and sleep better? BTW, I'm in FLorida too and my boat stays in the water all year long so I chose to spend the money up front.
I had all my through hull fittings and ball valves replaced last October. When the yard pulled the through hull discharge for the grey water tank we found Hunter had drilled an oversize hole for the fitting. They had put in the fitting and filled the space with sealer and a plywood backer. It held for 18 years but I'm glad I did not try to twist the ball valve off the hull fitting while in the water. The yard plugged the hole and redrilled it the correct size for the fitting. Has Hunter corrected this sloppy work? I hope so but you don't know for sure until you look. Now, are you sure you want to use CHEAP ball valves now and possible lose your boat in a couple of years? Or do you want to spend the money now (I know it hurts the pocket book) and sleep better? BTW, I'm in FLorida too and my boat stays in the water all year long so I chose to spend the money up front.
Bronze Seacocks
Brent Go to the link below and you can buy the 1 1/2" seacock for $57.94, 1 1/4" for $40.00. Just replaced all my ball valves with seacocks and am glad I did. I tried the threads on the ball valves with the through hull and only 3 full threads were holding of the 5, recommend seacocks and so do most surveyors. Good luck! Jim http://www.boatfix.com/bykeyword.ASP?keyword=seacock&B18=Search
Brent Go to the link below and you can buy the 1 1/2" seacock for $57.94, 1 1/4" for $40.00. Just replaced all my ball valves with seacocks and am glad I did. I tried the threads on the ball valves with the through hull and only 3 full threads were holding of the 5, recommend seacocks and so do most surveyors. Good luck! Jim http://www.boatfix.com/bykeyword.ASP?keyword=seacock&B18=Search
It aint' worth it
I am agast that a degreed mechanical engineer would say it's ok to marry tapered to straight threads. It's not. At the intersection of the straight and tapered threads...the male and female threads do not align properly and WILL eventually fail. The other person who posted here is correct: the net surface area engaged by this arrangement is only 3-4 threads maximum. It's in the math. And overtightening to try and compensate doesn't change the thread count, it just increases the load on the few threads you are using. Because of the load put on those 3 threads, they will eventually give way without warning. The more you overtighten the faster they will fail. Trying to file the taper away as suggested won't increase the thread count - only by filing down the taper, you hasten disaster. It has to do with the surface area of the angle of the thread, but I will not bore you with the technical mumbo jumbo as to the nature of interlocking threads and how they work in conjunction. But I am advising you on the strongest terms not to do this. I also agree that if you have to replace the seacock, then you should rebed the thru-hull. In my own experience, the thru-hull usually shifted a bit as I worked the seacock off (I replaced all my gate valves with seacocks last season). This compromises the watertight seal of the thru-hull. Safest course is to use bona-fide seacocks and re-bed the thru-hulls. Good Luck. Mike
I am agast that a degreed mechanical engineer would say it's ok to marry tapered to straight threads. It's not. At the intersection of the straight and tapered threads...the male and female threads do not align properly and WILL eventually fail. The other person who posted here is correct: the net surface area engaged by this arrangement is only 3-4 threads maximum. It's in the math. And overtightening to try and compensate doesn't change the thread count, it just increases the load on the few threads you are using. Because of the load put on those 3 threads, they will eventually give way without warning. The more you overtighten the faster they will fail. Trying to file the taper away as suggested won't increase the thread count - only by filing down the taper, you hasten disaster. It has to do with the surface area of the angle of the thread, but I will not bore you with the technical mumbo jumbo as to the nature of interlocking threads and how they work in conjunction. But I am advising you on the strongest terms not to do this. I also agree that if you have to replace the seacock, then you should rebed the thru-hull. In my own experience, the thru-hull usually shifted a bit as I worked the seacock off (I replaced all my gate valves with seacocks last season). This compromises the watertight seal of the thru-hull. Safest course is to use bona-fide seacocks and re-bed the thru-hulls. Good Luck. Mike
Bite the bullet
I'm having the gate valves in my '85 H-34 replaced with the best quality genuine seacocks I can buy this fall. I only have 5 but I know it's going to be big bucks for each. My sleep equity is more important to me. I also reason that this is a one-time investment, cheap compared to annual insurance premiums, storage, etc when you amortize it over the life of the boat. Play it safe. do it right! Cut corners on things that don't have such potentially catastrophic consequences.
I'm having the gate valves in my '85 H-34 replaced with the best quality genuine seacocks I can buy this fall. I only have 5 but I know it's going to be big bucks for each. My sleep equity is more important to me. I also reason that this is a one-time investment, cheap compared to annual insurance premiums, storage, etc when you amortize it over the life of the boat. Play it safe. do it right! Cut corners on things that don't have such potentially catastrophic consequences.
Thru-Hulls/Hunter Engineers
There seems to be a lot of controversy about thru-hulls and seacocks and how to replace the original equipment below the waterline of Hunter sailboats. I can't imagine any engineer at the Hunter factory specifying something that would risk their integrity...seems that most later model Hunters have used the in-line ball valve with the tapered thread installed on a straight thread thru-hull. My 33.5 is now 12 years old and the only thing that's failed on these valves are the steel handles. I have read a lot about the reasons why the handles are designed to fail, it let's the owner know they need to be replaced. I guess it will remain a controversial subject about proper thru-hull equipment. I'm still not sure I agree with either side of the coin yet. Capn' Brent S/V Elena Lua
There seems to be a lot of controversy about thru-hulls and seacocks and how to replace the original equipment below the waterline of Hunter sailboats. I can't imagine any engineer at the Hunter factory specifying something that would risk their integrity...seems that most later model Hunters have used the in-line ball valve with the tapered thread installed on a straight thread thru-hull. My 33.5 is now 12 years old and the only thing that's failed on these valves are the steel handles. I have read a lot about the reasons why the handles are designed to fail, it let's the owner know they need to be replaced. I guess it will remain a controversial subject about proper thru-hull equipment. I'm still not sure I agree with either side of the coin yet. Capn' Brent S/V Elena Lua
Thru-Hulls/Hunter Engineers
There seems to be a lot of controversy about thru-hulls and seacocks and how to replace the original equipment below the waterline of Hunter sailboats. I can't imagine any engineer at the Hunter factory specifying something that would risk their integrity...seems that most later model Hunters have used the in-line ball valve with the tapered thread installed on a straight thread thru-hull. My 33.5 is now 12 years old and the only thing that's failed on these valves are the steel handles. I have read a lot about the reasons why the handles are designed to fail, it let's the owner know they need to be replaced. I guess it will remain a controversial subject about proper thru-hull equipment. I'm still not sure I agree with either side of the coin yet. Capn' Brent S/V Elena Lua
There seems to be a lot of controversy about thru-hulls and seacocks and how to replace the original equipment below the waterline of Hunter sailboats. I can't imagine any engineer at the Hunter factory specifying something that would risk their integrity...seems that most later model Hunters have used the in-line ball valve with the tapered thread installed on a straight thread thru-hull. My 33.5 is now 12 years old and the only thing that's failed on these valves are the steel handles. I have read a lot about the reasons why the handles are designed to fail, it let's the owner know they need to be replaced. I guess it will remain a controversial subject about proper thru-hull equipment. I'm still not sure I agree with either side of the coin yet. Capn' Brent S/V Elena Lua
Terminology
There seems to be some confusion about just what is a seacock vs. a ball valve. Jim's link shows a whole bunch of valves purported to be seacocks but which are just ball valves. Read the description. If it talks about a stainless steel ball connected to a handle it is a ball valve. I tried a search and found that virtually every reference to a seacock was actually a ball valve. There are very few real seacocks in use on any recently manufactured production boat. If you want to see a seacock try the link below. The valve is a slightly tapered solid bronze cone that fits into a correspondingly tapered solid bronze valve body connected to a handle. The cone is fastened, generally on one end, to a bolt or bolts that allow it to be adjusted. This determines how tight it rides inside the tapered hole and how much it leaks. There is no plastic valve seat keeping out the water, only solid bronze. It looks like a large version of the glass petcock valve on the acid carboy used in your high school chemistry lab. They generally cost about $400 to $500 per valve and are generally in the 2-3 inch variety. Island Packet and Sabre use them but not Hunter. If you are going to replace gate valves with ball valves, good for you, but discussing changing one ball valve for another is not the same as changing to real seacocks. Les s/v Mutual Fun
There seems to be some confusion about just what is a seacock vs. a ball valve. Jim's link shows a whole bunch of valves purported to be seacocks but which are just ball valves. Read the description. If it talks about a stainless steel ball connected to a handle it is a ball valve. I tried a search and found that virtually every reference to a seacock was actually a ball valve. There are very few real seacocks in use on any recently manufactured production boat. If you want to see a seacock try the link below. The valve is a slightly tapered solid bronze cone that fits into a correspondingly tapered solid bronze valve body connected to a handle. The cone is fastened, generally on one end, to a bolt or bolts that allow it to be adjusted. This determines how tight it rides inside the tapered hole and how much it leaks. There is no plastic valve seat keeping out the water, only solid bronze. It looks like a large version of the glass petcock valve on the acid carboy used in your high school chemistry lab. They generally cost about $400 to $500 per valve and are generally in the 2-3 inch variety. Island Packet and Sabre use them but not Hunter. If you are going to replace gate valves with ball valves, good for you, but discussing changing one ball valve for another is not the same as changing to real seacocks. Les s/v Mutual Fun
Terminology
There seems to be some confusion about just what is a seacock vs. a ball valve. Jim's link shows a whole bunch of valves purported to be seacocks but which are just ball valves. Read the description. If it talks about a stainless steel ball connected to a handle it is a ball valve. I tried a search and found that virtually every reference to a seacock was actually a ball valve. There are very few real seacocks in use on any recently manufactured production boat. If you want to see a seacock try the link below. The valve is a slightly tapered solid bronze cone that fits into a correspondingly tapered solid bronze valve body connected to a handle. The cone is fastened, generally on one end, to a bolt or bolts that allow it to be adjusted. This determines how tight it rides inside the tapered hole and how much it leaks. There is no plastic valve seat keeping out the water, only solid bronze. It looks like a large version of the glass petcock valve on the acid carboy used in your high school chemistry lab. They generally cost about $400 to $500 per valve and are generally in the 2-3 inch variety. Island Packet and Sabre use them but not Hunter. If you are going to replace gate valves with ball valves, good for you, but discussing changing one ball valve for another is not the same as changing to real seacocks. Les s/v Mutual Fun
There seems to be some confusion about just what is a seacock vs. a ball valve. Jim's link shows a whole bunch of valves purported to be seacocks but which are just ball valves. Read the description. If it talks about a stainless steel ball connected to a handle it is a ball valve. I tried a search and found that virtually every reference to a seacock was actually a ball valve. There are very few real seacocks in use on any recently manufactured production boat. If you want to see a seacock try the link below. The valve is a slightly tapered solid bronze cone that fits into a correspondingly tapered solid bronze valve body connected to a handle. The cone is fastened, generally on one end, to a bolt or bolts that allow it to be adjusted. This determines how tight it rides inside the tapered hole and how much it leaks. There is no plastic valve seat keeping out the water, only solid bronze. It looks like a large version of the glass petcock valve on the acid carboy used in your high school chemistry lab. They generally cost about $400 to $500 per valve and are generally in the 2-3 inch variety. Island Packet and Sabre use them but not Hunter. If you are going to replace gate valves with ball valves, good for you, but discussing changing one ball valve for another is not the same as changing to real seacocks. Les s/v Mutual Fun
So Les, you are saying. . .
that my seacocks(see Related Link) are NOT seacocks? And that is because they contain a ball valve? And after all that work!
that my seacocks(see Related Link) are NOT seacocks? And that is because they contain a ball valve? And after all that work!
So Les, you are saying. . .
that my seacocks(see Related Link) are NOT seacocks? And that is because they contain a ball valve? And after all that work!
that my seacocks(see Related Link) are NOT seacocks? And that is because they contain a ball valve? And after all that work!
Hey, Brent: The Thro-hulls Are NPT
I bet. I was looking at Ed's post and the through-hulls shown are NPT as are the ball valves. Also interestingly, the ball valves say not to use them as seacocks. However, the only difference appears to be the flange (or lack of) for direct hull mounting. Maybe that's the broader definition of seacock? Rick D.
I bet. I was looking at Ed's post and the through-hulls shown are NPT as are the ball valves. Also interestingly, the ball valves say not to use them as seacocks. However, the only difference appears to be the flange (or lack of) for direct hull mounting. Maybe that's the broader definition of seacock? Rick D.
Hey, Brent: The Thro-hulls Are NPT
I bet. I was looking at Ed's post and the through-hulls shown are NPT as are the ball valves. Also interestingly, the ball valves say not to use them as seacocks. However, the only difference appears to be the flange (or lack of) for direct hull mounting. Maybe that's the broader definition of seacock? Rick D.
I bet. I was looking at Ed's post and the through-hulls shown are NPT as are the ball valves. Also interestingly, the ball valves say not to use them as seacocks. However, the only difference appears to be the flange (or lack of) for direct hull mounting. Maybe that's the broader definition of seacock? Rick D.
Valves ?
Ed, The valve on the left in your link is a ball valve. The references that I found in the BoatUS pages reference Apollo ball valves. Each of the 4 Mfg #s and Item #s relate to Apollo Ball valves made by Conbraco. The valve on the right in your link looks like a seacock. You can see the horizontal tapered cone that goes through the body and the nut on the back end that adjusts the cone. That makes it a seacock. However none of the numbers relate to this valve. Not sure how you would order the valve on the right, or how much it would cost. But I don't think you would get the seacock on the right using the ball valve numbers in the link. And I don't think you could get it for that price. Also, note that the valve bodies and the backing flange look like they are a single piece. You would have to replace all of your thru hulls to use the valves in your link. You can usually find the valve separate from the flange. Thats where the issue of the tapered vs straight threads becomes an issue. Confusing, huh? Good luck which ever way you go. If you do find real seacocks at a reasonable $ I would like to know. I want to replace mine also. Les s/v Mutual Fun
Ed, The valve on the left in your link is a ball valve. The references that I found in the BoatUS pages reference Apollo ball valves. Each of the 4 Mfg #s and Item #s relate to Apollo Ball valves made by Conbraco. The valve on the right in your link looks like a seacock. You can see the horizontal tapered cone that goes through the body and the nut on the back end that adjusts the cone. That makes it a seacock. However none of the numbers relate to this valve. Not sure how you would order the valve on the right, or how much it would cost. But I don't think you would get the seacock on the right using the ball valve numbers in the link. And I don't think you could get it for that price. Also, note that the valve bodies and the backing flange look like they are a single piece. You would have to replace all of your thru hulls to use the valves in your link. You can usually find the valve separate from the flange. Thats where the issue of the tapered vs straight threads becomes an issue. Confusing, huh? Good luck which ever way you go. If you do find real seacocks at a reasonable $ I would like to know. I want to replace mine also. Les s/v Mutual Fun
Valves ?
Ed, The valve on the left in your link is a ball valve. The references that I found in the BoatUS pages reference Apollo ball valves. Each of the 4 Mfg #s and Item #s relate to Apollo Ball valves made by Conbraco. The valve on the right in your link looks like a seacock. You can see the horizontal tapered cone that goes through the body and the nut on the back end that adjusts the cone. That makes it a seacock. However none of the numbers relate to this valve. Not sure how you would order the valve on the right, or how much it would cost. But I don't think you would get the seacock on the right using the ball valve numbers in the link. And I don't think you could get it for that price. Also, note that the valve bodies and the backing flange look like they are a single piece. You would have to replace all of your thru hulls to use the valves in your link. You can usually find the valve separate from the flange. Thats where the issue of the tapered vs straight threads becomes an issue. Confusing, huh? Good luck which ever way you go. If you do find real seacocks at a reasonable $ I would like to know. I want to replace mine also. Les s/v Mutual Fun
Ed, The valve on the left in your link is a ball valve. The references that I found in the BoatUS pages reference Apollo ball valves. Each of the 4 Mfg #s and Item #s relate to Apollo Ball valves made by Conbraco. The valve on the right in your link looks like a seacock. You can see the horizontal tapered cone that goes through the body and the nut on the back end that adjusts the cone. That makes it a seacock. However none of the numbers relate to this valve. Not sure how you would order the valve on the right, or how much it would cost. But I don't think you would get the seacock on the right using the ball valve numbers in the link. And I don't think you could get it for that price. Also, note that the valve bodies and the backing flange look like they are a single piece. You would have to replace all of your thru hulls to use the valves in your link. You can usually find the valve separate from the flange. Thats where the issue of the tapered vs straight threads becomes an issue. Confusing, huh? Good luck which ever way you go. If you do find real seacocks at a reasonable $ I would like to know. I want to replace mine also. Les s/v Mutual Fun
Oversimplified?
Maybe I oversimplified. I bought both the thru-hull(straight threads) and the "seacock" at the same time. It looks like the one on the left in my previous post. I did notice the "NPT" but believe that is a typo. I have another one to install sitting on the boat and will check this weekend. I can tell you that the body screws all the way down onto the thru-hull. Well at least to the end of the threads in the body. The reason that I bought both the thru-hull and seacock as a package is due to size. On my H37C the engine and head thru-hulls are 3/4" and I could not find a "seacock" to fit. The new ones are bigger, 1 1/4" maybe? I know I have to fill the old hole and redrill to install. I also know about tapered versus straight threads. I have a ball valve on a thru-hull right now. If it is not REAL tight it leaks. And when you get it REAL tight the handle is likely to be where you cannot open and close it. But I have not had the problem of only getting three or four threads.
Maybe I oversimplified. I bought both the thru-hull(straight threads) and the "seacock" at the same time. It looks like the one on the left in my previous post. I did notice the "NPT" but believe that is a typo. I have another one to install sitting on the boat and will check this weekend. I can tell you that the body screws all the way down onto the thru-hull. Well at least to the end of the threads in the body. The reason that I bought both the thru-hull and seacock as a package is due to size. On my H37C the engine and head thru-hulls are 3/4" and I could not find a "seacock" to fit. The new ones are bigger, 1 1/4" maybe? I know I have to fill the old hole and redrill to install. I also know about tapered versus straight threads. I have a ball valve on a thru-hull right now. If it is not REAL tight it leaks. And when you get it REAL tight the handle is likely to be where you cannot open and close it. But I have not had the problem of only getting three or four threads.
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