I'm getting to replace several badly corroded seacocks on my Hunter 30. What is the story on Marelon fittings. The seem like a good idea to me, since they won't corrode, but the folks at my yard say they don't trust them. Is that just "traditionalism" speaking? 2) Also, are Marelon seacocks and ball valves compatable with brass through-hulls? In other words if I go to Marelon valves, must I replace the through-hulls too? 3) Anybody done this job yourself? Is it difficult? Thanks
- Status
- Not open for further replies.
B
Brian Ranniger
I used them.
I replaced all of my thru-hulls (4) with the marelon variety. You'll get differing opinions from different people. I suppose I would use heavy bronze if I were an ocean cruiser, but for the occasional sailing I chose the marelon. One of my factory Catalina thru hulls gave out shortly after buying the boat (the surveyor could not tell it was bad, nor could I) and could have sunk it at the dock. Luckily I came out to work on it and heard the bilge pump going almost constantly. It was corroded from the inside from electrolysis. Anyway, I didn't want to ever worry about it again. The seacocks and ball valves are pretty substantial pieces of composite and seem pretty heavy duty.
I replaced all of my thru-hulls (4) with the marelon variety. You'll get differing opinions from different people. I suppose I would use heavy bronze if I were an ocean cruiser, but for the occasional sailing I chose the marelon. One of my factory Catalina thru hulls gave out shortly after buying the boat (the surveyor could not tell it was bad, nor could I) and could have sunk it at the dock. Luckily I came out to work on it and heard the bilge pump going almost constantly. It was corroded from the inside from electrolysis. Anyway, I didn't want to ever worry about it again. The seacocks and ball valves are pretty substantial pieces of composite and seem pretty heavy duty.
J
John J.
Marelon
If you look in the West Marine book you will see a couple of varities of these valves. One, they are not compatable with any metal through hull. Two, do not buy the "integrated" valve" they are mostly sold with new boats, but are not as substantial as the other Marelon valves.
If you look in the West Marine book you will see a couple of varities of these valves. One, they are not compatable with any metal through hull. Two, do not buy the "integrated" valve" they are mostly sold with new boats, but are not as substantial as the other Marelon valves.
T
Todd Osborne
I've used both
and all of the marelon valve handles broke off after a few years. reason: I did not regularly lubricate them. I replaced one bass valve because the handle corroded. So if you have corrosion concerns but are able to regularly service/lubricate the valves, marelon might not be bad, otherwise use brass.
and all of the marelon valve handles broke off after a few years. reason: I did not regularly lubricate them. I replaced one bass valve because the handle corroded. So if you have corrosion concerns but are able to regularly service/lubricate the valves, marelon might not be bad, otherwise use brass.
J
Jon Bastien
Just installed Marelon
I just installed Marelon seacocks on my boat. The yard used bronze thru-hulls and put the Marelon seacocks on them, using a little teflon tape and sealing the whole shebang with 5200. John J, Why is Marelon incompatible with any metal? According to the West advisor, (-Quote-) ...such as nylon or marelon, both of which we carry. These galvanically inert materials present no problems when used in conjunction with any marine metals in underwater applications. (-Unquote-) Is there something more that we need to know? Or is the danger primarily from stripping the threads on the non-metal part? As a side note, I replaced the old seacocks because they were corroded so badly that they were frozen open. They had been this way since I bought the boat. I am MUCH less concerned about this now, as a.) I leave the seacocks closed when not in use, and b.) I haul the boat once a year for maintenance/paint, and can lubricate the seacocks then. I guess I'll just have to be careful about forcing the handle... --Jon Bastien H25 'Adagio'
I just installed Marelon seacocks on my boat. The yard used bronze thru-hulls and put the Marelon seacocks on them, using a little teflon tape and sealing the whole shebang with 5200. John J, Why is Marelon incompatible with any metal? According to the West advisor, (-Quote-) ...such as nylon or marelon, both of which we carry. These galvanically inert materials present no problems when used in conjunction with any marine metals in underwater applications. (-Unquote-) Is there something more that we need to know? Or is the danger primarily from stripping the threads on the non-metal part? As a side note, I replaced the old seacocks because they were corroded so badly that they were frozen open. They had been this way since I bought the boat. I am MUCH less concerned about this now, as a.) I leave the seacocks closed when not in use, and b.) I haul the boat once a year for maintenance/paint, and can lubricate the seacocks then. I guess I'll just have to be careful about forcing the handle... --Jon Bastien H25 'Adagio'
G
Garry @ S/V TASHTEGO
THRU HULLS (again)
A lot of folks have had problems with Marelon sea cocks. Mostly frozen valves and broken handles. Buy quality bronze and sleep at night. Here are some things to remember: 1. Thru hulls are straight threaded. When marked they will say NPS for National Pipe Straight. This is because they must adapt to a wide range of hull thicknesses. A tapered thread always jams at the same place on the thread and can't adapt to varying thicknesses. 2. They must be mated to real thru hulls which also have NPS threads. 3. They should NOT be mated to ball valves which have tapered threads (NPT). 4. Its bronze not brass you want as brass will rot fast in sea water. 5. Doing it right (I've finally finished all four on TASHTEGO) is a pain. I did the last three (engine water inlet, head inlet and sink/icebox drain, all 3/4 inch)in a couple of hours each, working alone, but the big (1 1/2 inch) head outlet was very hard to do. 6. Make epoxy coated teak bases for each sea cock so that they are firmly mounted when screwed onto the thru hull. Don't leave them sticking up in the air without base support. If something hits them, all the stress goes onto the thru hull where the threads make a lovely crack initiator. 7. If you think you might someday want/have to do the job again - use 4200 not 5200. 8. Use plenty of teflon tape on the threads and you may be able to get them apart again if you ever need to.
A lot of folks have had problems with Marelon sea cocks. Mostly frozen valves and broken handles. Buy quality bronze and sleep at night. Here are some things to remember: 1. Thru hulls are straight threaded. When marked they will say NPS for National Pipe Straight. This is because they must adapt to a wide range of hull thicknesses. A tapered thread always jams at the same place on the thread and can't adapt to varying thicknesses. 2. They must be mated to real thru hulls which also have NPS threads. 3. They should NOT be mated to ball valves which have tapered threads (NPT). 4. Its bronze not brass you want as brass will rot fast in sea water. 5. Doing it right (I've finally finished all four on TASHTEGO) is a pain. I did the last three (engine water inlet, head inlet and sink/icebox drain, all 3/4 inch)in a couple of hours each, working alone, but the big (1 1/2 inch) head outlet was very hard to do. 6. Make epoxy coated teak bases for each sea cock so that they are firmly mounted when screwed onto the thru hull. Don't leave them sticking up in the air without base support. If something hits them, all the stress goes onto the thru hull where the threads make a lovely crack initiator. 7. If you think you might someday want/have to do the job again - use 4200 not 5200. 8. Use plenty of teflon tape on the threads and you may be able to get them apart again if you ever need to.
B
Brian Ranniger
Forgot to mention
If you use marelon, you are not supposed to use wood backing plates. I used polyethylene (sp?) The stuff they make cutting boards out of.
If you use marelon, you are not supposed to use wood backing plates. I used polyethylene (sp?) The stuff they make cutting boards out of.
Just a point.
Found this article on Sailnet. Maybe they are okay, maybe they're not! It is really not a matter of being set in our ways or being a traditionalist. It is a matter of which is really better. I would agree that plastics for tanks are the way to go but I am still not convinced that they are the way to go for below the water line thru hulls. Just another opinion!
Found this article on Sailnet. Maybe they are okay, maybe they're not! It is really not a matter of being set in our ways or being a traditionalist. It is a matter of which is really better. I would agree that plastics for tanks are the way to go but I am still not convinced that they are the way to go for below the water line thru hulls. Just another opinion!
D
David
Bronze - Marelon
For those interested, A.B.Y.C. in section H27 states minimum strength standards for both types of thru hulls. I believe these standards ( not opinions ) are available on the internet.
For those interested, A.B.Y.C. in section H27 states minimum strength standards for both types of thru hulls. I believe these standards ( not opinions ) are available on the internet.
J
John J.
Marelon
Jon, I was told by Forespar not to mate differing materials. I agree there should be no reaction between the two materials, my guess is they are more worried about stripping the threads. My situation came about because a handle broke off on a new fitting. The 310 comes with the integrated fittings and I asked if I could replace the valve with metal. The integrated fittings can only be repaired with exact replacemtnt parts. Anyone having a 310 built might want to ask to have a better fitting installed during construction.
Jon, I was told by Forespar not to mate differing materials. I agree there should be no reaction between the two materials, my guess is they are more worried about stripping the threads. My situation came about because a handle broke off on a new fitting. The 310 comes with the integrated fittings and I asked if I could replace the valve with metal. The integrated fittings can only be repaired with exact replacemtnt parts. Anyone having a 310 built might want to ask to have a better fitting installed during construction.
J
John J.
Marelon-one more time
Ron, I am aware that a marelon valve must be able to wtihstand 500lbs of pressure before breaking. However, when one snaps off in your hand with minimal pressure, and water starts pouring in, that is a whole different story. In my case this is first hand experience. I am sure many people never have any problem with these valves, but the sailing magazines and the internet have ample stories of documented problems with breakage. Each person has to weigh the advantages and disadvantages of metal vs. plastic, and what their sailing envorinment is. Based on that, each makes what they believe is the best choice for their needs.
Ron, I am aware that a marelon valve must be able to wtihstand 500lbs of pressure before breaking. However, when one snaps off in your hand with minimal pressure, and water starts pouring in, that is a whole different story. In my case this is first hand experience. I am sure many people never have any problem with these valves, but the sailing magazines and the internet have ample stories of documented problems with breakage. Each person has to weigh the advantages and disadvantages of metal vs. plastic, and what their sailing envorinment is. Based on that, each makes what they believe is the best choice for their needs.
- Status
- Not open for further replies.