I came across a knockoff Marelon on my raw water intake. Upon looking them up I discovered that there are Marelon sea cocks and ball valves. What the advantage and disadvantage of each? Aside from lubricating and excersizing, is there anything I should check on the rest of the ball valves to see their integrity?
Marelon Ball Valve VS Marelon Sea Cocks
- Thread starter Project_Mayhem
- Start date
The Marelon seacock has a flange against the hull which greatly increases the force required to break the thru-hull. The seacocks exceed the ABYC requirement to not break when subjected to a 500-lb load at the end of the fitting. My 88 C30 came from the factory with Marelon ball valves, and I replace all of them with the Marelon Seacocks.
Forespar Marelon OEM / 93 Series Destructive Testing
Forespar Marelon OEM / 93 Series Destructive Testing
Thanks for the clarification. Mine has the same. I'm ok with the marelon valves but it's the plastic through hulls that make me uncomfortable. I suppose if I switch to sea cocks, that'd make it significantly stronger. I swear my next boat will be something that was built right from the start such as a Sabre
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,353
I admire your belief that there is a boat built "Right." I think you may need to build the boat yourself.
Then, all you need to worry about are the plans. They are never wrong—ask any naval architect.
With a quarter century of experience with Sabre, let me disabuse you of that notion. Make no mistake, when it comes to design, joinery, and hull and rig construction there are few production boats that compete with them on build quality, that's why they were at the high end of the market and continue to hold their value. However, every Sabre owner will tell you they did a few things there were not so well thought out or built. None however, significantly compromised the safety or enjoyment of the boat, except when trying to deal with a few of their construction decisions, the enjoyment scale is real low when hanging upside down in a tight lazarette trying free an exhaust hose that had a zip tie buried under the fuel tank comes to mind.
Are you sure the thruhulls are just simple plastic? Usually marelon valves are mated to marelon thruhulls. Simple plastic is rarely used below waterline.
Mark
I have some Marelon mushroom type thru hulls in white for over 40 years. Marelon will say it on them if they weren't sanded off.
Wow! I'm glad to hear they've held up so long!
I have all ball valves on a new to me boat that's been sitting on the hard for the past couple of years. They definitely need to be lubed and exercised. Seeing how much the nipple of the mushroom bends makes me a bit nervous. Not everyone will think to support the valve while opening/closing it -- especially in an emergency! I'll look into upgrades but In the meantime, I think a bushing or washer around the mushroom nipple would help support the valve and lessen the chance of a breakage
Why not just replace any OEM "valve on a thruhull" with a stronger seacock valve? Forespar and (more recently) TruDesign make strong composite valves that meet/surpass ABYC recommendations.
As for Marelon color, we have had firings in both white and black, produced over the decades by the originator, RC Marine, and later by ForeSpar.
Also... while no one asked... any thruhull fitting that is 30 to 40 years old really does not owe you a thing. Just retire it/them and bow and thank them for their faithful service/obedience to your safety and enjoyment.
As for Marelon color, we have had firings in both white and black, produced over the decades by the originator, RC Marine, and later by ForeSpar.
Also... while no one asked... any thruhull fitting that is 30 to 40 years old really does not owe you a thing. Just retire it/them and bow and thank them for their faithful service/obedience to your safety and enjoyment.
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+1Why not just replace any OEM "valve on a thruhull" with a stronger seacock valve. Forespar and (more recently) TruDesign make strong composite valves that meet/surpass ABYC recommendations.
As for Marelon color, we have had firings in both white and black, produced over the decades by the originator, RC Marine, and later by ForeSpar.
Also... while no one asked... any thruhull fitting that is 30 to 40 years old really does not owe you a thing. Just retire it/them and bow and thank them for their faithful service/obedience to your safety and enjoyment.
dj
The white plastic thru-hulls that came on the Mk2's is Marelon. The thru-hulls were and still are white and the ball valve and seacocks are black. The color does not matter. The problem is not the thru-hull, it is how the loading from the fittings are transferred to it. With the ball valve, the thru-hull is loaded in bending with no supporting flange. On the flanged seacock, the load on the thru-hull is nearly pure tension with the flange supporting the compression to result in the resistance to bending. That makes the stress on the thru-hull only a fraction of what it is with the ball valve.
One challenge that you will have is how to deal with the deep recess in the hull. Catalina used the Marelon 250 thru hulls which have a very large head that is set into a recess to make the thru hull flush. The new flush thru hull will not fill the recess. I used the standard headed thru hull and then covered over the recess with G-flex epoxy to make it flush.
I should also note that 3 out of 4 of mine had leaks between the thru hull and seacock when sealed using the recommended Teflon tape. The buttress threads have a lot more space between the parts than you have in the NPT straight threads. I removed the seacocks and put paste pipe dope and then covered that with a couple of turns of Teflon tape and none have leaked since.
I should also note that 3 out of 4 of mine had leaks between the thru hull and seacock when sealed using the recommended Teflon tape. The buttress threads have a lot more space between the parts than you have in the NPT straight threads. I removed the seacocks and put paste pipe dope and then covered that with a couple of turns of Teflon tape and none have leaked since.
I've never had one seal properly with teflon tape. Even using specialty 1/8" thick teflon tape. I've had them leak with pipe dope too. In both applications, they seal well initially, but mysteriously and suddenly begin leaking after a year or two. I just seal them with sealant now and never have a leak.
Mark
There's like a bunch through hulls on this boat so it's a project to replace them. The one I pulled was made by RC. I looked them up and discovered that Forespar had bought them in the 80's. I'm wondering why I have an RC branded valve on a 94 Catalina.Why not just replace any OEM "valve on a thruhull" with a stronger seacock valve? Forespar and (more recently) TruDesign make strong composite valves that meet/surpass ABYC recommendations.
As for Marelon color, we have had firings in both white and black, produced over the decades by the originator, RC Marine, and later by ForeSpar.
Also... while no one asked... any thruhull fitting that is 30 to 40 years old really does not owe you a thing. Just retire it/them and bow and thank them for their faithful service/obedience to your safety and enjoyment.
Seems to me like a much bigger project cleaning up a boat full of water than changing any number of thru hulls. Another note - these polymer based through hulls have a life span that is not indefinite. 20 years is a good long time. The degradation mechanisms of polymers are very difficult to impossible detect without destructive testing - which defeats the purpose anyway. But hey, it's your boat....
dj
And here’s one with the old triangle flange. Nowhere near as strong as the 93 series..
Ancient history at this point, but I believe that ForeSpar bought up the RC Marine line in the very early 90's. My late 80's boat was all black RC Marine valves and thru hulls. All changed out for the ForeSpar "93 series" design seacock system.