Marelon fittings?

[osprey877]

I need to replace the 3/4' seacock and related plumbing in my forward head. The seacock needs to accept three separate lines: sink drain, toilet supply, and deckwash pump. Only one is likely to be in use at any one time so there is no problem with overloading the seacock. The current setup is bronze and includes a bronze cross fitting that accepts four tailpieces, one of which is connected to the seacock. I would like to switch to a marelon seacock, but the only marelon fittings seem to be a straight or elbow hose barb.
Are there marelon tees/y connectors, 40 degree elbows etc. etc. like there are in bronze, or can I use pvc or nylon fittings? If not, can I attach bronze fittings directly to the marelon seack, or do I need to insert a piece of hose or similar??

Thanks again for all the help.

[Kenomac]

On our boat I use Marilon directly to bronze through hulls. Be sure to use plenty of teflon tale and don't overtighten.

[leftbrainstuff]

Whats the problem with bronze?

I'd avoid brittle pvc or weak nylon fittings on any below the waterline circuits.

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[Kenomac]

Originally Posted by leftbrainstuff

Whats the problem with bronze?

I'd avoid brittle pvc or weak nylon fittings on any below the waterline circuits.

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Marelon is not PVC or and won't corrode like some types of bronze. Especially important to consider on some waste fittings which sometimes contain a very caustic slurry.

[HopCar]

I'd stick with bronze, especially if you're going to put a manifold on it. Bronze is stronger and if you use American made seacocks and thu-hull fittings, you'll get high quality bronze that will outlast the boat. You may want to take the opportunity to replace that 3/4" thru-hull with a larger one in case you actually do use two functions at the same time.

[Kenomac]

Not all bronze is created equal, and these days it takes a metallurgist and manufacturer data to sort out the mess. Marelon takes away the guesswork and eliminates the possibilty of corrosion.

I've only found two reliable manufacturing sources for Naval bronze, one in Italy and the other in Florida. I spoke directly to the plant metallurgist prior to installing bronze on my boat.

Most think bronze is stronger until you've had a bronze fitting break apart in your hands.

[capngeo]

Originally Posted by osprey877

The seacock needs to accept three separate lines: sink drain, toilet supply, and deckwash pump.

Two supplies and a drain combined at the through hull? IMHO, through hulls should only be one way streets

[Snowpetrel]

I am with Kenomac on this, those marelon fittings are tough, just fitted an new forespar seacock to my alloy boat, cutting the skin fitting to length was hard work, had a go bashing the piece I had cut off. Very strong..

Trudesign also make some pretty nice reinforced plastic pipe fittings.

Another option is to have a floating, or remote manifold, this removes the load of several hoses hanging from the seacock.

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[Sailmonkey]

Originally Posted by capngeo

Two supplies and a drain combined at the through hull? IMHO, through hulls should only be one way streets

No worries, ours is the same, and has never been a problem. The head inlet, wash down pump inlet, and vanity sink drain are all in one. This setup also allows easy flushing of fresh water through the head for time away (no stinky dead critter surprise!)


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[sck5]

I had marelon on my first boat (Caliber 33) and found that they were virtually indestructible but the handles were not. If you get them be sure to exercise them monthly or they are apt to freeze up. When they broke (two of them did) it was because the handle broke off the stem. I replaced with marelon again and found religion about exercising them regularly and never had a problem after that.

[crabcake]

Originally Posted by osprey877

I need to replace the 3/4' seacock and related plumbing in my forward head. The seacock needs to accept three separate lines: sink drain, toilet supply, and deckwash pump. Only one is likely to be in use at any one time so there is no problem with overloading the seacock. The current setup is bronze and includes a bronze cross fitting that accepts four tailpieces, one of which is connected to the seacock. I would like to switch to a marelon seacock, but the only marelon fittings seem to be a straight or elbow hose barb.
Are there marelon tees/y connectors, 40 degree elbows etc. etc. like there are in bronze, or can I use pvc or nylon fittings? If not, can I attach bronze fittings directly to the marelon seack, or do I need to insert a piece of hose or similar??

Thanks again for all the help.

From what I have read (could have been on a CF thread) there are two grades of Marelon - one OEM, the other 'consumer' grade. The OEM is supposed to be much stronger. That said,the following are YouTube videos are very telling.

https://www.youtube.com/watch?v=l5ajZ3nfzzQ

https://www.youtube.com/watch?v=-tzB3IiImpo

https://www.youtube.com/watch?v=yTbuCZ1Xd1s

(there are more)

And, here is a Groco test

https://www.youtube.com/watch?v=KKTKQUcvU9w

[Kenomac]

The above tests are somewhat missleading in the way they've been used to make a point on this thread. In the first video, it was a white PVC through hull that failed, not the marelon valve. Also, the tester did not compare, nor was it the point of his video to do so, a 5-10 year old DZR bronze (brass) through hull fitting that's been exposed to seawater to a black marelon through hull fitting. I assure you, that he'd be able to break off the DZR bronze (brass) fitting probably just by bumping into it accidentally while setting up the test.

We've had a handle break off a marelon 1/2 fitting over the summer, but that was when a guest dropped a 100lb mainsail on top of it, the through hull or valve didn't break off, just the handle that seemed sacrificial. But to make a proper comparison, we've had an entire 1 1/2 inch DZR bronze through fitting completely break off while just attempting to open a stuck handle.

[Maine Sail]

Originally Posted by Kenomac

In the first video, it was a white PVC through hull that failed, not the marelon valve.

Incorrect that thru-hull fitting was genuine RC Marine / Forespar Marelon. If you view the video at about 48 seconds you will see that the thru-hull fitting is embossed with RC Marine which is Marelon.

Originally Posted by Kenomac

Also, the tester did not compare, nor was it the point of his video to do so, a 5-10 year old DZR bronze (brass) through hull fitting that's been exposed to seawater to a black marelon through hull fitting. I assure you, that he'd be able to break off the DZR bronze (brass) fitting probably just by bumping into it accidentally while setting up the test.

In the US we do not use substandard DZR brass we use a proper 85-5-5-5 bronze.

Originally Posted by Kenomac

We've had a handle break off a marelon 1/2 fitting over the summer, but that was when a guest dropped a 100lb mainsail on top of it, the through hull or valve didn't break off, just the handle that seemed sacrificial. But to make a proper comparison, we've had an entire 1 1/2 inch DZR bronze through fitting completely break off while just attempting to open a stuck handle.

I would not wish a DZR brass thru-hull or valve on my worst enemies boat. DZR brass is only slightly better than Home Depot grade yellow brass. The fact that any builder will go so far to cut corners, on such an important item, is a complete travesty.

If you want Marelon you'd want to use the Forespar 93/OEM series products. Do be careful however as the ID of the 93 series is smaller than comparable bronze (in order to get the strength required the thru-hull wall had to be made much thicker) so you'll usually need to up-size the seacock..

[osprey877]

Thanks all for advice on the Marelon v. Bronze issue. However, what I need is advice on how to connect three 3/4' hoses to a Marelon seacoc (or a bronze seacock if I can find the bronze fittings I need. I think need a bronze or marelon pipe cross or a Tee) and a short nipple to connect the cross to the seacock. I cannot find any tees or cross or pipe nipples in anything other than brass or galvanized black pipe. Does anybody know any source for these in bronze (or Marelon or similar)? If I can't find in bronze or Marelon, am I better off using nylon or brass? If I cant find a bronze pipe nipple, am I better off using a short length of hose, or a brass pipe nipple?

[Sailmonkey]

Originally Posted by osprey877

Thanks all for advice on the Marelon v. Bronze issue. However, what I need is advice on how to connect three 3/4' hoses to a Marelon seacoc (or a bronze seacock if I can find the bronze fittings I need. I think need a bronze or marelon pipe cross or a Tee) and a short nipple to connect the cross to the seacock. I cannot find any tees or cross or pipe nipples in anything other than brass or galvanized black pipe. Does anybody know any source for these in bronze (or Marelon or similar)? If I can't find in bronze or Marelon, am I better off using nylon or brass? If I cant find a bronze pipe nipple, am I better off using a short length of hose, or a brass pipe nipple?

You can't find a bronze "t" or nipple?!?! Where are you?


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