Seacocks... MARELON or BRONZE

[CarlF]

There are two forespar Marlon valve lines. The only Marlon one you want to consider for a seacock is the "OEM Series 93" valves. These are a completely different from the regular kind - much stronger and the handles don't break. I've had them for six years and they are as reliable and as easy to turn as when installed. Despite the "OEM" label, you can buy these for an existing boat.

Two notes with these:

The plastic thru-hull is thick so you may need to order one size up to get the same water flow. I would use 1" valves instead of 3/4" for extra strength.

You should use the companion Forespar thru-hull that is designed for the "buttress" thread on these valves.

[Tim R.]

The bronze seacocks are also stronger.

Here is some more info that may be useful to determine which is best for your boat.

Lubrication for Marelon Ball Valve - SailboatOwners.com

BTW, Forspar makes something called Marelube. Guess what it is for.

[CarlF]

New bronze is stronger than Marlon but corroded bronze is much weaker than Marlon. I've seen corroded bronze valves simply fall off in my hand. And unfortunately, bronze today is a bit of a crap shoot. It's not the same stuff as in the old Spartan valves.

My previous boat had the other kind of Forespar valve. They required greasing or they got stiff. Some of them got stiff even with greasing.

I have not experienced this stiffening with the Series 93 valves and don't bother to grease them. I do exercise them twice a year. They continue to be so smooth that I don't see how grease would make a difference.

Has anyone had Series 93 valves get stiff so that you felt the grease was needed?

[laika]

Originally Posted by CarlF

New bronze is stronger than Marlon but corroded bronze is much weaker than Marlon. I've seen corroded bronze valves simply fall off in my hand. And unfortunately, bronze today is a bit of a crap shoot. It's not the same stuff as in the old Spartan valves.

There still is some high quality bronze hardware out there, Spartan included. You just have to pay for it.

[Suijin]

Bronze below the waterline, Marelon above if you're willing to replace them as they break. Just replaced one for the propane drain on my boat and I doubt it was five years old. The exterior flange blew off when the boat was power washed when last hauled. O.O

[zboss]

When I replaced my thru hulls this summer I went with bronze. The PO had a few marelon thru hulls. She had struck an obstruction of some sort and it sheared off the mushroom cap on the outside. Although the boat did not sink, when I went to replace it, the thru hull popped off as easily as pulling a tab off a new milk carton.

Its my understanding that the ball gaskets inside the groco bronze thru hulls are marelon and its recommended to use the forespar marelon grease on them.

[boatpoker]

Real bronze corrosion is extremely rare, I've actually never seen it. Groco had a recall years ago when their Chinese suppliers switched to brass without notice and those did corrode.

European builders, Hanse, Bavaria, Jeanneau, Dufour, Beneteau and their offspring Lagoon have been using chrome plated brass ball valves with tapered threads on straight thread through hulls for years and these do suffer from galvanic corrosion.

I always apply a side load with my foot on throughulls and valves when surveying, gently at first then building as far as I dare. I do not do this with Marelon as all but the biggest ones (1 1/2" - 2") bend enough to scare me.

I'll stick with real bronze.

[Watercolor]

Autumns Wind - Earlier this year there was a similar discussion about Forespar's Marelon and bronze seacocks.

http://www.cruisersforum.com/forums/...re-103175.html

You might find this an informative read if you're really interested in finding out about Marelon thru-hulls and seacocks.

Simple facts:

1. A significant portion of cruisers who say they never have had a problem with their seacocks, really do have a problem and never know it. Until it'd too late or they're just lucky.

2. The Forespar 93 series Marelon valves weakest point is the handle. In particular, the nylon nut that the handle bolt screws into.

3. Marelon is nothing more than Dupont Zytel nylon. Nylon is hydroscopic and will lose around 60% of its strength in water. In about 3 months the threads on the nut will become soft and have little strength.

4. The Catalina Owners Association has issued a warning about this issue. The design of the 93's internals are a serious failure point. If the nut and handle pull out of the housing, which has happened a lot ball can't be closed.

5. The OD of the 93 thru-hull is oversized so you would have to significantly enlarge the hull hole.

6. The 93 1/2" and 3/4" seacocks use the same thru-hull. The same holds true for the 1" and 1 1/4" and the 1 1/2" and 2". If you need a 3/4" flow rate capacity you need to install a 1" unit, a 1 1/4" capacity requires a 1 1/2" unit and if you ned a 2" capacity flow rate you're out of luck.

7. If you find you don't like the Forespar 93's and want to get rid of them, you'll need to glass in all the ports because the Forespar 93 thru-hulls sizes have a non-standard oversized OD.

Fair winds