Marelon Sea Cocks / Valves

[Blue5]

I am in the early stages of researching options for when I need to replace the seacocks on our boat, Marelon being one of the considerations.

The set up we have involves a through hull onto a 30/45* bend and then the valve but looking at the Forespar site they only appear to do 90* bends

I am sure others must have come across this problem and would also welcome an experience/ tips on fitting these.

I also see from the Forespar tips/instructions that they require a backing plate on all through hulls but given the close proximity of the cluster on our boat I am not sure if this is possible or why it would be required.

 

[charles_reed]

Glass-reinforced polyamide of the nylon family.
Comparable to bronze in strength and ideal for aluminium hull through fittings.
What's wrong with bronze? (Not brass which is definitely not for through-hull fittings)

 

[Tranona]

Marelon valves are more bulky than metal ones, so you may find there is not enough space to fit them.

On a GRP boat they have little advantage over DZR in terms of corrosion resistance and are more expensive. Clearly have advantages in metal boats.

 

[Blue5]

Glass-reinforced polyamide of the nylon family.
Comparable to bronze in strength and ideal for aluminium hull through fittings.
What's wrong with bronze? (Not brass which is definitely not for through-hull fittings)

Nothing wrong with bronze, as the thread said, researching options, so looking for peeps personal experience of fitting and living with the "plastic" alternatives.

 

[prv]

Marelon valves are more bulky than metal ones, so you may find there is not enough space to fit them.

Looking at the OP's picture, I think you may be right. Definitely close enough to warrant careful checking of dimensions before buying any.

Pete

 

[Blue5]

On a GRP boat they have little advantage over DZR in terms of corrosion resistance .

From the info I was reading that was a big plus point "corrosion resistant and free from electrolysis", care to elaborate.

 

[prv]

From the info I was reading that was a big plus point "corrosion resistant and free from electrolysis", care to elaborate.

Bronze or DZR seacocks in a GRP hull don't usually corrode or electrolyse either. Mine are 20 years old and good as new, many are twice that. So while it's certainly true that marelon is free from corrosion, it's a bit of a red herring because so are the conventional choices.

As Tranona says, the situation is different on metal hulls, where bronze seacocks need to be mounted using insulating gaskets and sleeves and similar palaver, and a plastic valve that sidesteps the whole problem is a welcome innovation.

Pete

 

[Blue5]

Bronze or DZR seacocks in a GRP hull don't usually corrode or electrolyse either. Mine are 20 years old and good as new, many are twice that. So while it's certainly true that marelon is free from corrosion, it's a bit of a red herring because so are the conventional choices.

As Tranona says, the situation is different on metal hulls, where bronze seacocks need to be mounted using insulating gaskets and sleeves and similar palaver, and a plastic valve that sidesteps the whole problem is a welcome innovation.

Pete

OK, thanks, I was viewing it the negative sense but that explains it.

 

[Sans Bateau]

When I was researching sea cocks prior to my change over (to DZR) I looked at Marelon and found some less than favorable reports on some U.S forums. If I remember correctly, there were cases of the valve sticking, then the handle breaking off.

DZR valves and fittings were so easy to obtain from A.S.A.P at a reasonable price it became no contest.

 

[JerryHawkins]

Tru Design valves

Have a look at Tru Design valves and fittings. They don't appear to be much more bulky than the DZR alternatives and seem extremely robust. http://www.leesan.com stock them in various sizes. Have a look at their web site, http://www.trudesignplastics.com/products/45-ball_valves.

 

[Blue5]

Have a look at Tru Design valves and fittings. They don't appear to be much more bulky than the DZR alternatives and seem extremely robust. http://www.leesan.com stock them in various sizes. Have a look at their web site, http://www.trudesignplastics.com/products/45-ball_valves.

They look interesting, have you used them?

With all these various makes it is nice to see a bit of history about them, don't want to be the guinea pig.

 

[Blue5]

When I was researching sea cocks prior to my change over (to DZR) I looked at Marelon and found some less than favorable reports on some U.S forums. If I remember correctly, there were cases of the valve sticking, then the handle breaking off.

DZR valves and fittings were so easy to obtain from A.S.A.P at a reasonable price it became no contest.

Thanks for that info, hadn't heard about those problems will do a bit of Googling.

I am aware of some boatbuilders only giving valves a 5 year life and want to be sure any replacement doesn't have this caveat attached, I have also seen reports of some builders claiming to use DZR but metallurgy tests suggesting otherwise.

 

[Scarboroughsloop]

I'm also thinking about the Marelon seacocks. My understanding was that the issues were usually down to misuse by the user. Not opening/closing the fitting for a long time and then using too much force when trying to open them. Also I think mainly on the older style.

 

[AndrewB]

The two Marelon seacocks (on my cockpit drains) are the only ones aboard to have lasted the life of the boat (30 years).

They are very slightly larger than corresponding sized bronze seacocks. The most obvious drawback they have is that they will not resist heat in the event of a fire, so should not be used in the engine-room.

 

[KellysEye]

We had Marelon through hulls on our steel boat. Looking at the the spacing of your throughulls in your picture the slightly larger size won't be a problem ours were closer than that. We also had them in the engine room. If you are worried about fire fit a gas heat triggered extiguisher system.

>The set up we have involves a through hull onto a 30/45* bend and then the valve but looking at the Forespar site they only appear to do 90* bends

Your picture look as though the throughulls are straight so I'm not sure where the bend comes in.

 

[Talbot]

The set up we have involves a through hull onto a 30/45* bend and then the valve but looking at the Forespar site they only appear to do 90* bends

I would suspect that the standard Marelon through hulls are not right for your application, however, if you look further on the site, the Flowtech vlaves would appear to be ideal

flotech-performance-valve

 

[prv]

>The set up we have involves a through hull onto a 30/45* bend and then the valve but looking at the Forespar site they only appear to do 90* bends

Your picture look as though the throughulls are straight so I'm not sure where the bend comes in.

?

Quite clear to me, in the pictures. A 45 degree bend between the hull and the valve, then the hose comes straight off the valve.

Pete

 

[capetown]

About eight years ago we fitted a 3/4" marelon valve to the under water sink waste.

After about three years use, it tighten up, so now we use a tube over the handle to increase the leverage. I know it should be dismantled to find out what's wrong.

It's the only marelon valve I've had in all my boats and the only one to play up.

 

[Scarboroughsloop]

Are you able to dismantle the Marelon seackocks as I didn't think you could (unless it's the old design) Also did you open/close the valve regularly or was it left for a period in one position?

 

[capetown]

Are you able to dismantle the Marelon seackocks as I didn't think you could (unless it's the old design) Also did you open/close the valve regularly or was it left for a period in one position?

I'm pretty sure it can be dismantled but would need to look.

After a sized one due to lack of use, we now exercise the valves each visit, hand crank the engine as well.