Marelon Sea Cocks / Valves

[Tranona]

I agree all you say except the last paragraph
Hanse say they fit DZR yet I & others have had some failures
It has to be accepted that Hanse are telling the truth
One further has to consider outside influences. Ie what electrical currents are being generated by surrounding influences. My unit is not connected electrically to anything

Sorry to disagree, but despite what Hanse might say, doubt DZR would disintegrate in the way you described. Brass have been commonly fitted to many modern boats, which is what has prompted the issue. DZR has been in use for 30 years and more and does not have a history of failing in that way.

Replace them with items you know are DZR or bronze.

 

[PeterR]

I agree all you say except the last paragraph
Hanse say they fit DZR yet I & others have had some failures
It has to be accepted that Hanse are telling the truth
One further has to consider outside influences. Ie what electrical currents are being generated by surrounding influences. My unit is not connected electrically to anything

Why does it have to be accepted Hanse are telling the truth?. Hanse only claim they use fittings from the DZR family. Dufour make the same claim for their boats. The Hanse forum appears to give test results showing fittings that are not much different from domestic brass. The same can be said for Dufour.

I have not seen any adverse comments from those who have fitted genuine certified DZR fittings as opposed to some "DZR family facsimile"

 

[Scarron]

This thread amply illustrates the case for Marelon - if it's made of black plastic it can't corrode..

Whereas if its a metal and a brassy/bronzy brown colour you will have cause to doubt either yourself, your chandler or some bloke on the Internet who said it'll be fine.

What's the worst that can happen?

Er it might just drop off without warning and your boat sink!

 

[Sans Bateau]

Scarron, that is simply not true, I understand Marelon also has its problems, thats what stopped me using it. If you buy real bronze or real DZR from a reputed source it will have the correct markings on it and then there is no doubt.

 

[KellysEye]

>black plastic it can't corrode

Marelon is a proprietary formulation of polymer composite compounds using composite polymer resins and additives.

>Scarron, that is simply not true, I understand Marelon also has its problems

Please can you expand on that, since Merlon doesn't corrode and the handles don't break off, which can happen with metal throughulls.

 

[JerryHawkins]

They are incredibly strong

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.

Not used them, but will when I replace mine. Looking at the PDF for the valves on their web site, they show a 155Kg weight hanging off one connected to their skin fitting!

 

[JerryHawkins]

Valve sizes

Hi Jerry
I had a look at the Truedesign website. The product looks good but I dont like the flow restrictions in the valves - the 1/2", 3/4" and 1" all have the same aperture of 19mm and the 1 1/4" and 1 1/2" valves have a 32mm aperture. I could be gettting rid of the corrosion problems but getting blockages.
Do you concur?
Martin

Yes, I see what you mean. Could be an issue depending on your application. I suppose you could use the next size up valve and corresponding skin fitting then use a reducer after the valve to suit your hose size.

 

[cagey]

Fireproof and melting

When I had my boat coded 7ish years ago surveyor wanted some seacocks and flanges replaced, asked about Marelon and he dismissed the idea as he thought they were a weak alternative if there was a fire, melting etc I presume. Have absolutely no idea if he was correct but it seemed plausible. Apologies if I am dissing a good product.
Keith

 

[prv]

he dismissed the idea as he thought they were a weak alternative if there was a fire, melting etc I presume. Have absolutely no idea if he was correct but it seemed plausible.

Marelon fittings are not fireproof. Then again, neither is your GRP hull.

Pete

 

[Talbot]

Marelon fittings are not fireproof. Then again, neither is your GRP hull.

Pete

It is a fairly aggressive way of putting out the fire!


IMHO worrying about the effects of fire on the skin fitting at the bottom of the bilge is not understanding the risk involved.

Heat rises, most fires are very likely to be seated well above the bilge, thus any fire that has melted the throughhull has already melted the rubber/plastic hoses higher up and thus allowed water into the compartment (which will probably stop the valve from melting anyway!!)

But if it has got hot enough to melt this composite, then the boat will be lost anyway.


A much higher risk is associated with running aground where the marelon thruhull is unlikely to be as resistant to damage as a bronze one. However, the backing plate system for a proper marelon install should minimise the effect of that damage.

It is a risk I am prepared to take. All my thruhulls will be repaced with Forespar marelon this winter.

 

[prv]

But if it has got hot enough to melt this composite, then the boat will be lost anyway.

That was more or less my point. It's not a risk worth worrying about, except possibly in steel boats.

Pete

 

[vyv_cox]

I agree all you say except the last paragraph
Hanse say they fit DZR yet I & others have had some failures
It has to be accepted that Hanse are telling the truth
One further has to consider outside influences. Ie what electrical currents are being generated by surrounding influences. My unit is not connected electrically to anything

Only just come to this thread, so have not commented previously. I have read through the thread on the Hanse Owners Assoc. site. It is pretty clear that the valves fitted are brass, not DZR. I have yet to see a chromium plated DZR valve and the photos I can see, which do not include yours, all show plating. As far as I know all DZR valves will have the CR logo cast into them.

It has already been mentioned that Dufour said their valves were DZR, but then they backed down and admitted that they were in fact brass. So I would not necessarily believe Hanse. When it comes to the skin fittings and hose tails I would be very surprised if they were DZR and the examples on the Hanse site are clearly brass.

If you can tell me what information is cast into your valve body I will comment further. A photo here would be nice.

 

[Plevier]

Does the problem of brass skin fittings include the cooling water inlet grille? Do they make those in ordinary brass as well or is that likely to be OK? I know my other fittings are brass because at least one - heads outlet, the big one of course! - is turning pink. (2003 Jeanneau)
Suspect Vyv may be best placed to answer this but interested in other experience too.

 

[vyv_cox]

I would expect the common type to be brass, simply because they are stamped from sheet metal. Bronze is mostly cast and only seen in special applications as sheet. 70/30 brass sheet is widely available. It may be rather less susceptible to dezincification as it is alpha phase only but I am not certain about that.

 

[Sans Bateau]

>black plastic it can't corrode

Marelon is a proprietary formulation of polymer composite compounds using composite polymer resins and additives.

>Scarron, that is simply not true, I understand Marelon also has its problems

Please can you expand on that, since Merlon doesn't corrode and the handles don't break off, which can happen with metal throughulls.

Nothing about corrosion, here are some bits, try Google yourself if you want more:

http://www.cruisersforum.com/forums/f115/marelon-seacock-replacement-71984.html

Some mixed views here, but still a common theme, they seize and the handles DO break. According to one post they need to be greased twice a year.

http://www.cruisersforum.com/forums/f55/marelon-seacock-maintenance-lube-32569.html

This is what put me off. Ive never heard of a Bronze/DZR/Brass (even ) handle breaking off. And if they need lubing twice a year that is just more faf than necessary. IMO DZR will do the job, is robust, is well priced and with the ball running in a nylon (?) seat will be far more forgiving.

 

[Plevier]

I would expect the common type to be brass, simply because they are stamped from sheet metal. Bronze is mostly cast and only seen in special applications as sheet. 70/30 brass sheet is widely available. It may be rather less susceptible to dezincification as it is alpha phase only but I am not certain about that.

Another thing to change then!

 

[garethmking]

Marelon Valves

My 30 year old aluminium hull sloop is fitted with six ball action marelon valves. I have never had any problem in the 30 years, just turn them off and on several times each season to remove any crustacea growth which could damage the rubber seal.