"PLASTIC" SEA VALVES

[MIKE_MCKIE]

\"PLASTIC\" SEA VALVES

I read some time ago of plastic sea valves, I think in PBO. I currently have the WC inlet & discharge & 2 Cockpit drain valves that are all somewhat the worse for wear & would like to consider replacing with plastic instead of bronze. Also are there similar skin fittings, for use under the w/l? (not the wimpy little nylon ones for above the w/l)
Anyone know where I can get them/view/look up on web?
All advice gratefully received.
Cheers
Mike

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[ChrisE]

Re: \"PLASTIC\" SEA VALVES

I've a feeling that when these have been talked about before the consensus was these are a big no-no on the grounds that a fire on board could melt them and sink the boat. Might be wrong but I'd check carefully if I were you.

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[npf1]

Re: \"PLASTIC\" SEA VALVES

The Marelon seacocks from Forespar appear to be robust so should not snap easily if something falls against them or the hose. Don't know about the fire situation though.

<hr width=100% size=1>Have boat. Will travel. Maybe cruising in 2005 - wanna join me?

 

[MIKE_MCKIE]

Re: \"PLASTIC\" SEA VALVES

That's the one, Marelon. Thanks very much for jogging the memory cell. The article was by one of the PBO contributors & was included in the build of his new boat. Since I believe he is a naval architect/yacht designer, I guess he knows what he is doing.
Thanks again, I will have a browse around to find stockists etc.
Cheers
Mike

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[dickh]

Re: \"PLASTIC\" SEA VALVES

I think ASAP Supplies do them - but check the prices, they may work out more expensive than traditonal skin fittings & ball valves. Plastic would be ideal for a steel or aluminium boat though.

<hr width=100% size=1>dickh
I'd rather be sailing... /forums/images/icons/smile.gif

 

[MIKE_MCKIE]

Re: \"PLASTIC\" SEA VALVES

Thanks for pointer, I was going in circles! Price for 1.5" sea valve is £42, a damn sight cheaper than the bronze w/c valves currently fitted, and no fears about electrolysis either.
Plastic for me at the next dry dock!
Thanks to everyone for your help.
Cheers
Mike

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[maxi]

Re: \"PLASTIC\" SEA VALVES

www.aquafax.co.uk

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[Wiggo]

Re: \"PLASTIC\" SEA VALVES

and how bad a fire would it have to be to melt the fittings below the waterline, Chris? The flexible plastic pipes connected to good old-fashioned bronze seacocks wouldn't melt, of course.

<hr width=100% size=1>Nihil curo de ista tua stulta superstitione.

 

[ChrisE]

Re: \"PLASTIC\" SEA VALVES

I'm the world's no 1 technoclutz, so I've no idea. I was just relaying the memory of a previous post. You could of course turn the bronze cocks off, so a fire on an unattended boat would sink it, it might be burnt out but it wouldn't sink!

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[jfm]

Re: \"PLASTIC\" SEA VALVES

Actually most boats have fire proof (perhaps inverted commas around "proof") hose for the engine cooling water inlet pipes, and some boats (all MCA coded should) have fireproof hose for all the other seacock hoses. So I think Chris is right, plastic seacocks would represent an incremental fire/sinking risk.

Perhaps a bit academic beucase if there's any decent fire I'm in the liferaft anyway. Would rahter it burnt out beyond repair and sank, dont want a half-burned still-floating boat. But I suspect plastic seacocks kills any chance of MCA coding (if you care about that)

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[Oldhand]

Re: \"PLASTIC\" SEA VALVES

Had Marelon seacocks on our last boat and they gave no problems whatsoever for over 10 years.

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[LittleShip]

Re: \"PLASTIC\" SEA VALVES

Mike
just one point that has not been mentioned, plastic through hulls should not be fitted on wooden hulls ?????

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I wish I'd been born rich instead of good looking ?

 

[PaulJ]

Re: \"PLASTIC\" SEA VALVES

I have been fitting out my steel hull for the last seven years and leaking seacocks caused a large proportion of the delays which meant I couldn't launch this year. Having tried three different types of plastic seacock and looked at a couple of others, this is something I have pretty good knowledge of!

The plans specified "Patay" seacocks so at great expense I ordered a total of seven of them..... I need five plus one spare of each size. Patay are excellent seacocks and very robust but the problem arose when I tried to get hosetails for them. Those supplied by Patay are simply inadequate, made of thin comparatively flimsy plastic and only long enough to put one jubilee clip on. I found a couple of other different hosetails but I simply couldn't seal the threads. I tested them by attaching a hose, closing the seacock and filling the hose to a head of 2mtrs. I tried sealing them with PTFE and also a solvent free goop and in all but one case the water seeped up the threads. Reluctantly I decided that if I couldn't find decent plastic hosetails for the Patay cocks I would have to find some different seacocks.

Thus it was that I came to try the Forespar marelon seacocks. This time I only bought four (once bitten, twice shy!) and I tested them in the same way but this time before installing them. This time ONE of them actually held the water overnight. The other three all leaked and this time the hosetails were fine, it was the seacocks themselves that leaked. One of them leaked so badly that you could actually blow through it when it was in the closed position! I was pretty cross about this so I rang Forespar in the States and the guy I spoke to said.... and I quote.... "Yes they do leak sometimes, it's the way they're moulded". I was not impressed. After much discussion Mr. Forespar said that it sounded as though I needed their super duper 93 range and he gave me the website address:-

http://www.forespar.com/catalog/plumbing/integrated.htm

These are in fact a very nice product and come with an integral hosetail. Although they do make a nominal 1 1/4" size, unfortunately the thread is not 1 1/4" BSP (but some other thread profile) however they could do me some with a BSP thread
as a "special order". More expense and another delay but I was desperate so that is what I went for. They are quite compact but seem very robust and do not leak. So far I am very pleased with them.

As for the "theoretical" problem of them melting in a fire, frankly I think that if a fire gets so bad that it gets that hot that low down I fear the boat is lost anyway but just to make me feel better I have protected them with some of that silver foil backed noise insulation foam which is also fire resistant.

I hope this helps and if you can find some decent hosetails I have some very nice Patay seacocks (1 1/4"BSP) going cheap! ;o)

<hr width=100% size=1>I used to have an open mind but my brains kept falling out.....

 

[Mudplugger]

Re: \"PLASTIC\" SEA VALVES

Mike, In process of fitting out steel bath tub under surveyor's supervision, told in no uncertain terms that plastic seacocks below the waterline are not acceptable! so had to go for s/s! ( Vetus) at a price but thread wise they are compatible with std hosetails. HTH Tony W.

<hr width=100% size=1>Tony W.

 

[Ships_Cat]

Re: \"PLASTIC\" SEA VALVES

Just use industrial glass reinforced plastic ball valves and fittings (including hosetails). They don't leak and cannot afford to leak (like no one wants corrosive liquids leaking out of valves in industrial situations).

John

<hr width=100% size=1>I am the cat but I am only 6.

 

[jimboaw]

Re: \"PLASTIC\" SEA VALVES

Marelon valves on my boat which was launched in 91 are just fine. No leaks. No sticking.no problems at all. Would demand them if I could ever afford to get a new boat built!

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[pwc51]

Re: \"PLASTIC\" SEA VALVES

Having replaced the ball valves twice in short order we decided, about 8 years ago to put the marelon ones on our boat. They have been great and never given us any problem - no de-chroming, no de-zincing etc. They are still as solid as when we fitted them

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[PaulJ]

Re: \"PLASTIC\" SEA VALVES

Thanks John. In fact I did find one industrial one that might have been ok but they didn't have the sizes I needed in stock. Had I not "stumbled" upon the Forespar 93 range I might have followed that one up. There was also another "industrial" type that I found, made of shiny grey plastic with a red handle.... They were fearsomely expensive, about £80 each I think. I never tried them but I thought they looked pretty good. However the guy in Aquafax (who is a friend of mine) told me that they had had several brought back with problems.... I can't remember precisely what problems. Anyway, I am sorted now..... I hope!

Paul.

<hr width=100% size=1>I used to have an open mind but my brains kept falling out.....

 

[simonfraser]

Re: \"PLASTIC\" SEA VALVES

plastic on a wooden hull is just what the pbo designer chap did, in the last few issues

Simon

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[Graham_Wright]

Re: \"PLASTIC\" SEA VALVES

Try your local industrial pipeline suppliers and push for a big discount.

Ours (Watkins and Powis in Gloucester) do beautifully engineered ones in 316 stainless.

Depends on the size of course but not as expensive as you might expect.

<hr width=100% size=1>GBW