Seacocks - Bronz or Plastic

[MV-Romnya]

I have an old wooden boat - the bronz seacock for the raw water intake is so corroded I do not want to touch the tap to turn it off it will probally break and sink the boat - there is a good looking plastic seacock with a working tap leading to a redundant toilet - the question is can I use this plastic inlet to the engine cooling system ? - I will be changing the seacock at the next slip - I want to use the plastic one in the interim - MVR

[Billy Higgins]

I had that same problem once. If the old seacock is that bad, you should consider inserting a soft plug from the outside before you do anything else.

[skipmac]

As long as the "plastic" seacock is large engough there's no reason why you cannot use it to supply cooling water to your engine. Of course make sure that the line to the toilet is closed off so you don't suck air into the cooling line and cook your engine.

FYI that plastic is probably Marelon which is a Dupont grade of reinforced nyon.

[MV-Romnya]

Thanks for the tip Mates, I have heard of a soft plug - what sort of material is a soft plug and also when the boat is out of the water I want to seal the hole permernatley - advice please - wooden hull - MVR

[skipmac]

The old remedy plug is a piece of soft pine cut into a tapered plug. If you can do it, go over the side and drive it into the hole from the outside. The water will make it swell of course so don't drive it in too hard. Then cut it off flush.

For a wood hull boat, long term fix if you're going to eliminate the old seacock permanently I guess I would put in a new piece of planking rather than trying to patch a hole that size. But it has been years since I owned a wood boat and was never an expert so don't take my opinion on this as final word.

[Stumble]

The one thing I would say is that plastic should not be used below the waterline. They are not nearly as strong as metal ones, and have a bad habit of breaking off right where the screw post exits the side of the boat.

[Cheechako]

yes you can

[cat man do]

Originally Posted by Stumble

The one thing I would say is that plastic should not be used below the waterline. They are not nearly as strong as metal ones, and have a bad habit of breaking off right where the screw post exits the side of the boat.

Cough cough

the bronze seacock for the raw water intake is so corroded I do not want to touch the tap to turn it off it will probally break and sink the boat

Sounds like the bronze is crap as well

[Uncle Bob]

Originally Posted by MV-Romnya

I have an old wooden boat - the bronz seacock for the raw water intake is so corroded I do not want to touch the tap to turn it off it will probally break and sink the boat - there is a good looking plastic seacock with a working tap leading to a redundant toilet - the question is can I use this plastic inlet to the engine cooling system ? - I will be changing the seacock at the next slip - I want to use the plastic one in the interim - MVR

Hi short term plastic valve is good, just make sure you plug faulty bronze valve as mentioned previously. IMHO, longer term use, bronze valve below waterline.
Hull can be repaired by cutting a patch to suit hole, same timber, same thickness, and fit with a butt block behind repair. Done properly it will never be a problem.

[MV-Romnya]

Thanks All, the plastic has been in the water for some 10 Years now but not sure how long without water flowing through it - I'm guessing around 5 years - bearing in mind I only want to use the plastic seacock for the next 6 months only.

So here is the exciting part – I connect the plastic hose ¾ inch with a build up to 1 inch (has anyone done that – ¾ to 1 inch to the heat exchange) – then I try and turn off the corroded bronze tap – if it breaks I sink at the jetty – if it doesn’t I’m either lucky or a fool for touching things without it being on the slip – my aim is to be able to turn off the water at the source – I don’t trust that corroded inlet seacock

[SailFastTri]

The Forespar Marelon valves are good, but I do not recommend the Marelon mushroom thru-hulls. I installed one this Spring that cracked when it was tightened, I think because the hull on one side of the hole was a bit thicker than the other side, and it was "torqued". A bronze thru-hull would not have broken -- it might have bent to conform but not broken. My bronze thru-hulls are 11 years old and in excellent condition, no electrolysis. Do not bond them and they will hold up just fine.

[onestepcsy37]

i'm with sailfasttri, although i don't believe he's correct about a bronze thruhull 'bending' to fit an uneven surface. my bronze throughhulls are 33 years old and still in good serviceable condition. they are the old 'cone' type wilcox crittenden valves and i clean and regrease them at every haulout - usually 3 to years.

and they're not bonded - probably saved my butt when i took a direct lightning hit last year in the abacos.

[MV-Romnya]

Why do people Bond the seacock - and glad you survived the lightning strike onestepcsy37 – knowing my luck I would probably get hit twice in the same place

[David M]

Don't put anything on the engine seacock except the engine. Adding a second user of seawater increases the chances of the engine cooling system sucking air. If it doesn't first burn up your raw water impeller it might overheat your engine.

In my own experience plastic valves are horrible. The valves freeze and the handles break off. I have never had any such trouble with stainless or bronze valves.

Not everyone needs to bond the seacocks. It is not necessarily a necessity.

[MV-Romnya]

Have a look at the corroded seacock - anyone think the tap will work ?