Seacocks - Bronz or Plastic

[osirissail]

Originally Posted by MV-Romnya

. . .- 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

By "plastic" I hope you mean "Marelon" by Forespar.

If so then fine, - but - be sure that the newly assigned seacock is mounted on the hull far enough below the waterline that you won't be sucking air into it when the boat is heeled or in choppy waves.

[Zzzeke]

Originally Posted by 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

I would be careful about connecting a 1" heat exchanger supply line to a 3/4" water source, if that's what you are contemplating.

[osirissail]

+1 on Zzzeke - - AND - do not connect a 3/4" hose to a 1" heat exchanger!!!!

It is not so much that the engine may or may not run hot due to insufficient water volume flow - It is that the reduced water volume flow will most probably not be sufficient to cool the "rubber" exhaust hose. And then the rubber exhaust hose will overheat and "cook/burn" a hole sometime now or later. Then you will have a world of troubles.

[MV-Romnya]

Thanks osirissail and Zzzeke good advice so I take it the whole circuit shoud be the same ie 1 inch - or the intake seacock must be larger that the water carring tubes to the heat exchange ? MVR

[osirissail]

Yes. If the inlet size of the first item in the raw water circuit - e.g., the raw water pump is 1" then the minimum size of the hose/tube and strainer needs to be 1" or greater.

[MV-Romnya]

Thanks osirissai - I got the picture - k