SS seacocks and piping to engine?

vas

vas

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discussing with a friend (plumber by profession and part time diver for archaeological underwater excavations by the ministry of culture here...) about the various crafts I've been checking lately and I did mention the bronze (or whatever that colour thing is) seacocks, that looked rather sorry and hard/burnt rubber piping leading to the engines that seems to be the norm.
He was thinking that using SS seacocks with their respective ss anchilaries leading to ss hard piping to the engine and finishing off with a small piece of rubber tubing elbow would be much better, safer and needing less maintenance overal.
I was worried about electrolysis, but not too knowledgeable on that front, so asking here for opinions (or pointers to threads that has been discussed)
I'm aware of the tread dealing with the various types of bronze casts and their performance, but I don't recall any mention of ss.
Finally, is there any reason that silicon tubing isn't used (or so it seems on the ones I've checked) as it should last much longer.

cheers
 
I see no-one has responded as yet, so when I was looking into brass and bronze skin fittings, I found vyv cox at www.coxengineering.co.uk was very knowledgable and helpful in this specialist area of metals, seawater and electricity. You can also PM him. Might also be worth reposting your qusetion on the practical boatwners forum.
 
There is no need for stainless, although some people use it. The biggest drawback is crevice corrosion, particularly in threads. The alternative is composite, which are popular on steel hulls where bronze/DZR has to be isolated, but they are bulky and no real advantage in a wood or GRP boat. Rigid piping is not suitable as most engines are flexibly mounted. The correct grade piping is reliable and durable.

The only question with yellow metal seacocks is to ensure they are DZR. I have just removed a DZR engine water intake after 18 years and it is still in pefect condition - as was the flexible pipe.
 
thanks for the replies, sorry for the late reply was away for a short break.

DZR or not I remember an old thread on here that was clarifying all this, will go back to it once I manage to secure a boat.
My main concern/question/puzzle if you wish was that all the crafts I've seen have been out of sea for at least 2-3 years some even more and all had dunno 2.something inch rubber tubing from seacocks to engine that were looking OK, but not "feeling" OK: What I mean is that trying to squeeze them felt like they were cracking and falling apart. From other industrial applications, this in my book is polymerised/burnt out or whatever you want to call them but defiinitely not fit for purpose!

Hence my origina question.
I do understand that the engines are on rubber mounts, and that's why I was asking for SS up to the engine and a small elbow to join it to the engine.
Is silicon piping (lined I assume) good for sea water?

cheers

V.
 
virtuvas said:
thanks for the replies, sorry for the late reply was away for a short break.

DZR or not I remember an old thread on here that was clarifying all this, will go back to it once I manage to secure a boat.
My main concern/question/puzzle if you wish was that all the crafts I've seen have been out of sea for at least 2-3 years some even more and all had dunno 2.something inch rubber tubing from seacocks to engine that were looking OK, but not "feeling" OK: What I mean is that trying to squeeze them felt like they were cracking and falling apart. From other industrial applications, this in my book is polymerised/burnt out or whatever you want to call them but defiinitely not fit for purpose!

Hence my origina question.
I do understand that the engines are on rubber mounts, and that's why I was asking for SS up to the engine and a small elbow to join it to the engine.
Is silicon piping (lined I assume) good for sea water?

cheers

V.
Click to expand...

Flexible hoses to the right specification really are not a problem. Suggest you look at the Vetus catalogue which shows two types, one rubber and one silicone www.vetus.com
 
SS seacocks and pipeing to the engine

If the pipes and welding is tig welded with 316 extra, low carbon there should never be a problem with the joints ,should last the life of the boat.:D
 
Bronze or DZR is better than Stainless 316 for underwater corrosion.

Mixed metals are bad.

Bonding is good.

Stainless is bad for crevice corrosion.
 
SS and pipework to the engine

Stainless 316 elc is not a mixed metal so it will not corrode under cavation,if tig welded with the correct filler ie 316 elc it will last the life time of the boat using pure argon gas or helium as a shielding gas when welding .:D
 
Bandit said:
Bronze or DZR is better than Stainless 316 for underwater corrosion.

Mixed metals are bad.

.
Click to expand...

Strange statement; Surely bronze (and brass) are mixed metals, albeit at as microscopic scale, both being alloys. I'd imagine a 24 carat silver/ gold alloy would be OK as far as corrosion was concerned, but a bit expensive and weak !
 
Agreed Bandit, there was also mention of attaching a rubber or silicone hose to the stainless which will cut off any oxygen supply making the stainless steel rust almost as quickly as steel wont it.

As to stainless steel pipes, what marina fitter in their right mind would try to bend them round a tight engine space, ?

The heat expansion will crack all the joints in no time at all.

I know stainless steel is used in food industry where heat expansion is an issue but from what I have seen they use a concertina pipe to get around the expansion issues, that would mean a 2 inch rubber boat pipe would have to be a 3 inch stainless steel pipe making it even less attractive.
 
SS and pipework to the engine

Daka all due respect ,stainless 316 elc comes in diameters and angles 45 degrees ect,can i ask if you are in engineering or a marine fitter,no disrespect meant.:)
 
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