Skin Fittings

Playtime

Playtime

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I have to replace 2 skin fittings (cockpit drains from a centre cockpit) that are permanently underwater. The current fittings are stainless but one is badly pitted outside and both are badly rusted inside (in the engine compartment). So much for being 'stainless' - they must be the 'wrong' stainless!

So, what is the 'right' stainless for this application or should they be bronze - any old bronze or 'special' bronze?

Finally, what is the best material to bed the new fittings - epoxy? sikaflex? something else?
 
The best is proper bronze, worst brass (including tonval (i think that's what it's called) which is sometimes sold as bronze, but is little better than ordinary brass. Mild steel's another good way to lose your boat, but you're unlikely to find that!

DZR brass is OK. I'm not sure I'd want stainless for that job, but A4 or 316 (the same thing) should be OK. A2 isn't - that's for non-critical above the waterline use.

I'd use a marine sealant - not an adhesive. You, or a subsequent owner may want to change them, and epoxy means taking an angle grinder to them. Adhesive sealants aren't quite as bad, but are likely to involve a lot of swearing come replacement time
 
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OK - where can I get 2" plastic ones to which I can then attach a seacock?

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PLASTIC CAN BREAK=BOAT SINKS!
actualy ok above water line...
 
Personal experience but we had a plastic skin fitting, one of many, suddenly fail and were lucky to be rescued as the flow of water through a 2" hole was more than the bilge pump could cope with.

Others on board didn't fail nor did the "original" bronze fittings of 20+ years of age.

Bed in a good sealant, not an adhesive, as you'll find most good sealants are very secure.
 
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The best is proper bronze

[/ QUOTE ] That is right bronze should be first choice.
DZR brass is the second choice

Avoid ordinary brass as that will dezincify and also Tonval. Although it is a leaded brass it is not dezincification resistant even though it is sometimes sold as such.

Failure of a Tonval fitting was the major factor in the near loss of the FV Random Harvest of Brighton several years ago. Dig out the MAIB report and read.
 
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Personal experience but we had a plastic skin fitting, one of many, suddenly fail and were lucky to be rescued as the flow of water through a 2" hole was more than the bilge pump could cope with.

Others on board didn't fail nor did the "original" bronze fittings of 20+ years of age.

Bed in a good sealant, not an adhesive, as you'll find most good sealants are very secure.

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You couldnt' find a way to stop the flow through a 50mm skin fitting? No wooden plugs aboard, seat cushions, even an old jacket. a jam jar, a dinghy oar. ......... Someones shoe clad foot over the hole?
 
This plastic skin fitting was infact the NASA speed log fitted by previous owner in the engine bay virtually out of sight and VERY inaccessible. It had failed between the flange nut and the hull and the wooden peg driven into the original hole knocked the remaining part of the fitting out making an even larger hole.

I was solo motor sailing at the time and was unaware of the failure initially and when it was discovered there was already 18" deep water below decks. The Spanish emergency services were excellent, two launches rafted either side of us and they used a 100mm submersible pump to get the water level down while taking us back to port where the lift out crane and TV were waiting for us.

This was the only time in several years in the Med area that I was asked for Insurance papers and my I.C.C.
 
Oh do beware of plastic fittings just think about it metal seacock plastic skin fitting -think of the stress/vibration that is possible and which one will fail - go for bronze
 
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