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Brass Sea Cocks


I recently went to one of the IIMS working group and training sessions. These are for surveyors to discuss any new or ongoing problems they find and to keep us up to date with developments.

The lecture in the afternoon was about mechanical systems. This started with a look at sea cocks. We were all shocked when the lecturer read out the RCD ( Recreational Craft Directive ) guidance regarding sea cocks.

The directive basically states that a seacock is a hole in the hull which must have a means of closing and last for five years. YES FIVE YEARS!!!

What this means is that it has become acceptable to fit brass rather than bronze through hull fittings and valves. So of course some of the manufacturers of yachts and motor boats are doing just that. Fitting brass saves them up to 80% of the cost of a bronze fitting. Do not think that this is restricted to less expensive yachts and motor boats, some of the really expensive vessels have been found with these fitted.

It is well known that brass will dezinkify when submerged in salt water and leave a very weak copper fitting. But it will probably last for five years so is acceptable under European rules.


Sounds pretty stupid to me.


The discussion around this by a room full of surveyors took so long that other mechanical items were only briefly covered and will wait for another time. I think all the surveyors present were amazed and went away thinking that on many fairly new boats the sea cocks will need particular cleaning of paint etc. to look for any signs of dezincification.

There is more coming about various forms of sea cock including stainless steel, bronze and plastic.