Q&A: Can I Use Bronze Sea Cocks In An Aluminum Boat?

Question: Do you have bronze sea cocks in your aluminum hull and if so what level of corrosive activity have you seen?

Answer: We have bronze sea cocks insulated from the hull with fiber spacers. The through hulls are plastic. There is no sign of any corrosion around most of the sea cocks, which are located in the engine room. The only exception are the head sea cocks located forward. Here the hull plate under them is showing some light pitting from copper salts dripping off the sea cocks over the last 20 years. I think the reason that the engine room sea cocks don’t have this problem is that the heat from the engine and generator keep them and the surrounding area pretty dry, whereas up forward the area is often wet from condensation, particularly when we are in cold water areas (most of the time).

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Meet the Author

John

John was born and brought up in Bermuda and started sailing as a child, racing locally and offshore before turning to cruising. He has sailed over 100,000 miles, most of it on his McCurdy & Rhodes 56, Morgan's Cloud, including eight ocean races to Bermuda, culminating in winning his class twice in the Newport Bermuda Race. He has skippered a series of voyages in the North Atlantic, the majority of which have been to the high latitudes. John has been helping others go voyaging by sharing his experience for twenty years, first in yachting magazines and, for the last 12 years, as co-editor/publisher of AAC.

2 comments… add one
  • Patrick Piret Oct 28, 2012, 8:18 am

    Dear John ,

    We are building a new 50 ft sailyacht based on a Dijkstra plan but finishing in another yard as their usual builders . I have one question to you ;
    Fuel tanks are incorporated in the hull and coated to prevent MIC corrosion . The fuel lines are of copper pipe which we insulated in plastic pipe and the valves are brass insulated with the white thread teflon tape .
    Is this also what you have on your boat and is this common practice ? What is the alternative for copper and brass fittings for this ?

    • John Oct 28, 2012, 10:03 am

      Hi Patrick,

      I really don’t like the sound of all that copper and brass and I doubt that the Teflon tape will provide adequate isolation.

      We use aluminum tank fittings which you can source from from an aircraft supply house. We also use rubber fuel hose, attached with hose clamps over barbs, not copper tube.

      If I were doing it again, I would use the same aluminum fuel tank fittings but look into one of the many patented fuel line systems that use pressed on end fittings, like those used for hydraulic hose.

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