Are Gate Valves OK for Seacocks?
Gate valves can't provide a quick visual reference on whether a through-hull is open or shut. And the handles tend to rust.
August 23, 2014
Question: I’m considering the purchase of a 60-year-old wooden powerboat that I’ve fallen in love with. I do have a question though. In the photo I sent in you can see the handle for the seacock used for the engine raw-water intake.
Gate valves like the one shown on this raw-water intake are still fairly common on old boats, but marine surveyors don't look kindly on them -- for good reason.
It is a bronze gate valve that the current owner says was in the boat when he bought it some 15 years ago. I’ve read that these are not compliant with current industry standards. Is that true and if so why?
Answer: This question does come up from time to time, as we still see a fair number of boats using this type of valve as a seacock. Plain and simple, they are not compliant with current ABYC Standard H-27. The standard dictates a handle with a 90-degree throw from fully open to fully the fully closed position. The reason for this is pretty simple; it gives the user a quick visual reference in the event of an emergency as to whether the valve is open or closed. It’s pretty hard to make that determination with a gate valve. Beyond that, most gate valves will introduce material shortcomings like mild steel handles that will eventually rust out, and/or the use of brass that may not actually fare too well in the saltwater environment. Probably any marine surveyor these days would call this out as a part of a pre-purchase survey -- so if you do go ahead and decide to buy, it could become a negotiating point as part of the sale.
