The Evolution of the Sea Cock

Continuing with the theme I began in yesterday's post lets take a look at sea cocks and valves today. The photo below, again taken at the Mystic Classic Boat rendezvous over the past week end show one of the original sea cock valves used "back in the ...

30th July 2010.
By Ed Sherman

Continuing with the theme I began in yesterday’s post lets take a look at sea cocks and valves today. The photo below, again taken at the Mystic Classic Boat rendezvous over the past week end show one of the original sea cock valves used “back in the day”.

Actually I see three gate valves in the photo above. This is a good example of the ABYC learning the hard way over time and adjusting what gets said within a standard as we learn about some of the real world problems that exist. In this case, as you look at the valves can you determine if they are opened or closed? I certainly can’t, and that’s the rub, and lesson learned. The valves could be opened, closed or somewhere in between, effectively restricting water flow, perhaps to an unacceptable level for the system being supplied with sea water. The valve on the far right side of the photo is the main sea cock supplying cooling water to the engine on this boat. If it’s not opened all the way, the engine could suffer from water starvation and overheat, perhaps causing serious damage.

Also, assuming an emergency situation with water gushing into the boat and now it’s time to close the valve. How many turns (and how much time) will it take to stop the flow of inrushing water?

So, in the photo below you see a different type of valve, in this case several “ball” valves.

The valves above happen to be installed in a boat’s fuel system to control switching of fuel delivery from one fuel tank to another. What’s more important here and really the lesson learned, is that the valves function in a 90 degree sweep from fully closed (as shown) to fully open (the handles in line with the piping). Categorically this is the preferred valve type today, and recommended in several ABYC Standards. Whether in a fuel system, or sea water valve, by using this type of valve you can instantly tell whether the valve is opened or closed and when you need to close it in an emergency, it just takes a quick flip of the valve handle to accomplish the task.

So, check your own boat and see what valve types you have installed. Replacement could be a very worthwhile project over the winter if you find gate valves in use.


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Ed Sherman

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Ed Sherman is a regular contributor to boats.com, as well as to Professional Boatbuilder and Cruising World, where he previously was electronics editor. He also is the curriculum director for the American Boat and Yacht Council. Previously, Ed was chairman of the Marine Technology Department at the New England Institute of Technology. Ed’s blog posts appear courtesy of his website, EdsBoatTips.
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