For preventive maintenance reasons, I am planning to replace my somewhat corroded galley drain through hull components (at least the pipe and valve). The current arrangement is through hull→connector–>pipe–>valve. I plan to replace it with the same design in bronze, as given the leverage of the long pipe, I would worry about the strength of plastic components under lateral loads. Have you done a similar replacement, if so what did you use? Can you recommend a good source for the connector(above the through hull), or the threaded pipe?
No need for the pipe. You can use Marelon or nylon and hose after the valve.w
Hi Mike,
What Paul said… probably best to use a Marelon valve attached directly to the thru-hull fitting. Here is a photo of my head sink drain setup on 30U so give you an idea. I don’t think a solid copper pipe is appropriate either. With hull flexing eventually the solid components are going to break something somewhere. Whereas hose flexes, also note the hose is attached with two stainless steel hose clamps. And the hose should be a type rated for below the water line installation… don’t buy it from Home Depot. Also note the wooden bung attached to the hose in case it is needed to plug the thru-hull in an emergency.
Don
’87 NS30U #369 – Breezin’
Vabcouver, BC
Definitely a marelon valve and then hose. This is a permanent solution. Bronze fittings are very old school. Just check the clamps every year. Double clamps above the waterline are not necessary but the extra weight won’t hurt!
Ron, Don, and Paul, thanks for the answers/advice and picture. I expect I will go with a flanged marelon valve on the existing bronze through hull , perhaps with a beefed up backing plate if the through hull threaded tube is long enough. And then some modifications to the access hatch on the floor of the galley sink cupboard to ease access to that space.
Mike
Yes… Marelon. Not nylon- it will not meet ABYC standards and has other drawbacks. There’s a practical sailor article that just came out reviewing the current options: Marelon Through-Hulls: Why They're Worth Reconsidering - Practical Sailor
Dan Weinstein , Look Farther, 30C #205, East Greenwich RI
I believe that Marelon is a trade name for the composite material used by Forespar. Tru Design is a New Zealand company that makes a similar product. Check them both out if you are not going with bronze. Make sure that whatever you use that your set up allows for full movement of the handle. Also if you go with composite remember they should be exercised at least once a month. Forespar sells a lubricant for their shut offs. If not used regularly the ball can stick and too much force can break the shaft.
A few years ago Scott P. Installed Tru Design through hulls on Timaru/Salish Morning, a 30C. He did a nice including making backers with G10 board.
Mark Powers
Thanks Mark and Dan. I will review that info.
Mike
Based on a quick review of the manufacturers’ websites and their local distributors, I have the impression that Canadians are better off with TruDesign (purchasable at Pumps & Plumbing – Victory Products ), while U.S. buyers may want to stick with Marelon.
You can get TruDesign in the U.S. from Marine Plumbing Components & Hardware | Boat Plumbing Parts & Fittings .
However, on a quick skim-through, it looks like the Forespar Marelon components purchased at Marelon Plumbing Overview might be cheaper for U.S. purchasers.
– Bob
I have replaced all my through-hulls and valves with Tru-Design. They have a very impressive range of products.