Plumbing Replacement

[walcor]

I'm starting the process of replacing the head plumbing in my 1979 Newport 27. I believe that the seacocks (plastic gate valves) are original and need replacement desperately. The boat is out of the water and I intend to replace all of the seacocks, head, engine, etc. My problem is that the inlet seacock for the head is 1/2 and the outflow seacocks are 1 1/4 inch. I've been unable to find any 1/2 inch seacocks, either bronze or marelon (bronze preferred). Also, I'm having a little difficulty in finding 1 1/4 inch sanitation hose. Any help out there? Thanks.

Wally

 

[Peggie Hall HeadMistress]

Your head intake thru-hull should be 3/4", not 1/2"...and the discharge thru-hulls should be 1.5". Both sizes are Outer Diameter--'cuz that's the Inner Diameter of the hoses that have to fit onto 'em...and all hose sizes are ID.

Those are the standard industry sizes. So I think you need to measure everything again.

 

[Ed Schenck]

Replacement thru-hulls.

You are correct Wally, there are no 1/2" seacocks. A lot of older boats used 1/2" thru-hulls. Both the engine and head inlets were 1/2" on my 1979 Hunter 37C. You can add a bronze ball-valve to the head thru-hull(easiest) or you can replace the thru-hull with a 3/4" and add a seacock(preferred).

To replace the thru-hull first glass in a 1/2" wooden plug. Then drill a small pilot hole before redrilling with a 3/4" hole saw.

If you use a ball-valve then with an elbow you can match any hose size. Picture is a before and after.

 

[walcor]

Replacement Through-hulls

Thank you for your response. I know the sizes of the seacocks because they are molded into the cases of the Bagdhad Plastics. I'm not sure of the hose that's used, so it may be problematic, and I may have to drill new through hulls, which I'd like to avoid if possible. Since plastic was used, my sense is that this was a cost-cutting measure by the company producing the boats.

The fitting that I removed is most definitely a 1/2" through-hull, and the hose going into the head is a 5/8" hose, printed right on the hose.

I appreciated your help and opinions.

Wally

 

[walcor]

Re: Replacement thru-hulls.

Thanks for the detailed information, Ed. The through-hulls are definitely the sizes that I mentioned, and there are bronze fittings for attachment of seacocks/valves. I hate the idea of drilling the hull to put in larger fittings, but I also hate the idea of doing a bad job on such an important item as a through-hull.

I'm also going to have to measure the sanitation hoses to see if the fittings were 1 1/2" on the hose side. I guess nothing is easy when working on a sailboat.

Thanks again.

Wally

 

[Peggie Hall HeadMistress]

Re: Replacement thru-hulls.

First time I've run into a boat with a 1/2" head intake....I learn something new every day.

When you replace the head, which you'll almost certainly have to do unless it's been done in the last 5 years, you can solve the problem with a short piece of 1/2" hose and a 1/2-3/4" reducing adapter.

 

[Ed Schenck]

Plumbing issues.

Two things Wally: 1) drilling a larger hole in the same place for a new thru-hull is not that difficult. And not to be feared. The main thing is expense. A 3/4" thru-hull with a good seacock is not cheap. And you want to do two.

2) keeping your 1/2" thru-hulls(assuming they are bronze) and adding good bronze ball-valves is not a bad way to go. Some feel the connection is compromised because the thru-hull is straight threaded and the ball-valves have tapered threads. But so did the gate valves that have been on there for almost thirty years. Before I did new thru-hulls and seacocks I had ball-valves. That was the first change I made in 1999, got rid of the gate valves. Even with the different threads the ball-valves went on several turns and never leaked. With elbows and adapters they can point where you want them and fit any hose size.

 

[walcor]

Re: Plumbing issues.

Hi Ed,

Thanks for that follow-up. You answered one of my main questions, the difference between a ball valve and a seacock. I'm thinking that I may try the bronze ball valve on the 1/2 inch and go with 1 1/4 inch bronze seacocks on the rest. My hose is 1 1/2 inch, so I'll go with adaptors. Most of them will be 90 degree, since that's the least bending of the hoses.

Thanks again.

Wally

 

[walcor]

Re: Plumbing issues.

Hi Ed and Peggie,

Just an interesting note. In Anchorage, I was wandering through West Marine's store there and I found a 1/2 inch Marelon seacock. Naturally, I immediately grabbed it and took it home to replace the plastic gate valve. So, I won't have to make do with a ball valve where a seacock is the appropriate way to go.

I've not seen any advertisements in catalogs for 1/2 inch seacocks, but I'm glad that I found one that will work on my boat. 1 1/4 inch seacocks are available, and I can put adaptors for 1 1/2 inch sanitation hose, so it looks like I'm on my way to replacing my plumbing. Thanks for the help and I'll let you know how it comes out. At least all of the hoses are now disconnected and the old seacocks are removed.

Wally