Seacock & thruhull replacement

[CHM]

I just replaced all of mine in a 1988 Beneteau having had one fall apart while replacing the galley sink. That was enough for me as I had thru hulls which looked ok and others which were likely original to the boat. Many were inaccessible behind cabinets and I had to dismantle the heads in order to access these tires fittings. Some of them may have been ok, but after seeing one disintegrate accompanied by a lot of water flooding the bilge, I replaced them all with flanged Groco bronze fittings. It wasn’t cheap, but I won’t have to worry about them for a long time now.

[mkinney716]

Any recommendations for which ones to use on a steel hull ? Mine are marlon and I cannot close a couple of them. I’m going into yard in a couple of months and will change them all out.

[bcboomer]

Originally Posted by mkinney716

Any recommendations for which ones to use on a steel hull ? Mine are marlon and I cannot close a couple of them. I’m going into yard in a couple of months and will change them all out.

Trudesign.

I replaced a Marelon one for the same reason and replaced the old bronze ones because the survey said they were compromized and could fail unexpectedly.

More than 6 years and they are absolutely trouble free.

[DeValency]

Originally Posted by bcboomer

Trudesign.

I replaced a Marelon one for the same reason and replaced the old bronze ones because the survey said they were compromized and could fail unexpectedly.

More than 6 years and they are absolutely trouble free.

+1 for Trudesign. Made a serious survey before replacing 11 of my old bronze seacocks last year. One thing is that you should check well on your throughhull threads unless these are replaced as well (as I did).

[GetAway2]

Valve in picture #1 looks good, just needs a little cleaning up. Valve in picture #2, not sure what it's for but I'd replace it, it looks really bad (IMHO).

The outer through hulls look good from the picture, just clean them/it up. If they are 5 years old pull all of them and replace them.

It's your life is it worth a bad valve? Carry a GOOD assortment of wooden plugs!! Also I would add a second strap to each valve.

[Manateeman]

A professional job. Really nice work. A thru hull with a ball valve is not a seacock. Plastic junk just saves OEM builders time and money.
A supported ball valve is not connected to the hull. Measure the thickness between the bottom of the threads and the interior of the thru hull.
That’s it. It doesn’t matter if you epoxy the thru hull in. It’s a thru hull not a seacock. Plastic...cheap...sell more boats.
Again, nice to see nice work.
Happy trails to you.
Mark and his manatee friends.

[Manateeman]

My post was for the work photographed by Captain SENGLAND.
Mark

[Blakhomer]

This is my aft head. It would seem I have three thruhulls below the waterline with the sink drain one looking particularly corroded. Fair to say I should replace this one soon?

[Coginchaug]

If you go with Groco, they have outstanding customer service including personalized instructions and hints on installation issues. When I repaced some seacocks and thru-hulls, they provided invaluable advice. Send them an email and they are very responsive.

[Manateeman]

Hi. It looks like thru hulls with ball valves stuck on top. There is a marine how to web page which will help. Maybe someone here can give you the exact page.
The sink need not be below the waterline...can be at the boot but then you would have to fill up the hole. Next boat maybe.
Groco #1
Read some of my posts on seacocks vs supported valve .
Just don’t use Marelon.
Happy trails to you.
Mark and the manatees ( not dugongs)

[DeValency]

Originally Posted by Blakhomer

This is my aft head. It would seem I have three thruhulls below the waterline with the sink drain one looking particularly corroded. Fair to say I should replace this one soon?

Definitely! And I would do all the three already at this time.
If the skin fittings are still in a really good shape replace the seacock only with bronze. If you replace the skin fittings, I’d recommend TruDesign (composite) complete set for each.

[MikkiDuda]

Originally Posted by mkinney716

Any recommendations for which ones to use on a steel hull ? Mine are marlon and I cannot close a couple of them. I’m going into yard in a couple of months and will change them all out.

I have some 10 cm lengths of threaded steel pipe welded to the hull as through-hull. Then brass or bronze valves screwed on the pipe. You get a couple of years from brass and much more from bronze. Easy to change the valves during slipping. The through-hulls have been like that for the 40-45 years since the boat was build.

I was chatting with an older guy in the club who build his own boat and said he added a second larger diameter pipe around the first one as protection. A bit overkill as I do not think a 1-1.5" pipe welded both inside and outside the hull would break that easily.

[Heathenly Twins]

Originally Posted by Manateeman

I would not put a Marelon valve in any boat. I’m removing all of mine. Neither would I ever install the New supported valves because the valve is not bolted down. I don’t consider them seacocks manatee

Sorry to slightly derail this thread but why do you dislike Marelon seacocks? I need to replace all of my bronze seacocks due to de-zincification and was thinking Marelon would be best to avoid corrosion. I had them on a previous boat and they seemed ok. Worked fine. No sword of Damocles feeling.

[DeValency]

Originally Posted by Heathenly Twins

Sorry to slightly derail this thread but why do you dislike Marelon seacocks? I need to replace all of my bronze seacocks due to de-zincification and was thinking Marelon would be best to avoid corrosion. I had them on a previous boat and they seemed ok. Worked fine. No sword of Damocles feeling.

Can appreciate opinions on bronze bolted seacocks. Personally, I don’t like to bolt anything unnecessary to my hull. Yes, one can add a glassed backing plate and bolt to it, but my hull is already min 50mm thick and this will be problematic with most skin fittings.
Anyway, a year ago I made a small survey with multiple sources, owners and pros before replacing 11 skin fittings and seacocks. As a result, decided to go with TruDesign composite systems. I’ve seen few complaints on Marelon and decided not to use this brand. I’m very happy with my TruDesign, so far...

[Blakhomer]

Thanks for the advice gents. I will schedule the haulout for next month and I think I will replace all the thruhulls, seacocks and skin fittings at the same time. I don’t know when the previous owner did them and this will give me more piece of mind. I would prefer to go with bronze even though it’s more expensive and I have read some good things about composite. Size wise, is there much variety in the market? I gather each one on my boat would have some marking that will allow me to replace like with like. I’d like to order them ASAP rather than wait for haul out.