Abandoning Seacocks/Through Hulls

[UrsusMaritimus]

We are redoing our waste system which currently has y valves at each head, that allow direct discharge overboard. In the course of the refit, we will be removing these valves and so the associated seacock will be no longer in use. Short of a haul out and removal/fiberglassing the holes, what’s the correct way to “abandon” a seacock?

 

[Comodave]

I would put a short section of hose on it and cap the hose. Then make sure the seacock stays closed. Prefer to remove it and glass it closed but short of a haul out not much else to do that I can think of. Unless you can get the barb fitting out of the seacock and put a plug into it directly.

 

[UrsusMaritimus]

Thanks Commodave, that’s what I was thinking too. We may reuse some of them, but, once we’re sure, we’ll glass the others up at our next haul out. We’ve also switched to fresh water only flush, so we have 4 seacocks to eliminate.

 

[Comodave]

Look for bronze plugs and make sure they aren’t brass. A lot of places sell brass and call it bronze. Check out reputable marine retailers.

 

[SeaDogAK]

When I bought my boat, I had a couple of abandoned seacocks glassed over. Easy peasy.

 

[BDofMSP]

I would put a short section of hose on it and cap the hose. Then make sure the seacock stays closed. Prefer to remove it and glass it closed but short of a haul out not much else to do that I can think of. Unless you can get the barb fitting out of the seacock and put a plug into it directly.

That's what I did. I don't need and can't use a macerator in the Great Lakes but I left the seacock in case plans change. I wired the valve closed and exercise it once a year.

 

[HopCar]

If they’re modern seacocks they have a female pipe thread where the tailpiece screws in. Just remove the tailpiece and screw in a bronze pipe plug. No need for any hose. Put the seacock in the closed position and remove the handle.

 

[CharlieO.]

Mine are capped with fittings as Parks^^ mentions.

 

[Bacchus]

For anyone located any where winter freezing is a problem be sure to drain the ball cavity when plugging. Seacocks should have a drain plug for that purpose.

 

[jleonard]

I removed 4 from the Albin I had and glassed the holes. Not only did I eliminate a potential future problem, I gained some valuable storage space under the head cabinets.

 

[jgwinks]

My last two boats had the head discharges abandoned but the seacocks left in place. The first had the black Marelon seacock and the PO just removed the tailpiece and replaced with a matching Marelon plug. The valve never got exercised so it was stuck closed. I never got around to glassing over the hole. The current boat has the old Wilcox Crittenden bronze seacocks with the built in tailpiece. The abandonned one has a short piece of hose with a plug in it and of course the valve left closed. I'm currently working on eliminating some of the 25 (!) through hulls and that is one that will go away.

 

[RT Firefly]

Greetings,
At one point during our ownership of our 46' Cheoy Lee I had a couple of redundant sea cocks replaced with Marelon thru-hulls with a matching/mating cap. No danger of corrosion nor necessity of grounding.

 

[tiltrider1]

As Comodave stated, I would cap my seacock. At the next haul out I removed and glassed over the abandoned seacock.

 

[Comodave]

On our last boat I removed 3 old transducers and a sinistered bronze ground plate. So I had 7 holes to glass in. I got pretty good at it.

 

[Shrew]

Here is what I did.

My seacock was threaded on. On top was an NPT thread to hose barb. I got an NPT thread to NPT Thread. I removed the NPT to hose barb, installed the NPT to NPT, then installed a bronze female threaded cap. I couldn't find the correct size male threaded plug, so I had to (Above) instead.

The hose idea has a few problems. It will eventually rot. I don't want to have to inspect what is a non-functioning seacock and replace the hose. Hoses are tricky to block well.

 

[fgarriso]

Groco has Stainless Steel thru-hulls with external and internal threads that you may be able to get a plug that fits the threads. That would allow you to quickly change out the fitting with a plugged one.

 

[Comodave]

I don’t like S/S under the water in a critical application. Much prefer bronze, no crevice corrosion issues.

 

[fgarriso]

I agree but couldn't find a bronze in Graco with internal threads.

 

[UrsusMaritimus]

Thanks for all the great feedback, I can’t cap them off, so will use a hose and plug, and will remove them and glass them over at the next haul out.

 

[Steve DAntonio]

I strongly recommend against glassing over unused/removed seacocks, a sound but abandoned seacock is far more reliable than a secondary FRP bond (doing this properly requires a considerable scarf ratio, which is often not achieved). Inspect the seacock, make sure there are no signs of corrosion, pack it with grease, cap/plug it.

More in the attached and here https://stevedmarineconsulting.com/fiberglass-repair-and-secondary-repairs-steering-you-straight/

 

[Comodave]

I strongly recommend against glassing over unused/removed seacocks, a sound but abandoned seacock is far more reliable than a secondary FRP bond (doing this properly requires a considerable scarf ratio, which is often not achieved). Inspect the seacock, make sure there are no signs of corrosion, pack it with grease, cap/plug it.

More in the attached and here https://stevedmarineconsulting.com/fiberglass-repair-and-secondary-repairs-steering-you-straight/

Steve,

We did a 12:1 ratio and used epoxy on our last boat and didn’t have any issues, at least before we sold the boat. I removed about 7 through hulls and old transducers. The new owner hasn’t reported any issues to me and they have used the boat extensively. If done with the correct ratio and epoxy have you seen problems?

 

[psneeld]

I repaired 2 holes the size of basketballs in the bottom of a Shamrock 26 in assistance tow duty. Used epoxy and cloth.

A severe duty boat and still going strong after 15 years or so.

The holes were formed due to delamination from way oversized props too near the hull and constantly picking up rope in the prop plus some metal flex conduit and rebar whacking the bottom for hours.

The boat was/is continuously run aground too

The repairs are still holding despite similar severe duty....can't imagine a trawler seeing that kind of service where typical thru hull are placed.... maybe way up forward and pounding through seas might test the repair.

But I can see the greasing and capping as an alternative, probably much safer for those that don't have a lot of experience in glass repairs.

 

[rpackard]

You or the next owner of the boat might have plans to go further a field where pump out stations do not exist. The Great Lakes is not the only boating area that contains trawlers. By glassing over the through hull fittings ,You are limiting the number of future buyers.

 

[J.T kearney]

Steve D
Your method of cleaning, filling with grease and capping is a great Idea and also the easiest. Just have to make sure the thru hull is still well bonded to the boats bonding grid!!!
Cheers and Merry christmas all
J.T.

 

[Circumnavigator]

I strongly recommend against glassing over unused/removed seacocks, a sound but abandoned seacock is far more reliable than a secondary FRP bond (doing this properly requires a considerable scarf ratio, which is often not achieved). Inspect the seacock, make sure there are no signs of corrosion, pack it with grease, cap/plug it.

More in the attached and here https://stevedmarineconsulting.com/fiberglass-repair-and-secondary-repairs-steering-you-straight/

That's certainly true, but it is possible to remove seacocks safely. I put circles of fiberglass inside and out, drilled to match the bolts that held the seacock in place, with loaded West resin in the hole. Both inside and outside should be sanded to bare glass. Lots of loaded West resin on all surfaces and silicon bronze bolts, nuts, and washers. Overcoat the bolt heads on the outside.


As for plugging the seacock, McMaster does not list any bronze pipe plugs. They have them in 28 other materials, including titanium ($100 for a 1" NPT plug), which suggests strongly to me that no one makes them in bronze. If I were doing this, I probably would choose nylon or ABS, as any of the metals would be a question in a bronze seacock.


And, as noted above, if you haul the boat for the winter, make certain you remove the plug and open the ball valve, so there is no water left in the fitting.


Jim

 

[HopCar]

“As for plugging the seacock, McMaster does not list any bronze pipe plugs. They have them in 28 other materials, including titanium ($100 for a 1" NPT plug), which suggests strongly to me that no one makes them in bronze. If I were doing this, I probably would choose nylon or ABS, as any of the metals would be a question in a bronze seacock.”

If you look at marine suppliers you’ll find bronze pipe fittings. They are not silicon bronze but a high copper tin with very little zinc. They work fine in salt water. I’ve heard the term Red Brass or Red Leaded Brass used to describe them.
https://www.jmesales.com/smith-cooper-bronze-1-1-4-in-square-head-solid-plug-fitting-threaded/

 

[Pcpete]

When I converted to fresh water flush I capped one of the incoming through hulls and connected the other one to a new raw water wash down system. There was only one discharge fitting so I ran a replacement hose that connects to the top of the tank as an additional vent.

 

[Sailor of Fortune]

If I was considering keeping the boat for a few years, I'd glass over the old removed seacocks... Not sure why this seems to be risky...Routine F/G work that is well proven....

 

[jgwinks]

I strongly recommend against glassing over unused/removed seacocks, a sound but abandoned seacock is far more reliable than a secondary FRP bond (doing this properly requires a considerable scarf ratio, which is often not achieved). Inspect the seacock, make sure there are no signs of corrosion, pack it with grease, cap/plug it.

More in the attached and here https://stevedmarineconsulting.com/fiberglass-repair-and-secondary-repairs-steering-you-straight/

My boat has 18 through hulls at the water line, no seacocks on any of them. Apparently they weren't required in 1973, they are now. And they're all white plastic with UV degradation so they had to go. Several are tucked in behind the exhaust pipes with only a couple inches clearance so no room to add a seacock. Those are the ones I'm removing and I have no choice but to glass them over with all the work being done from the outside. I'm replacing the through hulls and adding proper seacocks to all that have room. The plastic through hulls actually made the project easier, a couple whacks with a hammer and chisel and they shattered. Hardest part was picking up all the tiny pieces.

 

[jgwinks]

To cut the bevels for glassing over the holes I took a regular heavy duty 7" 36 grit sanding disc and cut a wedge shaped piece out of one side. Then stuck it back together with fiberglass and epoxy on the inside to form a cone and extra layers of glass at the center. Drilled a hole in the center for a bolt to chuck in my electric drill. It cuts a perfectly round 12:1 bevel in about 30 seconds. Well worth the half hour it took to make it.