Old Groco Rubber Cone Seacocks

[catalinajack]

I have several of these still in service, working, but stiff and difficult to open and close. I know the guts can be removed while on the hard and serviced (sanded) and lubed such that they will operate far more easily. But, here is my quesyion. Why not leave them in the open and simply hard plumb a new ball valve in line and use that as the through-hull shut-off instead? Would doing so run afoul of any ABYC recommendations. Yes, I know that new through hulls can be installed but at a significant cost. And, please, respectfully, I am not seeking responses on what anyone would do or not do. I simply want to know whether this is a viable and acceptable alternative to repair or replacement.

 

[bglad]

Don't know of a rule against adding fittings after a properly installed operable seacock. However, it might run afoul of the standard if the "assembly" cannot pass this test:

27.6.1 A seacock shall be securely mounted so that the assembly will withstand a 500 pound (227 Kg) static force applied for 30 seconds to the inboard end of the assembly, without the assembly failing to stop the ingress of water
(see Figure 1).

The 500-lb. force would be applied to the furthest inboard end of the assembly.

 

[catalinajack]

Don't know of a rule against adding fittings after a properly installed operable seacock. However, it might run afoul of the standard if the "assembly" cannot pass this test:



27.6.1 A seacock shall be securely mounted so that the assembly will withstand a 500 pound (227 Kg) static force applied for 30 seconds to the inboard end of the assembly, without the assembly failing to stop the ingress of water

(see Figure 1).



The 500-lb. force would be applied to the furthest inboard end of the assembly.

Bill, thanks for that reference. Question: the inboard end, forgive me, is that the end where the seacock passes through the hull or, in my case, through the seachest wall?

 

[Bacchus]

Here is a great resource... the balance of the site is a wealth of boating knowledge and How Tos
https://marinehowto.com/servicing-tapered-cone-seacocks/

There are several others re sea cocks that you may want to review depending on which way you go. Why not refurb those already installed unless they have more serious issues.

 

[rslifkin]

Bill, thanks for that reference. Question: the inboard end, forgive me, is that the end where the seacock passes through the hull or, in my case, through the seachest wall?

The inboard end would be where the hose attaches, the point furthest from the hull or sea chest.



Personally, if the thing is getting too hard to keep operating, I'd just replace it with a new seacock. Ultimately a better setup than a second valve added on and less points of failure.

 

[catalinajack]

Here is a great resource... the balance of the site is a wealth of boating knowledge and How Tos
https://marinehowto.com/servicing-tapered-cone-seacocks/

There are several others re sea cocks that you may want to review depending on which way you go. Why not refurb those already installed unless they have more serious issues.

With respect, as I said I am not interested in other solutions. I already know what the other solutions are. The fact is that to refurbish what I have requires that the boat go on the hard. We live on the boat. Boat goes on the hard, nowhere to live.

 

[catalinajack]

The inboard end would be where the hose attaches, the point furthest from the hull or sea chest.



Personally, if the thing is getting too hard to keep operating, I'd just replace it with a new seacock. Ultimately a better setup than a second valve added on and less points of failure.

Again, guys, all I wanted was an answer to my question. You have answered it. Thank you. I already know what I could do otherwise and said somin my original post.

 

[rslifkin]

Being that your seacocks are into a sea chest, I would expect you can come up with a way of covering / sealing the water side with the boat in the water. Small bowl with toilet ring wax over it from inside the sea chest maybe?

 

[catalinajack]

The inboard end would be where the hose attaches, the point furthest from the hull or sea chest.



Personally, if the thing is getting too hard to keep operating, I'd just replace it with a new seacock. Ultimately a better setup than a second valve added on and less points of failure.

Not fewer points of failure, just a new one. The old seacock would just stay there. It won't ever fail, can't fail cuz it would never be closed again.

 

[catalinajack]

Here is a great resource... the balance of the site is a wealth of boating knowledge and How Tos
https://marinehowto.com/servicing-tapered-cone-seacocks/

There are several others re sea cocks that you may want to review depending on which way you go. Why not refurb those already installed unless they have more serious issues.

Yes, Rod Collins' website is a great resource. Unfortunately, I have a Groco and what he shows is a different make and is not relevant to the Groco.

 

[bglad]

See attached pdf

Bill, thanks for that reference. Question: the inboard end, forgive me, is that the end where the seacock passes through the hull or, in my case, through the seachest wall?

 

[bglad]

Groco SV valves

Groco literature for those interested

 

[bglad]

Groco thru-hull adapter

If/when replacement time comes use an adapter so the valve can be replaced without replacing the thru-hull.

 

[bglad]

More from Groco

Good info. from Groco

 

[bglad]

I don't think adding a valve is the worst thing you can do to these as long as the original is still serviceable, and the metal is good. Gives you a way to operate the fitting without dealing with seepage from the rubber plug valve and still have the original to block off the hole when necessary.

 

[Comodave]

I would be concerned about adding a valve to the end due to the 500 pound 30 second test as posted above. You are giving quite a bit more leverage where it was not designed to withstand. Maybe only as a very short term fix, but the problem with short term fixes is that they tend to become long term fixes.

 

[Bacchus]

With respect, as I said I am not interested in other solutions. I already know what the other solutions are. The fact is that to refurbish what I have requires that the boat go on the hard. We live on the boat. Boat goes on the hard, nowhere to live.

Yes, Rod Collins' website is a great resource. Unfortunately, I have a Groco and what he shows is a different make and is not relevant to the Groco.

Hey my apologies for not researching completely what you have and whether RCs info applied... My bad
If not interested in other solutions by all means just add the valve on and test it with a 500 # load and see whether it is acceptable.

 

[HopCar]

One issue you’ll run into is the SV series seacocks have male straight threads on the inboard side. The ball valve you want to screw on will have tapered threads. It won’t be a strong joint. I think it’s a bad idea.

 

[catalinajack]

One issue you’ll run into is the SV series seacocks have male straight threads on the inboard side. The ball valve you want to screw on will have tapered threads. It won’t be a strong joint. I think it’s a bad idea.

Thanks HopCar, I am aware of this issue. My thought was not to thread a new valve into the existing valve directly. I was thinking a short nipple, then the new valve but, as bglad demonstrated in the illustration, the load test would be done further from the sea chest which, as another responder noted, would create more leverage. That is what I had in mind when I asked about code compliance. Perhaps it would break off with more leverage, perhaps it wouldn't. As far as testing, who here has ever dared to test their sea cocks using the 500# standard? A bit of a conundrum methinks. In any case, my several Groco SV series sea cocks still work. It just takes a bit more effort than a ball valve. The short handles don't help either. My valves still work acceptably so there is no need to replace them barring OCD incentives. I was just seeking an acceptable adaptation that would make things easier. Thanks to all for your thoughts.

 

[Comodave]

Not really sure how you could practically do the 500 pound test but I could do half a test myself…

 

[mvweebles]

CJ - question on your sea chest. I have always admired the defever design but never really looked closely. I thought one of the benefits of a sea chest is the thru hulls are accessible to clear obstruction and debris if needed. That would mean the top cover is above waterline. Thinking it through, that would make for a 4-foot tower in your engine room with no practical way to reach down to the mushroom head of the thru hull.

Can you comment on your sea chest design, benefits, attributes - beyond having a view of the bottom through the plexi lid? Pictures maybe?

As far as your valves, I'd put a length of appropriate hose between the two valves so 500 lb issue greatly reduces. Or put a 90-degree in if you can match threads. Personally, I happen to like the idea of operable valves even if configuration is odd. At least until you haul.

Peter

 

[angus99]

CJ - question on your sea chest. I have always admired the defever design but never really looked closely. I thought one of the benefits of a sea chest is the thru hulls are accessible to clear obstruction and debris if needed. That would mean the top cover is above waterline. Thinking it through, that would make for a 4-foot tower in your engine room with no practical way to reach down to the mushroom head of the thru hull.

Can you comment on your sea chest design, benefits, attributes - beyond having a view of the bottom through the plexi lid? Pictures maybe?

As far as your valves, I'd put a length of appropriate hose between the two valves so 500 lb issue greatly reduces. Or put a 90-degree in if you can match threads. Personally, I happen to like the idea of operable valves even if configuration is odd. At least until you haul.

Peter

Peter, while CJ is looking through his files, here are a couple pics of our seachest on essentially the same boat. two were taken when we replaced all 13 underwater/near waterline through hulls and seacocks, thereby helping us sleep better while enabling HopCar’s early retirement. The third was taken earlier, during survey, and is the only shot I have showing the cover in place.

The seachest isn’t quite as deep as you imagine. I have long arms and can easily reach the bottommost through hull to clear it, but that’s never been necessary. Also, it’s certainly possible to remove the 24 bolts holding the lid on to remove debris, but not fun. I’m exploring adding an access port to the Lexan cover.

As for benefits, it consolidates all of our eight underwater through hulls in one screened, well-protected enclosure: two for main engines, one generator, one A/C, one raw water washdown, one vent and two spares. (The boat used to have seawater toilets). The grill at the bottom is designed to force water into the chest while running. It is also built like a brick outhouse and structurally is part of the hull. It greatly reduces the likelihood of clogging an intake underway. I’ve read that eel grass can still be a problem, but have never experienced it. One of Arthur’s better ideas, I think.

 

[rslifkin]

Looking at those sea chest pictures, it's gotta be possible to replace a thru hull in the water. Either cover an individual thru hull from inside or block the bottom grate with something while you work.



Being that the valves still work and this isn't an emergency "fix it now", I'd take a little time to see if you can come up with a one-time fix that you won't have to go back to later.

 

[HopCar]

I suggest you loosen the T-handle, open the seacock, remove the drain plug, install a zerk fitting, and pump in some grease. Use silicone if possible so as not to damage the rubber more.

The failure mode of these seacocks is that the rubber hardens and will no longer expand or contract as you tighten or loosen the T-handle. Eventually it takes so much force to rotate it that the shaft tears loose from the rubber.

Plan to replace them next time you haul.

 

[HopCar]

Angus, thank you for making my retirement possible!��

 

[ProMaritime]

I love the old rubber bung Groco seacocks. They are bullet proof if you install them the way I did, which I would only attempt on a solid layup glass hull. On my first haulout after buying the boat in 1978 I ripped out the mixed and unmatched original seacocks and through-hulls and installed several Groco rubber bung ones.
Being new at boat ownership I was too stupid to understand why a through-hull had to be installed in a solid hull and then a seacock installed on top of that. Besides I didn’t have the money back then to buy two parts when it looked like one would do fine and they have, for the last 44 years.
After knocking out the old through-hulls I checked to ensure that their discharge holes where as large (or larger) than inside diameter of each Groco seacock. Then I drilled two bolt holes next to each discharge hole and mounted counter-sunk studs from the outside of the hull. I filled and glassed over the countersinks for a smooth and undetectable finish to the bottom.
On the inside of each hole, I laid down several layers of glass cloth to create a large diameter pad for the base of each Groco seacock. I applied slow-catalyzed resin to the layers of cloth forming the mounting pads and quickly pressed each seacock down on to the studs and into the wet glass. After the resin cured, I carefully cleaned any that had adhered to the studs before installed the nuts and torquing the whole sandwich together.
Result: One stud failure from corrosion in 44 years, which was easily detected on a routine inspection and replaced on the next haulout. The truth is these units are so glassed in they would remain water-tight even if both studs corroded away completely since no part of the stud is exposed to exterior of the hull.
I don’t wait for a haulout to service the units and their rubber bungs. Just remove the drain hose from the top of the unit, stuff a rag in the top to keep water from rushing in and with the lever in the off position unscrew the fasteners holding the end plats on and slowly pull out the rubber bung. As the bung comes out push the rag further into the now open unit. Yes, you will get a little wet. I use a clamp to hold the rag in place and minimize the water ingress while completing the maintenance. The rubber bungs tend to swell over time making them harder and harder to turn smoothly from opened to closed, I do a very light sand on the bungs before reassembly with some kind of waterproof lubricant.
I spoke with Groco a few years ago when they discontinued the manufacture of that unit and the replacement bungs. Apparently, there is no after-market source either so take care of yours and they will last a long time. Owners of cored-hull boats might try grinding away a foot or so of surface and core material from the inside of the hull and laying it up with multiple layers of cloth and epoxy resin to build a solid base for the direct mounting of the seacock as I have done on a solid hull.

 

[armando]

We had all cone Seacoks in a not very easy place to move at list once in a month. Always very difficult to open and close. We decide to change all the Seacoks and put instead Ball Valve TruDesign. no corrosion, no electorolysis. I use Load bearing collars in some of them in order to reinforce it. Now it is absolutely smooth. These are from New Zealand.
https://www.trudesign.nz/marine/products

 

[catalinajack]

Okay, I now know that there is no need to replace these seacocks. I learned that refurbishing the rubber plug can be done in the 2ater by tapping a wooden plug into the cavity. Then, lightly sanding smooth the bump on the rubber that is making rotating it within the body difficult, lube and reinsert. I will add a grease fitting in place with the drain plug for regular lubing.

 

[ProMaritime]

Hey Jack, I tried the grease fitting in place of the drain plug thirty years ago but didn't find it as effective as just removing the plug and sanding and greasing it periodically.

 

[catalinajack]

Hey Jack, I tried the grease fitting in place of the drain plug thirty years ago but didn't find it as effective as just removing the plug and sanding and greasing it periodically.

Good to know. I won't bother with the grease fitting.