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 Post subject: Galley Thru Hull replacement.
PostPosted: 01 Sep 2020 15:18 
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Tactictian

Joined: 16 Mar 2007 16:10
Posts: 116
I need to replace my thru hull and sea clock thatís located under the galley sink. Iíve have greased the ball fitting for the last 3 years since Iíve owned the boat, and itís a bit better, but itís still very stiff.

I want to replace to meet ABYC standards, that has a triangular base and a backing plate.
Hereís my questions..
1.) My existing seacock is not bonded. Can this be done with a new one? What do you bond to ?

2.) I think the galley sink thru hull is one and a half inches but not sure.

3.) Should I go with bronze or Marlon?
Iím leaning towards bronze but not sure which type/brand /model is the suited for this thru hull.

Thanks in advance for any and all feedback, advice, & comments.

Nick,
S/V Angela Mia
#336
Lake Superior.


 
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 Post subject: Re: Galley Thru Hull replacement.
PostPosted: 01 Sep 2020 18:41 
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Skipper

Joined: 16 May 2009 08:06
Posts: 173
Iím surprised that it isnít bonded. I have hull 324 and there is a piece of solid copper wire that runs continuous through the boat tied to all the underwater metal and the mast step. Definitely factory installed. I think 1-1/2Ē is correct but the boat is a long way off to measure. If you go with Marlon, obviously you donít need to bond it. There are a few manufacturers of the bronze through hull fittings and I donít have an opinion of one over another. Consider when you do the plumbing, running a 1-1/2Ē to 1/2Ē T fitting in the drain and tie the other end (with a 1/2Ē ball valve and appropriate reducing T) into the raw water circuit for the engine (to the seaward side of the water strainer). That way, you close the sink drain, close the engine intake and open the 1/2Ē ball valve and pour antifreeze into the galley sink to winterize the engine cooling system.


 
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 Post subject: Re: Galley Thru Hull replacement.
PostPosted: 02 Sep 2020 12:35 
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Skipper

Joined: 04 Aug 2013 13:33
Posts: 293
I agree that all metal should be bonded. I replaced mine with groco seacocks with the triangular flange base. Easy to find info on them. They come with a fitting for attaching the bonding wire. Groco has a model where the base flange has threads to receive the ball valve and where the flange is all part of the body of the ball valve.

The bronze fasteners can go through the backing plate that is secured to the hull, or through both hull and backing plate - either acceptable according to installation instructions. I think ABYC says it should withstand a 500lb pull, so I went with flathead countersunk fasteners through the hull.

My recollection is that the sink drain is 1 1/2".

I put Marelon thru-hulls and seacocks in my old 30-footer and had no incident after 25 years, but for a Tartan 37, I put in bronze. Attached is something I found online when researching this topic.


Attachments:
File comment: General info on thru-hull & seacock
Seacock & Thru-Hull Primer Ė Marine How To.pdf [4.36 MB]
Downloaded 25 times

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Dave Lorick
Lunacy #198
Tampa, FL
 
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 Post subject: Re: Galley Thru Hull replacement.
PostPosted: 03 Sep 2020 13:16 
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Tactictian

Joined: 16 Mar 2007 16:10
Posts: 116
Thanks guys for your comments. Good stuff!
Iím going to go with Groco.
They make two types.
One with a brass ball valve that is chrome plated. Another with a Stainless Steel valve which is more expensive.
I always thought you donít want to mix brass and bronze fittings. Not sure how well the chrome plating would hold up in fresh water - stray current...

Any thoughts?
Cheers,
Nick.


 
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 Post subject: Re: Galley Thru Hull replacement.
PostPosted: 03 Sep 2020 16:31 
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Skipper

Joined: 04 Aug 2013 13:33
Posts: 293
Brass? Brass is an alloy of copper and zinc. Zinc is a popular anode material that protects other metal from galvanic corrosion because it corrodes readily. I would be surprised if Groco put it in their bronze products. Here is a link to one model of seacock: https://www.groco.net/products/valves-s ... /bv-series This says the ball is stainless steel.

I think the pdf I attached above cautions against use of brass.

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Dave Lorick
Lunacy #198
Tampa, FL


 
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 Post subject: Re: Galley Thru Hull replacement.
PostPosted: 03 Sep 2020 16:39 
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Skipper

Joined: 04 Aug 2013 13:33
Posts: 293
You're right Nick - Groco FBV series has chrome plated brass ball.

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Dave Lorick
Lunacy #198
Tampa, FL


 
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 Post subject: Re: Galley Thru Hull replacement.
PostPosted: 04 Sep 2020 22:49 
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Skipper

Joined: 29 Dec 2006 09:38
Posts: 579
NP336 wrote:
I need to replace my thru hull and sea clock thatís located under the galley sink. Iíve have greased the ball fitting for the last 3 years since Iíve owned the boat, and itís a bit better, but itís still very stiff.

I want to replace to meet ABYC standards, that has a triangular base and a backing plate.
Hereís my questions..
1.) My existing seacock is not bonded. Can this be done with a new one? What do you bond to ?

2.) I think the galley sink thru hull is one and a half inches but not sure.

3.) Should I go with bronze or Marlon?
Iím leaning towards bronze but not sure which type/brand /model is the suited for this thru hull.

Thanks in advance for any and all feedback, advice, & comments.

Nick,
S/V Angela Mia
#336
Lake Superior.

Well, Tartan did not originally install it to current ABYC standards and I do not know precisely what is required in the latest regs. I am not sure why you would need to follow them for this. I would use the instructions in Nigel Calder's maintenance book. ABYC specs change fairly frequently. One thing is that you cannot use any wood or porous material for a backing plate as Tartan did. Tartan used (at least on my hull #373 Groco flush mount through hull fittings with marine ball valves on them--also I believe a no no in current ABYC--but most of the lobster boats ignore this and pass inspection and have a great deal more electrical abuse than your boat. I have replaced all of mine with essentially the same thing, but used a piece of laminate for a backing plate. The Groco Flush through hull fittings are a bitch to remove. You can try to turn them out with a special step wrench from the outside (you will need to expose the whole outside of the fitting which is likely buried under layers of paint and maybe some glass if you have flush mounted ones. I did not try to "save" the hole for the through hull. I ended up drilling the suckers out, refilling and glassing over the holes and starting all over again to make it all new and clean--and I made all except the sink drain larger (I think it was 1" ID) It is a big job. I would not recommend merely replacing the ball valve if that is the arrangement you have and putting it on the old through hull fitting. The through hull fittings are a weak point and corrode. I had a pinhole leak in one of mine that bugged me for a year til I found it under the sink. This led me to replace them all.

Using marine ball valves like Tartan did is probably not ABYC approved, but I think it is the right way to do it in this particular boat. They may look like the valves you see in Home Depot THEY ARE NOT. You need the marine type they sell at Defender and Hamiltons. The other challenge is that the pipe thread on the through hull fitting (male) is slightly different than the female on the ball valve. I think it will work, but I took mine to a machine shop and had them adjusted to perfectly mate--it can be done with a tiny amount of rethreading the through hull fitting in a couple minutes--this may have changed and the threads may now match, but check them and do not just force them on. If someone has installed the old lever valve through hull fittings with the three bolts through the outside, I pity you and I cannot help you. These are probably what ABYC wants and I think they are ridiculous overkill and create an opportunity for more leaks. I probably have pictures somewhere if you get stuck. I can coach you through the process if you want to do what I did.

You can use your own judgement on bonding. Nigel Calder has gone back and forth over the years about the bonding and no bonding. The original Tartans had some of the through hulls bonded and some not. Some say bonding accelerates corrosion. The heavy copper wire in the bottom of the boat is most likely just to direct a lightning strike from the mast step to your engine and prop to minimize what it takes out elsewhere---in my boat they had tagged this to a keel bolt and the strut, but this was not really for bonding purposes. I have owned my boat for 28 years and sailed a lot (lived on it for a couple years) and never had an issue that I thought bonding would help. But maybe I was just lucky. I think it is good to look at ABYC requirements (if you can figure which ones apply to your boat) but you also need to use your head to do what makes sense. Nigel Calders maintenance book is generally my go to, but he has recently gone over the edge with some of his stuff. I guess he needs to write articles to keep food on the table.
Let me know if you want some pictures. Removing the old through hull fittings was the worst part. I would consider doing more than one at a time. Maybe all of them. When the boat is out of the wather and you have all the tools there, I would not wait until they leak. Don't use 5200.
Ray Durkee


 
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 Post subject: Re: Galley Thru Hull replacement.
PostPosted: 06 Sep 2020 18:01 
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Tactictian

Joined: 16 Mar 2007 16:10
Posts: 116
Dave,
I couldnít belive either about Groco offering a marine grade seacock with a chrome plated brass ball valve.
Iím going with the Groco triangular base with the bronze ball valve. Itís the most expensive seacock out there, but Iím not going to cut corners on a thru hull replacement to save fifty bucks.

Ray,
Thank you for your comments.
I have Nigelís Calderís book and recall being a bit confused by his somewhat inconclusive thoughts about bonding..
Groco makes an impervious laminate backer plate that can be epoxied in place. I also canít believe that ABYC gives
two options of attaching the backer plate. I have no plans on thru bolting thru the hull. Bolt Spacing i think is too close and may weaken the hull, and you have three additional potential sources of leaks per thru hull. Why go there?
Bolt heads can be countersunk into the backing plate and epoxied.
I also agree that 3M 5200 should not be used for bedding thru hulls. 3M 4200 is a better choice in my opinion for this application.

If you could share you thru hull photos that would be great! Iím sure others on the forum would also have great interest.

Best,
Nick.


 
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