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post #1 of 9 Old 03-03-2010 Thread Starter
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Replacing seacocks and through hulls.

I would like to know if there is any way of assessing the condition of seacocks and through hull fittings? Of course safety is 1st priority but money doesn't grow on trees.

If they should need to be replaced, what brands, types and materials are recommended. I sail 90%+ of the time on a salt-water river and the rest on the ocean. If replaceing then quality( life-span, impact ressistance, etc) takes a priority over price. I have almost always found that better products work out cheapest over the long term.

One last question. Do I need to earth them? I don't use shore power, apart from charging the battery with a double insulated charger hence no earth pin on the plug. I would think this means I wouldn't have earth leakage but I go through prop shaft anodes in about 6-8 months so I think a boat in my vicinity may have a problem. Is there an effective way of fixing this?

Thanks,

Dave.

Last edited by davewild; 03-03-2010 at 08:59 PM. Reason: forgot a question
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post #2 of 9 Old 03-03-2010
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I would not worry about a bronze through hull fitting if there wasn't a lot of corrosion and as long a the seacock was operating smoothly and closing all the way, I wouldn't worry about it either.

I just ripped out the plumbing for my head and discovered that the seacock is frozen open. I've been able to get a little movement, but can't close it yet.
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post #3 of 9 Old 03-03-2010
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I agree, bonding the through hulls is not necessary. Are you replacing them because they are not opening and closing properly? Because they are gate valves? Or just because they are old? If they are real seacocks they are built for the long run and can be reconditioned if necessary. If they are gate valves I would replace without question. If you do replace them the proper way is with a through bolted base as opposed to the mushroom with a nut only method. See this link by Maine sail for the options available, method and proper backing plates (fiberglass and not wood). Replacing Thru-Hulls and Seacocks Photo Gallery by Compass Marine at pbase.com

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post #4 of 9 Old 03-03-2010
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Scrape away the verdigris (green stuff) and see what the color is. If it's gold, you're good. If it's reddish or salmon colored, your bronze is de-zincafying and will become brittle and easier to break. Scrape away a lot, it can be good gold color in some spots and salmon or pinkish in other places.

Take a look at the Groco website and look for IBVF flanges. Traditionally there has been a mismatch between thru hulls and seacocks; tapered and straight pipe threads. Groco makes a three part system. A thru hull; a flange adapter that screws onto the thru hull and provides a big flange base for support; a ball valve that screws onto the flange adapter. You then add a pipe to hose adapter to finish it off. I've done 3 so far and I like the feel of the flange base mating flush to the backing block on the hull.
Groco has illustrations and Maine Sail has pictures on his pbase website.

You have several choices on how to fasten to the backing block. MaineSail's are the best but I cheat and use lag screws into the backing block. Mine felt very solid even without the lag screws but the lag screws provide insurance that you won't unscrew the flange from the thru hull even a little bit.
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post #5 of 9 Old 03-03-2010
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Are your backing blocks fiberglass or wood?

Brian
Living aboard in Victoria Harbour
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post #6 of 9 Old 03-03-2010
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I like the Perko Seacocks, big round flange, 4 bolts, very rugged but very IMO expensive. You can get straight or 90 degree hose adapter or thread in a Tee or other fitting.


Down side is the $240 price tag. They are cheaper at sailnet but still $200.
PERKO SEACOCKS CAST BRONZE 9-0834008PLB Hose-1-1/2", Bolt Size-3/8" Shop.Sailnet.com - sailing resources, shopping, sail, blogs

Of course a really good backing block is needed for which ever seacock you use.

I did not use, but considered the Marelon seacocks. I think I might have used them if I was going to change the bolt pattern (they use 3 bolt) but there is just something about metal that I prefer.

Bonding is required on metal seacocks (all the good seacocks will come with bonding screw) if the hose being used has steel reinforcing in it or is conductive. If the hose is a plastic hose then no bonding is required. I think that is the recent ABYC standard.

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post #7 of 9 Old 03-03-2010
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I don't believe ABYC requires seacock bonding and I am not a fan of bonding them. Isolated seacocks really don't need to be added to the electrical mix. Nice seacock, the Groco flanged adaptors are a good way to go as well.

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post #8 of 9 Old 03-04-2010
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Quote:
Originally Posted by davewild View Post
I would like to know if there is any way of assessing the condition of seacocks and through hull fittings? Of course safety is 1st priority but money doesn't grow on trees.
You need to clean off any corrosion and inspect the seacocks very closely to see if they've started to dezincify from galvanic corrosion. If they have any pinkish spots, they really should be replaced.

Quote:
If they should need to be replaced, what brands, types and materials are recommended. I sail 90%+ of the time on a salt-water river and the rest on the ocean. If replaceing then quality( life-span, impact ressistance, etc) takes a priority over price. I have almost always found that better products work out cheapest over the long term.
I would recommend you read Maine Sail's excellent how to on this issue. It will answer most of your questions. It is located HERE. Per Maine Sail's post, I would also recommend using the flanged adapters. It makes replacing the seacock a lot simpler.

Quote:
One last question. Do I need to earth them? I don't use shore power, apart from charging the battery with a double insulated charger hence no earth pin on the plug. I would think this means I wouldn't have earth leakage but I go through prop shaft anodes in about 6-8 months so I think a boat in my vicinity may have a problem. Is there an effective way of fixing this?

Thanks,

Dave.
No, grounding them isn't necessary.

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post #9 of 9 Old 03-04-2010
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I used marine grade plywood. I soaked them in a wood hardener I had on hand. Soaking with epoxy would be good too
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