Sea Cocks

[Mycroft]

Maine Sail has several outstanding articles on thru-hulls and seacocks that are not to be missed. Including a method of installing a backing plate without thru-bolts.

Compass Marine How To Articles Photo Gallery by Compass Marine How To at pbase.com

[Boatyarddog]

Originally Posted by Reverie27

Thanks for the tip, amazingly enough, given the amount of time I spend trolling the Internet for boat info, that I completely missed the Forespar manual. I am relieved to hear that I do not have to drill additional holes in my hull. Now I just have to find source for quarter or half sheets of marine plywood, as the specialty lumber supplier only sells full sheets, way more than I need for three Seacocks pads. A line on. A source in Canada, as the exchange rate is not favourable right now, would be much appreciated.


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I have the same problem, at times I'm prone to waterproofing furniture grade hardwood ply, for Marine Ply because finding a Half Sheet😳
Actually Forespar mentions this as well, coating the marine ply with epoxy, but it's not really nessessary to use Marine Grade if you maintain and look at the area of install. If it's a wet area, best use Marine grade Ply.
If not, epoxy coated, and painted works for a long long time.
You can use Starboard as well, be sure to scuff it good before sealing.
Never rots, you can get smaller amounts of it to.
http://www.defender.com/category.jsp...341&id=2303346


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[goboatingnow]

Originally Posted by crazyoldboatguy

Can you even buy brass seafocks?

DNZ brass yes , Blake's are DNZ brass


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[crazyoldboatguy]

Originally Posted by goboatingnow

DNZ brass yes , Blake's are DNZ brass


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A brass that isn't brass.

[a64pilot]

Originally Posted by rwidman

I hope nobody actually has brass seacocks or brass anything that comes into contact with seawater. Bronze is the proper metal to use. Marelon is the proper non-metallic material to use.

I've been told, but have not verified that some French boats have brass thru-hulls etc.
Maybe it could be Red Brass? Which I think is actually Bronze?

Only brass I want on my boat may be some kind of decorative thing, but nothing that gets wet, I don't even want it on my plumbing if I can help it

[crazyoldboatguy]

Originally Posted by a64pilot

I've been told, but have not verified that some French boats have brass thru-hulls etc.
Maybe it could be Red Brass? Which I think is actually Bronze?

Only brass I want on my boat may be some kind of decorative thing, but nothing that gets wet, I don't even want it on my plumbing if I can help it

Or Naval Brass - which really ain't brass. It can get very confusing for folks. Easier to just stick with bronze. But then there is bronze and there is bronze. I suspect most manufacturers of marine thru fittings would eschew any type of material that would quickly deteriorate in seawater.

I had a propellor shaft fabricated by a local machinist once - a long time ago before the interweb. I gave him the old one for comparison and told him I would find the bronze stock and get it to him. I called him a few days later to tell him I had found the bronze rod and he told me he had finished the shaft. "I made it out of brass, that's the proper metal - you don't want to use anything else underwater".

It was 2 days before splashing. I put the shaft in but replaced it the next season. I feared the prop would fall off the entire summer.

[bretto55]

I have brass/bronze thru hull seacocks.

[cal40john]

Originally Posted by bretto55

I have brass/bronze thru hull seacocks.

There are many alloys of brasses and bronzes. Brass is mostly copper and zinc. Zinc being a good sacrificial metal will dissolve out, leaving a weak easy to break metal.

Bronze is copper alloyed with other metals, with little or no zinc. Holds up much better.

Is your seacock a combination of brass and bronze?

[boatpoker]

All European boats have been produced with brass ball valves and nickel plated, brass ball valves (not seacocks) for many years and many of those are NPS throughulls with NPT valves.... incredibly stupid. The vaunted CE Standards only require such fittings to last five years .... even more stupid.

Go to Stoopid Tricks By Boat Builders and scroll down to the bottom for a little more info.

[crazyoldboatguy]

Originally Posted by bretto55

I have brass/bronze thru hull seacocks.

I'd like some of those. Where'dya buy 'em?

[boatpoker]

Originally Posted by bretto55

I have brass/bronze thru hull seacocks.

What is brass/bronze ?

[GordMay]

Originally Posted by boatpoker

... The vaunted CE Standards only require such fittings to last five years .... even more stupid.
Go to Stoopid Tricks By Boat Builders and scroll down to the bottom for a little more info.

The European standard for metallic seacocks and through-hull fittings (IS0 9093-1) states:
“Materials used shall be corrosion-resistant...”
The directive defines corrosion-resistant as:
“a material which, within a service time of five years, does not display any defect that will impair tightness, strength or function.”

[boatpoker]

Originally Posted by GordMay

The European standard for metallic seacocks and through-hull fittings (IS0 9093-1) states:
“Materials used shall be corrosion-resistant...”
The directive defines corrosion-resistant as:
“a material which, within a service time of five years, does not display any defect that will impair tightness, strength or function.”

Thats pretty much what I said. "corrosion resistant" for "five years" is how Beneteau, Dufour, Jeanneau, Hanse and Bavaria et al interpret that. As shown in the article link I posted, their lousy brass fittings often don't last close to that long. Add a little electrolytic action and they can disappear very, very quickly.

Thats an incredibly stoopidly written standard !