Seacock Question

[Maine Sail]

Originally Posted by s/v Jedi

Yes, that looks very good... I assume they must still drill the holes for the fasteners? Also, what is the material used within that square?

The single seacock that was fitted from the factory on Jedi (= TPI Newport) was in a section of solid fiberglass. The hull has many parts where the balsa core is tapered away to solid glass, like around the keel, chainplates, deck-hull joint etc. The thru hulls in the photo above are additional ones, so I had to deal with the core.

ciao!
Nick.

Morris is using a lot of Marelon these days but still build with bronze when asked.. The Marelon OEM valves are not through bolted..

[osirissail]

Yes the new Marelon Seacocks for OEM have a different thread bored into them and are called "king-nut."
Here is an excerpt from the tech sheet: http://www.forespar.com/pdf/93Series...stallation.pdf

"“93” SERIES THREAD FORM; The thread form used on these thru-hull fittings and king-nuts is a non-tapered buttress type of thread design. This thread form has a higher load carrying capacity, particularly for polymeric materials. Warning, a standard pipe threaded thru-hull fitting will not fit with the king-nut on these valves. For a standard pipe threaded thru-hull fitting, use our valves that have standard female pipe thread outlets instead of a king-nut base. A buttress thread design with the same amount of clearance as for a conventional pipe thread will give the impression of greater looseness. However, when the joint is taken up tight, there is a greater area of surface between threads with the buttress thread form. As with any threaded pipe assembly, Teflon® tape should be applied to the thru-hull threads for a watertight connection.
KING-NUT INSTALLATION; The fully assembled valve is threaded onto the bedding coated thruhull fitting and tightened down by turning either the thru-hull fitting or the king-nut/valve assembly. A firm, hand-tight mount is sufficient, but if preferred, the nut can be torqued to a maximum of 12
foot-pounds. If it is desired to additionally fasten the king-nut to the backing block with screws, there is provision for such, but it is completely unnecessary. On the backside of the king-nut there are four (4) blind ¼” holes. These may be drilled through to the front side before installation t o
allow for round-headed screw fasteners."

However backing plates/boards/blocks are required if the hull surface is not flat. - "BACKING BLOCKS: A backing block or an equivalent structure molded integrally into the resin/glass hull lay-up is required for installations on all non-flat hull surfaces. This is also recommended procedure for flat surfaces as well. For wood backing blocks, white oak is a commonly used wood. There may be other suitable materials as well."

[Blue Stocking]

"Buttress-type thread" eh. SO if one plans to travel afar, one would be wise to carry a spare set of all thru-hulls and valves. Good marketing ploy.

[osirissail]

The "OEM" versions are not designed for "aftermarket" installations. The normal Marelon Seacock in the boat stores has not changed its threads and is still compatible with most all versions of Through-hull fittings.
- - But with either version, personally I would want the seacock to be "flanged" and "bolted" to the hull. There are just too many ways and things that can impact/hit the units and attempt to break them off leaving a nice clear hole for seawater to enter.
- - But a properly installed non-metallic seacock and through-hull should last as long as the boat and not need replacing. - Maintenance, greasing, cleaning, etc. - yes but not replacing.

[Maine Sail]

Originally Posted by Blue Stocking

"Buttress-type thread" eh. SO if one plans to travel afar, one would be wise to carry a spare set of all thru-hulls and valves. Good marketing ploy.

One reason why I use the Groco flanged adapters. You can find NPT valves and install them in-water if necessary in about 5 - 10 minutes..

[Blue Stocking]

Originally Posted by Maine Sail

One reason why I use the Groco flanged adapters. You can find NPT valves and install them in-water if necessary in about 5 - 10 minutes..

To quote Gord, Indeed

[S/V Alchemy]

It would indeed be necessary to do it in five to ten minutes!

[motion30]

Mcmaster carr .com has fiberglass sheets in many sizes

[Seahunter]

Originally Posted by shamrock

Is Starboard acceptable as a backing plate?

Nothing sticks to Starboard and it's brittle. Use marine grade plywood soaked in epoxy or resin and SikaFlex (best) or 5200 as a sealant.

And do Bronze sea cocks with stainless ball valves increase the need to be bonded because of the two metals in the valve, where as a fully bronze old style with the barrel cone valve being bronze as well reduce the need for corrosion protection?

All through hulls need to be bonded.

I know there is a debate on bonding or not, and this is not the nature of my question, only whether the newer type seacocks introduce an additional type of corrosion risk because they contain 2 types of metals.

Multi metal fittings just corrode faster than single. Not that single metal (or plastic) do not corrode.

[Maine Sail]

Originally Posted by S/V Alchemy

It would indeed be necessary to do it in five to ten minutes!

Not when you plug the thru-hull from the outside.... A Forespar TruPlug works great for this just as a kids Nerf ball does... With the TruPlug you can attach a lanyard so you don't need to make a second dive... Still a LOT easier and gobs faster than a haul-out and full seacock R&R....

[S/V Alchemy]

Actually, I had to do this at dock with a cockpit scupper sea cock. I dove on the boat and hammered in a tapered plug with some foam around it. Due to the "ears", it didn't do much, but it helped. Then I replaced the sea cock rapidly, opened the valve...whoosh!...and rammed a piece of threaded rod down the passage. Then I closed the cock and let the bilge pump deal with things as I clamped on the hose.

Yes, I was down a threaded rod, but the tapered plug bobbed to the surface and is still tied to the base of the thru-hull.

I will check out the Forespar plug, however. Thanks.

[NahanniV]

Would Grade C phenolic make an appropriate backing block for a seacock.

My local plastic supplier has it in stock and I can get it for next to nothing compared to G-10 (which would be a special order).

Thanks,
John.

[rtbates]

Originally Posted by Mark Zarley

The ancient all brass tappered seacocks are a maintance nightmare. To keep them in tip top shape the tappered surfaces need to be taken apart and throughly cleaned yearly. Cleaning can invlove a light lapping. That said the brass,stainless-nylon is the top of the line for a metal valve.

From my experience with SPARTAN ALL bronze seacocks your response is somewhere between total BS and maybe 90% BS.

I have a Cape Dory and as such talk with CD folks all the time as well as the CD webpage. No one has your experience with Spartan seacocks that I know of... Mine are 27 years old, original and they all work AND DON'T LEAK A DROP.. I take em apart for maintenance every 5-10 years!!!

[MarkSF]

Originally Posted by rtbates

From my experience with SPARTAN ALL bronze seacocks your response is somewhere between total BS and maybe 90% BS.

I have a Cape Dory and as such talk with CD folks all the time as well as the CD webpage. No one has your experience with Spartan seacocks that I know of... Mine are 27 years old, original and they all work AND DON'T LEAK A DROP.. I take em apart for maintenance every 5-10 years!!!

A couple of my Wilcox-Crittenden tapered seacocks started to leak after 28 years. They are the two that are cycled most often, so subject to the most wear. I had them replaced as one was located so that, if it leaked, the water soaked into the teak cabin sole.

So they do wear eventually, but not quickly. They also fail in a way (slight leak) that is pretty harmless.

[casual]

While on Seacocks ,I,removed my thru hulls and Gate valves not a seacock on the whole boat,any way the valves have bronze handles not like the new stainless ones no identifying marks.Anybody know where youu can get replacement parts as they are all in good shape.Thanks