Skin fittings and sea cocks

[Altea]

There has been a lot of publicity lately about poor quality brass sea cocks and skin fittings. Part of the problem seems to be that when a sea cock corrodes, it may not be possible to turn it off, or it may simply break, with no clean hole to plug with a wooden bung. Also, removing the sea cock may disturb the skin fitting and lead to a replacement of that as well. As one thing always seems to lead to another, it may even be necessary to drill out the fitting. What could be a simple replacement turns into a major piece of work.

I am planning to replace some skin fittings and sea cocks. The tradition seems to be always to have the seacock directly attached to the skin fitting, often in an inaccessible place. Is there a case for attaching a length of hose direct to the skin fitting, double clipped of course, then having the sea cock in a more easily accessible place further in-board?

Then if the sea cock fails it can be removed without disturbing the skin fitting. If the boat is in the water, the hose can be unclipped and easily bunged. As compared with the danger of heaving on a stuck sea cock and breaking it off or breaking the seal of the skin fitting, with no easy way of bunging, or fixing a leak.

If the sea cock is more accessible it will also be easier to turn it off when leaving the boat.

There does not seem to be much greater risk of the hose failing than there would be with the hose attached to the seacock in the traditional layout. Obviously there are two more jubilee clipped connections, but they seem to be very reliable compared with sea cock failure.

Any thoughts or experience very gratefully received.

[gabilo]

Does not seem a good idea to me, in my opinion you want to close off anything before a hose.
The hose will probably always be the weakest link.

[nigel1]

I would not advocate hose between thru hull and valve, especially in cold climates with some risk of the water freezing in the hose.

[Dave852]

Just move the through hull so it's in a more accessible spot. I just replaced 12 of 16. 12 because I eliminated 4. While I was at it I relocated 5 of the 12 to different spots for one reason or another.

[donradcliffe]

I would not recommend hoses before the valves, period.

Its not that hard to remove a skin fitting--it takes less than two minutes. Just use a 4" grinding wheel perpendicular to the fitting and rotate it 180 degrees to grind off the flange, then drive the remainder of the fitting and the seacock into the boat.

[delmarrey]

The purpose of seacocks is so one can remove a corroded skin fitting by simply unscrewing the old and in with a new. Quality bronze seacocks last a long time under normal conditions. Brass valves I'd dump after 1 year.

Another point is the valves should be lubed and exercised on a regular basis. A thruhull below the waterline w/o a valve attached on the opposite side goes against most certifications. Do you have insurance on the boat?

[robert sailor]

If you feel that brass fittings need to be replaced every year you've set out a lot of work for Europeans as virtually all of their boats are built with brass rather than bronze. When you build down to a price some quality has to be removed.

[HopCar]

If you're going to replace your skin fittings, do it right.
Use a proper flanged seacock mounted to the hull. That way even if the skin fitting were to corrode away no water would enter the boat.
Here is a picture of what the set up looks like.

Seacocks by Groco and Apollo Conbraco
Starting from the bottom you have the thru-hull (skin fitting), then the flanged seacock and on top the tail piece (hose connector).

This setup is much stronger than just screwing a valve onto a skin fitting.
The skin fitting has straight threads and the valve has tapered threads. It will work but it's a weak connection. A proper flanged seacock avoids this problem by having straight threads for the skin fitting and taper threads for the hose fitting.

All of the major US manufacturers of seacocks, Groco, Apollo, Perko, Buck-Algonquin, use 85-5-5-5 bronze. They should last the life of the boat if you give them just a little maintenance.

Another option is to use a Groco Flanged Adapter. It allows you to use a ball valve but avoids the problems of mismatched threads.




Groco Flanged Adapter IBVF

If you have trouble finding what you need, I'll be glad to quote you with shipping to the UK.
You can email me through my website; www.hopkins-carter.com

[Altea]

Thanks everyone. I will be sticking to the traditional arrangement.

[NRosenthal]

"I just replaced 12 of 16"
Perhaps one should consider the number of thru hulls. Not counting depth sounder and speedo transducers I have only 3 underwater thru hulls, on a 45' sail boat. All with bronze sea cocks. Raw in is to a manifold with separate sea cocks, raw out also to a manifold with sea cocks. Of course septic out on a separate sea cock. I have never understood the desire to put holes in your boat. I should mention 2 cockpit drains and engine exhaust are on sea cocks above the water line.

[Cheechako]

The Theory is that the value of the seacock is in it being able to stop water flow at the hull. So moving it away may have more risk. However metal boats do that, they put on a standpipe and the valve goes above waterline. It's all about confidence in your materials I suppose. As you mentioned, a plug located at each thru hull fitting could replace the valve in some peoples minds.

[S/V Alchemy]

No love for standpipes?

[Terra Nova]

Originally Posted by Altea

...Is there a case for attaching a length of hose direct to the skin fitting, double clipped of course, then having the sea cock in a more easily accessible place further in-board?...

Not just no--HELL NO!