Seacock question

[saltypat]

We are troubleshooting our new old boat. It is an Endeavour 33. You loosen a bolt before opening or closing a seacock, and then you tighten the bolt.

We have ahead discharge valve which is open and does not leak. When we loosen the bolt, close the seacock, and then tighten the bolt again, it continues to weep.

Gosh, why would be a seacock leak when closed, but not when open?

Also this seacock is labeled head discharge. I am thinking this should be closed as we would use the holding tank.... I can't imagine that this should remain open......

Feeling pretty clueless about this. Any advice always appreciated.

Thanks, SaltyPat

[sailingdog]

Is it a tapered valve seacock or a ball valve seacock? From the sounds, it is probably a tapered valve seacock.

If it has any mineral deposits or corrosion on the tapered cone or the valve seat, it may leak in one position but not the other. If it is a ball valve, the same thing could happen, but I would think it'd be less likely. The other thing that could the problem is the mating surface for the tapered cone or ball valve has gotten scratched or scored, and when it is open the fluid goes through to opening, but when it is closed, it leaks through the damaged area. I would recommend that the next haul out, you take the seacock apart and inspect the surfaces of the internal parts for either damage, corrosion or mineral deposits.

[saltypat]

Saliingdog-
you are a top dog- thanks for the advice on the seacock and the stove.

SaltyPat

[dohenyboy]

I remember reading that this kind of seacock uses a rubber plug and with time the rubber plugs can get distorted and leak in one position