Dysfunctional Seacock

[theonecalledtom]

How many forums can a posting title like that be completely legit?

Having been working 90 hours weeks for what feels like forever I've been starting to get the boat ready to go out again.

Here I'm going to own up to being bad. Ever since we got the boat I haven't changed the impellers. So long as the running temp seemed okay and water kept coming out the back I've pushed this to the back of my **** list. Why? Because there are warnings in my manual about doing it wrong leading to needing to rebuild the pump. That and fear of the unknown.

This year I decided to fix that. Time for a whole new approach to this. Time to conquer the fear.

So I crack open the pump case with a [small] bucket underneath to catch the expected sea water. Here comes the water. Quite a bit of pressure there - wasn't expecting that. Hmm, one bucket later still have pressure. After three buckets I seal it back up again.

I was expecting the flow to stop quite quickly - looks like the pump is below the water line but fairly high in the overall raw water system.

I make sure the anit siphon device is cracked open (but lets face it the exhaust output is above the waterline) and that the sea cock really really is closed.

Try again. This time I push the sea cock open and closed while watching the flow, no real change.

I tried tightening up the sea cock, still no change though there is now decent, but not excessive, friction on the handle.

Is the cock broken or am I missing something completely obvious?

The engine is a Universal M40 / 5432 - the pump a Sherwood something or other and the sea cock unknown, fairly corroded looking but the metal under the corrosion looks fine.

I wasn't planning on hauling out until after the summer - do I need to change plans?

Oh while I was working out how to tighten the sea cock I threaded the lock nut. It still holds the handle in place but not tightly and I wouldn't want to use it as support in an emergency.

Welcome back to the boating life Tom!

[theonecalledtom]

Wow that was really long, not just months of pent up sailing to start addressing, months of pent up posting!

[sailorboy1]

Well I have been thinking about rebuilding/replacing the impeller in my seawater pump; just to have done it when I didn't NEED to.

But if I found out that the seacock wasn't holding water I would be pretty uncomfortable. I'm not paranoid and sailed all last year with a valve that wouldn't close. But it was just the head inlet and I can stop the flow just by holding the hose in the air. If it was to the engine I don't know if I would have let it go. Last thing I would want is to have a cooling problem when I needed the engine (clogged stariner) and not be able correct it in the water.

So if me I would say to turely verify that the seacock isn't holding, and ifit isn't you got to haul and fix that puppy!

PS - on my boat I can put the hose off the seawater pump without shutting the valve as the engine is after the vented loop.

[Target9000]

The type of seacock is important. I've seen tons of posts in forums showing where people used brass (hardware store plumbing valves) as seacocks and the ball in the center will completely corrode away. It is also possible for it to just be flat out defective.

I'd definitely take a closer look at what that seacock really is and what it is made out of before moving on.

No matter what I'd make sure you have a plug tied to the seacock so that if water starts coming in you can plug it up. Good practice even with fully functional seacocks.

[theonecalledtom]

Yeah - I've got the wooden plug handy.

I'll check the sea cock closer but am guessing its a decent marine item. There was corrosion on the outside but it flaked off pretty easily with a brush / screwdriver.

One thing I'm not sure about is how much tighter I can tighten it - the lock nut threaded pretty easily which doesn't give me faith in putting much pressure on it.

[Christian Van H]

I think there are drugs for this now...