View Full Version : Removing old seacocks

Ronin NW
07-12-2005, 07:02 PM
I have a bad old plumbing dilemna! My wet exhaust thru-hull (above the water line on a double-ender) is an old gate valve. I haven't been able to move it for months. I finally pulled out my deck key and got it to turn, but it won't go back up. In fact, the gate seems to have sheared off from the pin. I was gonna replace it anyway, but now I can't even turn my engine on :mad: But the real problem is that I can't get the dang valve off of the thru-hull. It's about a 2" OD thru-hull, but there's a 3" or so long tube between the hull and gate valve that's encrusted in rust. It won't budge. I've tried corosion-X, WD40 (I know, pansy), and wrapping it with webbing and using my windlass handle for leverage. (Did I say there's NO space to work near this thing?)

I know a gate valve like this has no place on a boat, and now I know why! Who's got thoughts on how to get this thing off!?

Thanks in advance,

Mike Vogdes
07-12-2005, 07:20 PM
Two good sized pipe wrenches and heat is the way to go if you can pull it off safely. Get a few buckets of water and some fire extingushers just in case things get out of hand, and most importantly get someone to help, even if its just passing tools, a good helper is called for when working with torches.

Gary E
07-12-2005, 07:29 PM
Can you aim a sawzall at the valve so as to make a cut tangent to the thruhull? If you can this should allow some stress relief and then the valve will rotate off,

Or how about making plugs for the outside and the inside with a small hole at the top so you can fill the intire valve and thru hull with penetrating oil, this assumes the gate has not completly sealed, maybe make that hole on both plugs and fill from both ends.

07-12-2005, 08:48 PM
Carefull work with a saw on the valve should enable you to turn the valve with out turning the thru hull. Also see if you can dismantle the valve body without tearing the thru hull out. There is never enough room to brace your feet and really get your back into the job. :(

Jay Greer
07-13-2005, 08:32 AM
If it is fruzzed beyond removal, then you can cut off the thu-hull from the inside of the tube, using a Dremel Grinder and a fiberglass reinforced cut off wheel. Die grinder works too.

07-13-2005, 12:19 PM
Another possibility is to grind off the outer flange of the through-hull and push the remainder of the assembly in.

Ronin NW
07-13-2005, 01:32 PM
I had to come in to work this morning but maybe I'll ahve a go at this tonight. Hopefully I can save the thru-hull and just get the valve off. The torch actually sounds the easiest, if I can pull it off without catching anything on fire. I've got a smaller kitchen-grade butane torch (for the best creme brulee ever, thanks for asking), and maybe I can shield the nearby hull area with copious amounts of tin foil. A photo of myself crumpled up in the lazarette trying to work on this thing would doubtless be amusing, but you'll have to use your imagination.
Thanks so far, I'll have another go tonight...

07-13-2005, 02:43 PM
Remember! In case of fire you must be able to escape! :eek:

07-14-2005, 01:25 AM
Where's the boat located? I wouldn't mind seeing your project if it's not too far from me.

07-14-2005, 02:40 AM
Forget about saving anything. If its failed its failed and you don't want to rely on a failed part .. do you!

I'm with Jim - that's how I've done all my through hulls for years (and Barry, my shipwright mate, for decades). When I first bought my boat, I paid a yard to change the raw water engine intake through hulls and cocks. They charged 8 hours labour! If I'd been there it would have been a 30 minute job in total (as it was this year when I re-did it).

Use a 4" grinder - if you haven't got one, it'll cost you less than $20 for a throw-awy one - and "petal cut" the through-hull from the outside - ie make it look like a daisy. Cut carefully and you wont damage the timber. The petals will fold in with a tap or two from a cold chisel (or flat screwdriver).

Total time taken - five minutes.

I'd even do this on the water - given sufficiently quiet water and with one very, very important proviso - the power cord needs to be totally secured so that the tool can't reach the water without pulling out of the extension plug. Be very, very careful if you are doing it in the water!


Andrew Craig-Bennett
07-14-2005, 04:23 AM
That is very good advice.

Did mine a few years ago and was appalled by how nasty the whole thing had become - replaced with proper cone pattern seacock.

Ronin NW
07-19-2005, 04:08 PM
Okay, here we are. Since the outer hull has a bit of a counter at this thru-hull, it seemed pretty tricky to get a grinder that close to the water (it'd be under the rail of my dinghy angled upward and I'd have no purchase to boot), so I took a sawzall to get off the valve and a grinder to cut the retaining nut inside the thruhull. I've now got a bunch of scrap metal, about as much filings, and a beautiful hole in my boat.
Now I'm trying to sort out all of the valves. I definitely want bronze for this application (exhause 'may' get hot). I also need to clear the ceeling with the valve handle which is about 3" from the planking. I'm thinking about an extra-long thruhull with an extra counter nut so I can hold the seacock body at the right spot to clear the ceiling. How does such an arrangement compare to seacocks that have a flat mounting flange fastened to a buttblock on the planking?
Thanks for advice.

David McCollum
07-20-2005, 08:22 AM
Is it normal to have a valve on an exhaust fitting? My old Matthews does not have a valve, just the hose running from the engine, clamped to the tube. Did someone cut a corner here?

Ronin NW
07-20-2005, 01:56 PM
My understanding is that the valve can be shut in high following seas so as not to flood the engine (and possibly engine room) with seawatter. At least that's what a surveyor said...

Gary E
07-20-2005, 02:07 PM
I can not imagine a need for a valve to close that off. How would your engine run? The engine should have a riser on the engine so that the exhaust flows downhill all the way to the transom. Some people clamp on a rubber flaper dealie to close the tube when a wave smacks the transom.

07-20-2005, 02:17 PM
Ronin - a Vetus goose neck or muffler or both is the standard alternative to your seacock. That way you can power in a following sea when you need to. Anybody that deals with marine engines will have one for you, 90-130$ each.

07-20-2005, 03:17 PM
Never seen or heard of a seacock on the exhaust port. Sounds like trouble. As long as there is a loop in the exhaust to keep water from running up into the exhaust riser there is no need for a valve that I can think of. Install a standard exhaust fitting and clamp the hose on the nipple inside the hull.