Help identifying valve / fitting

Anyone have an idea as to what the fitting circled in red is? I've just replaced my bilge pump and have no operation as there is something mechanical at this fitting that is stopping flow. New to me boat so unsure how long it has been like this. The one pictured is for the rear bilge, it allows water to exit just fine. The one that has an obstruction is just a nightmare to access on the port side of the port engine, I can just touch it if I lay over the transmission and exhaust.

I've gotten in my dingy and went to the outside of the hull and poked a screwdriver in the thru-hull, the obstruction is definitely between the seacock valve and the thru-hull. It is also solid like metal and sealing the outlet 99%+. With a 2000GPH rule pump I can just get a drip through it.

Anyways, before I go and pull up the salon floor to try and access this thing, I'm hoping there may be an easier way to fix or disable it if it. Step one is figuring out what it is. Both of my bilge pumps have this fitting, no other thru-hull has it.

Does any of the electrical wiring go to the mystery fitting? If so, where does it originate?

Maybe a check valve??? Cannot say I have seen that before.

No wiring, just old stuff that I'm in the midst of tidying up that's been "draped" over it. I'm thinking check valve but unsure. There is a approx 25mm removeable cap on top but unsure what that would do. No physical levers or anything on it. With it's location I'm really reluctant to touch it without a fix but do need my bilge working.

Well, as soon as I started doing a google image search for raw water bronze check valves I've made a bit of progress. Looks like one of these:

http://www.challengervalves.com.au/...wing-Check-BBRG061-QAD2065-REV-5-21.08.19.pdf

Why in the heck they are there is beyond me but would appear that the construction may allow for the inlet hose to be removed and a screwdriver or something similar to be used to open the gate back up. Possibly remove the pin for the gate as well. I think I'll give it a shot and try to remove the cap, pin and remove the gate and then put the cap back on so it's just a normal thru-hull with seacock and no check valve. KISS.

Maybe take the current hose off the pump and run a temporary hose overboard until you figure out a way to fix this one.

Well it looks like one of these.
https://www.valvewarehouseaustralia...LkrztBgtt8nnvcEiWZCKdQOdLrTc3lB8aAmz9EALw_wcB

But rather than replace it, I think I would prefer to remove it and have a vented loop above the waterline, and double clamps on the hose nipple.

In addition, I dont like the look of that thru-hull fitting. I'd want a flanged one, or at least some kind of thickened area around the hull penetration. You might like to do some more research on this, and this article is a reasonable start.

https://marinehowto.com/seacock-failure-testing/

Thanks all. I'd have to agree with Insequent. I think I'll try and pop off that cap and remove the gate in situ. Alternatively looks like a screwdriver from the inlet side would open it back up. Next time I have the floor up it will go to a hose barb. They are well above the water line.

HGR said:

Thanks all. I'd have to agree with Insequent. I think I'll try and pop off that cap and remove the gate in situ. Alternatively looks like a screwdriver from the inlet side would open it back up. Next time I have the floor up it will go to a hose barb. They are well above the water line.

Click to expand...

OK, that takes a lot of issues away.

I think I have one of those valves on the inlet line for my hot water system. There it makes sense - prevents hot water backflow when a cold faucet is turned on.

But to have one exposed to salt water, that can fail in the closed position as one of yours did, is not something to have on a bilge pump outlet hose!

Looks like a swing type check valve.

I believe its a brass swing gate check valve also, and needs to be removed. Brass can corrode is salt water to the point where the bilge pump doesn't have enough pressure to open it. Bilge pumps typically operate at less than 10 PSI at the pump and diminish in pressure 1 PSI for every two feet above the pump.

Ted

I have some of those. It’s a check valve. Can’t for the life of me figure out why someone would install it there.

Also find the application of a valve on a bilge pump discharge above the waterline odd. When would you want to close the valve?

It's a check valve and it's obvious purpose is to get a dry bilge; when the pump shuts off it's to stop the water column in the hose from flowing back into the bilge. It probably did that when first installed, now it has caused the bilge pump system to fail entirely.

Just say no to check valves!

How high is discharge above water line?

If high enough, make that check valve go away. Remove the whole thing. You can remove the internal disc, but anyone that sees it will assume it is a functional check valve. Best to make it go away.

Agree about what it is, a check valve that should not be there. If the outlet is high enough above the water line then remove it entirely and install a hose adapter type through hull or adapt a hose adapter fitting to the existing through hull. Groco and Buck ALgonquin make good units in many different sizes along with fittings to adapt to the through hull.

If after bilge pump shut off water flow back is a problem then use another pump that can dewater to a very low level. THey are out there.

I did my own with an old Jabsco small diaphragm pump with the BILGE PUMP VALVES. With no pressure being held the pumps do a good job for many years. Mine pushing 20 with no need for re/re. The pump is much older. I added a small strainer to the suction hose end to reduce junk pick up. What does get through the pump can pass on. Just be sure the pump has the actual bilge pump valves. These have much larger, coarser openings to pass small junk. THe valves for the pressure system have small openings which will clog after a while.
They can be found used often where used marine equipment is sold.

There are other pumps though made specifically for this purpose although I don't pay attention as I have several of these little Jabscos for various other jobs so some spares.

Some bilge pump do use a simple plastic in line check valve. That’s just to keep the pump from cycling on/off as the water falls back down the hose. I can’t see any good reason to have an over rated check valve along with a ball valve in that application. Some sailboats have them on emergency pumps due to the boat healing over while sailing. Get rid of all that crap and let your pump work as it should.

NO check valves nor isolation valves in the bilge out let hose.
Check valve jam and a good surveyor would gig you on those.
Take the check valve and isolation out of the line and all your problems will disappear.

Per a vented loop, not so sure that is necessary. Your overboard outlet is above the water line, the standard bilge pumps are rated at zero head. You do not want anything to obstruct the outlet line.

Per the Jabsco pumps, from my experience, the weak point is the plastic or nylon hose barbs. Change them bronze.

I believe if the outlet is near the waterline a second is suggested by ABYC. In case of backflooding.

It’s probably a brass or low quality bronze swing check valve that has corroded shut.
While you could do away with it entirely, all commercial vessels do use check valves on overboard discharge hoses.

The top comes off to service it but pretty stiff cap sometimes. They are supposed to be checked periodically. They are usually bronze with a SS pin. Pretty simple device.

From Crane, describing their valve.
Operation
Check valves are automatic.
Inspection and Maintenance
Periodic inspection of the valve is recommended.
Repair Parts
Parts that may be considered as recommended spare parts are:
Disc, Disc holder, Hinge assembly, Cap

Tore into it. It was/is a check valve. I was able to strip down and crawl over the engine to get the hose off. Found a piece of rebar and ran that thru. The gate opened and is now jammed open. System is working as it should. Its about 300mm above the water line and hooked to a 2000gph pump.

New plan is to wait for my next haul out in March. I'll replace the thru hull with a proper metal hose barb and go straight to pump. Same in the rear where I've got another one. I get a very small amount of water in the bilges which could easily be handled by a small diaphragm pump so going that way to keep things dry.

What an epic over engineering fail.

So, you've found one PO 'DIY epic fail'. There will be more. That's what happens when you buy a used boat....

Discovering things like that and getting them sorted is half the fun of boating. That's assuming you are retired or have lots of spare time and understanding family.

I wish. I'm in my late 30's with a 3yr old daughter, just pulled an international move to 'Straya during covid and back at work full time. My boat isn't really a trawler but we cruise and fish when we can. Just love it as a hobby. Everyday a new surprise it seems. I enjoy this forum as it has sound advice and good conversation on a sane level vs places such as thehulltruth.

Agree with consensus - it's a check valve. I'd bet there is an arrow embossed on the other side or bottom. A gate valve has very little resistance to opening, but is susceptible to debris.

I disagree it is in place to keep a dry bilge - if that were the case, it would be at the bottom of the hose, not the top.

The obvious reason to put in a check valve at the outlet is to reduce chance of flooding. There does not appear to be room to run a vented loop, so this was done instead. If at all possible, recommendation would be to remove the check valve and run a vented loop somehow/somewhere.

Even though this is above waterline, it needs a vented loop. There are feasible scenarios where the outlet can become submerged and the bilge pump serves to prime the line. Backwash can overwhelm the bilge pump and lead to flooding if not worse. Seed-crystal scenarios include outlet is in a stern/bow wake when underway, or severe rocking of the boat at anchor/dock due to storm conditions.

If desire is for a dry bilge, run a second, small bilge pump with smaller hose. Better yet, fix whatever the source of water may be.

Peter

It's a swing check. GET RID OF IT! Don't replace it, it will ultimately fail. It's probably bronze, but if it's brass, it needs only to be in contact with seawater, it will self-destruct as the electrolysis between the components of the alloy will leach out enough of the metal that it will become unstable and simply crumble. NEVER BRASS in contact with seawater.
If the function is backflow prevention, find a way to employ a vented loop.
There's nothing unusual about having a valve on the thru-hull, it can be closed to isolate the thru hull and mitigate flooding in an emergency, but the fitting must be able to withstand the shear stress per ABYC standards. Worthwhile to check into before replacing it. Easier to do it right than it is to do it over.

My bilge pump overboards appear to be 6-8 inches above the water line. If I am getting back flow, I am in real trouble because the boat is really sinking.

The disadvantage of a centrifugal pump is the output. The getter the distance from the pump to the overboard, the less volume the pump will pump.

The next step up is a diaphragm pump such as a Jabsco pump. High volume
But, if you want a real bilge pump, positive displacement.....
I dont know of any company that makes one for pleasure boats. I suspect, if they exist, they will be very expensive. Or a gear pump or lobe pump.

Maybe the PO was a sailboater and was afraid of back flow while heeling so he put in a check valve and a hull isolation valve. That is the only explication I can think of.

Swing check. I would guess the builder felt he needed it because the outlet is close to the waterline without a rise above the outlet. If the outlet was to be held underwater due to listing, the sea can reverse flow into the bilge. So a working check valve would prevent that. The big problem with the check valve is what you found. They stick. Closed and no bilge pump flow. If the CV is at the pump with a long length of hose full of water above it, the standing water can prevent it from opening. Sticks open and you get back flow.
So in your case only, because there is no headroom for a riser loop and close to the waterline outlet, I would renew the original configuration with a real seacock and backing plate. Put it on your monthly test checklist to verify opens and closes properly.

The through hull lock nut is ready to fail.
The hose is ready to be replaced.

I had a severe back flow problem on my sailboat when I first got it. The 1 1/2" discharge hose was about 20 feet long and held enough water to restart the pump when it flowed back. The pump would push the same couple gallons of water back and forth all day long. I fixed it by adding a small pump with 3/4" hose and as short a run as possible. Only holds a few ounces of water. I also raised the big pump's float switch about 4" higher so it will only turn on if the small pump can't keep up. Small pump handles nuisance water and the big pump hasn't come on since. No more back flow.