Bilge pump backflow?

Ron20324 · Mar 16, 2011

Either shut the valve, but hang your boat keys on it so you open it before leaving, or put a loop to go above the water line if there isn't one already.

FourPoints · Mar 16, 2011

I haven't yet installed my bilge pump, but in planning to prevent exactly that, I bought a check valve that fits the bilge hose from defender. I believe it is made by jabsco, intended as a check valve for head plumbing. If it made to handle black water, I'm sure it can handle bilge water...

Now if i can only figure out how to get the bilge hose from the bilge, under the sole through the cabin, and up to my above waterline thruhull I'll be great!

Don S/V ILLusion · Mar 16, 2011

Check vlves are generally considered a bad idea particularly on a bilge pump as they can fail and can do so at the worst time. why not just put a loop in the line at the highest point above the WL?

FourPoints · Mar 16, 2011

I plan to put a regular high loop as well (but space constraints will not allow it to be very high, 6" at most), with the check valve on the down hill side of the loop (when following the regular flow of water from the pump). The check valve will have gravity to help the water flow out through in normal operations (and hopefully not restrict or degrade the pump's ability to pump), and act as a first stop to hopefully prevent water from even making it to the loop. All while leaving the loop in place if the valve fails.

I know the valves can fail closed and plug the hose, but that normally only happens when engine room crap gets pumped out also. My bilge contents usually consistent of nothing more than melted ice water from the ice chest (having an outboard engine helps in this regard). I will not be utilizing the valve to anywhere its rated "duty" cycle (pun intended, bad joke, my apologies, couldn't resist).

MrUnix · Mar 16, 2011

Where are you discharging the bilge pump? Are you Teeing off the existing sink through-hull or using a separate through-hull? It also seems strange that it would be letting water into the areas below the cabin bunks.. I would think that back flow from the bilge line would put water into the aft bilge area, not in the cabin unless it's backing up through the sink or has a leak in the hose?!?

Cheers,
Brad

Roger Long · Mar 16, 2011

FourPoints said:
I bought a check valve that fits the bilge hose from defender.

DO NOT under any circumstances install it. Bilge line check valves with electric pumps can sink your boat a couple of different ways.

There are a lot of threads here on proper bilge piping. Do some searching and come back with any questions.

RichH · Mar 16, 2011

Probably your discharge tubing DOES NOR HAVE a 'vacuum breaker' installed in the line or the vacuum breaker isnt at the 'highest' level of the entire discharge line.

If no 'vacuum breaker' you WILL 'back flow' when the boat is heeling and the pump shuts down. The vacuum breaker MUST be well above the maximum (heeled over) water line !!!!!!! .... and the teeny valve inside the 'vacuum breaker' must be operating and not 'clogged'.

So therefore, I strongly suggest you FIRST check the tubing for the location of the 'breaker', validate that the small rubber valve INSIDE the 'breaker' is operating and not plugged nor 'deformed' AND validate that the breaker is ABOVE the heeled over waterline ... and before you send your grandchild down to see if there's a leak.

DannyS · Mar 16, 2011

I had a couple of scary moments a few years back. We were motoring to across Lake Superior to a very remote area. We just over halfway into a 35 mile trip and I went below to find 3" of water over the floorboards. Our boat squats when under power and the bilge pump discharge is just above waterline at the rear of the boat (not my design) and it goes underwater when motoring. Well, at some point,conditions became right to begin sucking water back into the boat. I didn't have the bilge pump on (automatic pump cycles every two minutes) so it wasn't helping. We ended up turning around and heading back home but once we slowed the boat down, the inflow stopped and didn't occur again. At that point, I didn't know where the water came from but I suspected it was the bilge pump. A few days later it happened again and I opened up the bilge and pulled the pump out to find water pouring out of the pump. As I lifted it, I could find waterline because it would stop, as I lowered it below waterline, it would start again.
I installed a vented loop into the system at the high spot in the line and it hasn't happened since. I can hear the duckbill squealing after the bilge pump cycles letting me know the vacuum is being broken.

All U Get · Mar 16, 2011

Roger Long said:
DO NOT under any circumstances install it. Bilge line check valves with electric pumps can sink your boat a couple of different ways.

There are a lot of threads here on proper bilge piping. Do some searching and come back with any questions.

Well last summer I had that problem while off-shore, see post. I took apart the access panel under the cockpit to find the bilge hose directly to the through-hull. Item #5 on the list is to add a vent loop. http://store.hamiltonmarine.com/browse.cfm/vented-loop-1.50-1-1-2-114665-/4,5165.html
These can be found with most suppliers.
All U Get

Jalepeno · Mar 16, 2011

I owned a 1986 h23 for eleven years. The h23 is a flat bottom boat that does not have a real bilge but three 2” deep pans where the keel bolts are located under removable cabin soles. These pans are interconnected with weeping holes to the storage areas under the settees and under the V-berth. They are not connected to the lazarette storage area and water would have to rise well above the sole (~6") to flood into the lazarette. There is no way for water to get into the lazarette unless you have a leaking lower rudder gudgeon, deck fittings and/or hull/deck joint. If your h23 is built the same as mine was, there is also not way for water to make its way from the lazarette into the settee storage areas without first flooding both the pans and cabin sole.

At first, I also had water in the settee storage areas and the pans after rains and/or heavy weather sailing, but using talcum powder and found leaks in the anchor/sail locker drain hose, the trailer eye ring, the starboard dead light (window) and the port side hull/deck joint, and water in the lazarette from a crack in the cockpit drain hose and loose rudder lower gudgeon bolts.

The h23 is dry boat that likes to be sailed flat (max 15 deg of heel) and come from the factory with only a portable manual pump. The storage areas, bilge pans and lazarette were bone dry for the next ten years of ownership after I fixed the leaks. For safety, I installed a Rule 500 gph electric pump with float switch epoxied to a plywood pad at the lowest forward point in the lazarette with the ¾” discharge hose forming a non-vented loop by following the port side bulkhead very high above the battery and water tank to a discharge fitting just below the hull/deck joint and rub rail on the port side just aft of the optional sliding galley sink drain.

You should find and fix the water leaks as soon a possible so you don’t rot the imbedded plywood transom and deck stiffeners.

FastOlson · Mar 17, 2011

Water in, Water Out

Time to take a deep breath and calm down.
*Centrifugal bilge pumps are cheap to make and profitable to install.
And, they allow easy back flooding due to syphoning.
When working perfectly, with no clogging and minimal head, will pump more water per $ invested. This is in a perfect world with smooth-bore hose and short runs. In the other 95% of typical boat installations they fall way short of the advertised GPH water movement. Oh yes, did I mention that they are cheap?
Any sag in the discharge line can combine a section of air and old water and produce an "air lock" that will not allow the pump to start up next time and work properly, also.

*Triple Chamber-type bilge pumps are expensive, and their built in check valves will not allow syphoning. They move less water, but meet their GPH specs more often.

*99.9% of time you want the bilge pumped out it is for removal of small amounts of water from deck leaks or seepage from a poorly-adjusted stuffing box.

Major flooding would lead quickly to small debris jamming that little plastic impeller in your Rule (or other brand) centrifugal pump fairly quickly, unless you are very very lucky.

*In the case of major flooding, your best bet (other than and in addition to quick damage control) is the long handle on the cockpit-mounted Gusher pump that will move a lot of water per stroke. If your boat builder did not install one of these due to marketing to the "thrifty" end of the market, install one yourself.
(Insert old saw about "frightened man with bucket" at this point!)

Regarding dry powder for finding a leak -- a small leak will leave a trail thru a dusting of powder for your "leakage CSI" investigation a day later.

Stay Dry,
L

jibes138 · Mar 17, 2011

I had a similar problem and found the cockpit drain hoses, buried way in the stern behind a bulkhead, had rotted and when heeled would allow some water to come in, so if the boat is several years old check the condition of all hoses in the boat, they are life limited and failure can cause a sinking. Anything older than maybe 10 years you might want to think of replacing, most rubber products have a shelf life and many are 5 years.

Gregor · Jul 5, 2011

I'm a new owner of a 1983 H22. Boat has prob not been in the water for several years. No bilge pump on boat. Bought a 750 gph centrifugal auto pump. Am looking for advice or knowledge on where the pump should discharge the bilge water.
I was pumping it overboard but now am pumping out thru the gallly sink thru hulll. I think I am seeing some siphoning of water back into the bilge once the auto pump shuts down. Any specific advice on how to avoid the siphoning back of water once it's pumped out?
Also, would it be possible to drain the gally sink and the bilge pump out thru the same thru hull (using a tee connector and maybe a check valve)?

Steve Dion · Jul 5, 2011

Kermit:

I would agree with just putting a loop in the line. This is what Hunter has done on many of the boats. I doubt that you boat came with a pump, so who ever did it may not have installed the thru hull high enough either.

thinwater · Jul 5, 2011

Freezing is just one of those ways.

Roger Long said:
DO NOT under any circumstances install it. Bilge line check valves with electric pumps can sink your boat a couple of different ways.

Part way down this post is a nice picture of my neighbor's boat sinking due to a poorly routed bilge pump hose ( a pocket that froze), but a check valve would do the same thing. A diaphragm pump with internal flappers will do the same thing.

http://sail-delmarva.blogspot.com/2009/12/winter-sailing.html

This is probably the most common cause of winter boat sinkings.

Also, most flapper check valves won't function in a down hill leg; they will simply hang open. A spring check would almost certainly foul.