Any ideas how long of a run you can make with a 500 & 1000 bilge pump, manufacturer just says short as possible, I would like to run them about 10 ft
Length of bildge pump run
- Thread starter sailnewbie
- Start date
I am running smooth wall, so I'm good on that. Anyone ever put a check valve in to keep that 10' of water from running back
It might, my plan is for the 500 to only do clean up work, I built a floor over my bilge area to keep feet dry and the 1000 is if needed only
Head is the vertical distance between pump and discharge, not length of hose. A Mac may have what, 3 feet of head?
No check valve. Deal with water in the hose by installing solid-state pump switch that has an over-run feature, and use a modest hose diameter to manage volume.
No check valve. Deal with water in the hose by installing solid-state pump switch that has an over-run feature, and use a modest hose diameter to manage volume.
I just finished installing a bilge pump in my boat, I was not aware of switch that had a over run feature, live and learn
Hmm have to look into that, my name is newbie for a reason, prior to this has been a aluminum deep vee fishing boat, batterys nor bilge really mattered
I tried it in a bucket first and held the hose up 5' or so and it pump fine over a 12' length, not a super jet stream by no means but pumped a gallon out pretty fast
Well, pump head is elevation and friction loss. Friction Head is the "pack pressure" caused the pump flow and varies with flow rate, pipe diameter, inside smoothness and fittings (like elbow, valves etc). Elevation is a constant, assuming the same liquid properties. Fresh water has less elevation head than salt water.
Time the filling of a gallon container and you get a good idea of the installed pump rate.
Back flow volume is minor and a good thing, to back flush the pump input strainer. Check valves are notorious for failing and reduce the pump flow by additional friction head loss.
Jim...
PS: I am slowly working on "bilge pump" sizing "made easy" post for the forum. My hold up is the "K" friction factors for standard fittings are not readily available.
I would not attempt the check valve. I had a shower bilge assembly that included one and the pump failed to overcome the check valve that the assembly was designed with. I replaced the pump and the check valve with the same results. Called the manufacturer who said he would send me a "matched pair" pump and check valve that he himself would test. Never received the promised "matched pair". In my opinion, this type pump should not be used with a check valve. If the pump is unable to overcome the check valve you will discover a dead battery when you return to your boat.
Bilge pump discharges are rated purely in static head - the height of water column from the pump to the discharge point. Manufacturers cannot know what kind of Rube Goldberg mix of discharge pipe, fittings and constrictive through-hulls you will install but you can assure yourself that all those items will reduce the stated discharge rate. So while you may optimize the flow rate by using large ID smooth discharge hose with easy bends and few fittings; the reality will be that a smaller ID hose will minimize the amount of bilge water that drains back into your bilge.
@Gunni LOL I think we are describing the same "elephant" from different ends.
This link is discussion on Bilge pump capacity and sizing.
http://forums.sailboatowners.com/index.php?threads/dual-bilge-pumps.175414/page-2
On my post #23 on that link, I show the Rube GOLDberg curve in GOLD on a typical Rule® pump curve (ALL pump curves are static head versus flow rate). To determine the pumping capacity of your system, you need to know the Rube Goldberg factors (both static and friction energy loss). As @Maine Sail noted that he thought the manufactures were near criminal since they misled most as to real dependable bilge pump capacity.
@sailnewbie the easiest way to know your GOLD curve, is the "timed" flow rate test of approximate flows with a bit longer hose at the approximate elevation of the proposed discharge point then take about 20% off that flow, to allow for other Goldberg friction.
Jim...
PS: Rube Goldberg was a misunderstood inventor/engineer.
This link is discussion on Bilge pump capacity and sizing.
http://forums.sailboatowners.com/index.php?threads/dual-bilge-pumps.175414/page-2
On my post #23 on that link, I show the Rube GOLDberg curve in GOLD on a typical Rule® pump curve (ALL pump curves are static head versus flow rate). To determine the pumping capacity of your system, you need to know the Rube Goldberg factors (both static and friction energy loss). As @Maine Sail noted that he thought the manufactures were near criminal since they misled most as to real dependable bilge pump capacity.
@sailnewbie the easiest way to know your GOLD curve, is the "timed" flow rate test of approximate flows with a bit longer hose at the approximate elevation of the proposed discharge point then take about 20% off that flow, to allow for other Goldberg friction.
Jim...
PS: Rube Goldberg was a misunderstood inventor/engineer.
The easy solution is to raise the water above the discharge thru hull height as close to the pump as possible. From that point the water will travel via gravity to the discharge and ten feet or more it will drain naturally. The only issue at that point will be how high you have to lift the water at the pump discharge and this is where the "head" calculation is relevant. The higher you try to lift it the lower the volume pumped per unit of time so lift it only high enough to be sure the discharge is below it in all sea state conditions. Finally, the volume of water from pump discharge to the U in the hose will determine if you need to put a check valve inline. It makes no sense to pump the water only to have it siphon back and start the pump again. Put it at a convenient point of access after the pump discharge so you can maintain it---you will need to maintain it (the voice of experience).
My boat had a 1500 BP with about 15' of. 1 1/2" hose, and nowhere to put a "U" rise close to the pump. The hose held about 3 gallons of water and when the pumped stopped it would flow back to the bilge, restarting the pump. Stupid thing would pump the same 3 gallons back and forth all day long. Can't believe the PO put up with that. I fixed it by putting in a small pump with it's own switch and the shortest smallest hose possible. It only holds a few ounces and doesn't restart the pump. I mounted the big pump's switch about 3" higher and it hasn't come on since, and won't unless there is a serious leak.