Bilge hose - important difference!

[rhody98]

And the head difference matters too - height from pump to discharge. I dont know your setup Father, but the relative elevation of the pump and the water levels in the two tanks will impact the results. I would expect you would get higher flow rates if the 600 gal tank is topped off versus the water level just above the pumps with a garden hose keeping the water level static. So your results for both hoses are probably even better than actual conditions in a boat where the lift is, say 18" (2'?).

I came across results from pump tests Rule financed in 1997, all with a 3' head (lift).
Attwood 500, smooth hose = 302 gph, corrugated hose = 242 gph.
Rule 1100, smooth hose = 682 gph, corrugated =530 gph.
Rule 2000, smooth hose =1,052 gph, corrugated = 880 gph.

So in a boat where a bilge pump is lifting water 18" (or whatever), can we guess that actual results may be somewhere between Fthr Franks #'s and the Rule test #'s? In any case it should be apparent that pumping at the manufact. rated output is unlikely to happen.

Also, interesting to compare these to flooding rates: a hole 1 ft below waterline, 1" in dia. lets in 20 gpm - that's gal per minute which is 1,200 gph! A 2" hole 1' below the waterline is 79 gpm, or 4,740 gph. I will stop now before I convince myself not to launch this Spring...

I should list my source, its a book my wife got me for Christmas, Boatowner's Mech and Elec Manual.....spent more time with it than the socks.