dry bilge system

[Noah]

The backflow will generally be the amount of water left in the hose, between the pump and the anti-syphon loop.

[waughoo]

So the main centrifugal pumps often found as bilge pumps can pump a lot of water fast and often have a moderatly sized discharge hose.  That is the pump that will drain a fair amount of water back into the bilge after the float switch turns it off.  Many people install a check valve to help with that.  However, if the pump sucks air and looses its prime, that check valve will not allow the pump to evacuate water the next time.  So, I plan to use the neptunian bilge be dry system to evacuate the nuisance water and let the centrufugal pump do only the heavy lifting for say when I wash the bilge, spill a fresh water tank into the bilge or have an emergency situation.  The neptunian system doesn't back flow as the pump is a system of check valves so there is no run back when the pump turns off.

[Noah]

Alex— do I understand correctly that you are saying with the Bilge-B-Dry pump there is a check valve in their pump, so that that any water left in the long hose run (that does not get pump out past an anti-syphon loop) remains in the hose—as opposed to emptying back into the bilge?

[waughoo]

Noah,

Yes... however it is not a separate check valve, it is just the design of the pump.  It is similar to the diaphram pump for the shower drain that has one way check valves built into the pump body so the pump can suction and then pump with the same diaphragm.

[Dago]

So the main centrifugal pumps often found as bilge pumps can pump a lot of water fast and often have a moderatly sized discharge hose.  That is the pump that will drain a fair amount of water back into the bilge after the float switch turns it off.  Many people install a check valve to help with that.  However, if the pump sucks air and looses its prime, that check valve will not allow the pump to evacuate water the next time.  So, I plan to use the neptunian bilge be dry system to evacuate the nuisance water and let the centrufugal pump do only the heavy lifting for say when I wash the bilge, spill a fresh water tank into the bilge or have an emergency situation.  The neptunian system doesn't back flow as the pump is a system of check valves so there is no run back when the pump turns off.

I think I'm getting it now. I don't need to worry about the water in the discharge hose from the Bilge-B-Dry flowing back, but if I do tap into the discharge hose of the Rule I have to do it after the anti-siphon loop, otherwise that water will flow back into the bilge by way of the Rule's discharge hose. Or have a dedicated thru hull for the Bilge-B-Dry as you mentioned.

Thanks for all of your information Alex, I appreciate it. I'll be sure to let you know how the installation went. Dago