Bilge Pump Discharge Hose

[tomschauer]

Source of the post You stated earlier that you were contemplating routing the bilge water to the grey water tank. That implies that you can access the grey water tank. If you can access the outlet hose to the thru hull, you can install a check valve after the grey water pump and Tee the bilge pump hose into the grey water hose maybe. On the 506 that I'm buying I noticed that none of the bilge pump hoses are equipped with check valves so when the pumps stop then the water in the hose just flows back into the bulge. I will be installing check valves a few inches down stream of each pump to keep that water from reentering the bilge.

There will not and should not be check valves in the bilge pump discharge lines. They restrict flow (raise head pressure) and offer the chance of failure and clogging. There is a loop on the discharge line that rises above the thru hull. This acts as an anti siphon and prevents water from coming in through the thru hull.

[bud37]

I agree with Tom.......Just to add...., bilge pumps that are centrifugal/vane style pumps will not do well against a closed check valve which has held a line full of water which the pump may not overcome.....just spins and heats up.....can depend on the quality of the pump design.....not worth the chance.

[Viper]

Ya I wouldn't be putting any check valve in a bilge pump discharge. Check valves can fail in the closed position, you don't want that happening in an emergency when you need the pump water overboard.

[Carpediem]

Good points guys, Maybe Ill just put together a dry bilge system to evacuate the water that doesn't discharge over board then. I really abhor water standing in my bilge.

[tomschauer]

I use a little 2.5 gallon shop vac to clean up whatever the pumps won't remove. It actually gets stored in the galley bilge. Usually only need it after commissioning in the spring, mid season when I rinse the bilges, and during winterization.
I don't like water in there either.

[km1125]

Did you determine how water was getting in there in the first place?

Seems like there are two issues. One is how water is getting in there and collecting, and the other is fixing the bilge pump hose somehow to evacuate whatever water does get in there, at least down to a reasonable level. If you want to go completely dry, then you still need a 'dry bilge' system or use the shopvac approach.

[g36]

this pump removes almost all water you could add this to remove what the other pumps may leave and reduce the amount left .https://www.whalepumps.com/marine/produ ... ilge-Pumps

[Carpediem]

Source of the post Good points guys, Maybe Ill just put together a dry bilge system to evacuate the water that doesn't discharge over board then. I really abhor water standing in my bilge.

Upon thinking about your responses, I'm calling bull shit guys. There is absolutely nothing wrong with putting a duck bill style check valve in the discharge lines. Why would you not want to evacuate all the water from your bilge? Im just now buying my first Carver after owning 6 boats over 28 years from 18 foot run about to 44 foot flybridge sport yachts. My RInkers and Sea Rays had check valves in every bilge pump discharge line and I never experienced a failure. My bilges were always dry and clean as a whistle. The 506 I'm buying has, by design, no way to evacuate all the water from the bulge and as such is filthy, grimy, slimey and stinky. Ok for a crab boat but not a luxury sport yacht. I stand by my advice to the OP as a good solution to his problem and take issue with you guys that are okay with standing swamp water in your boat. To each his own though.

[tomschauer]

https://www.wholesalemarine.com/content ... Manual.pdf

Here's a rule manual. It clearly states "no check valve"
It also shows the flow rate at various ft of head pressure. The flow is rated at zero ft of head. Not sure what a duck bill would add, but bet it cuts the flow at least in half.

[km1125]

Source of the post

Source of the post Good points guys, Maybe Ill just put together a dry bilge system to evacuate the water that doesn't discharge over board then. I really abhor water standing in my bilge.

Upon thinking about your responses, I'm calling bull shit guys. There is absolutely nothing wrong with putting a duck bill style check valve in the discharge lines. Why would you not want to evacuate all the water from your bilge? Im just now buying my first Carver after owning 6 boats over 28 years from 18 foot run about to 44 foot flybridge sport yachts. My RInkers and Sea Rays had check valves in every bilge pump discharge line and I never experienced a failure. My bilges were always dry and clean as a whistle. The 506 I'm buying has, by design, no way to evacuate all the water from the bulge and as such is filthy, grimy, slimey and stinky. Ok for a crab boat but not a luxury sport yacht. I stand by my advice to the OP as a good solution to his problem and take issue with you guys that are okay with standing swamp water in your boat. To each his own though.

It all depends on the bilge pump. Some displacement pumps do have check valves built right into them but on centrifugal pumps any resistance in the output line can lead to an 'airlock' where the pump can't develop any pressure at all because the impeller is spinning in mostly air. Centrifugal bilge pumps don't develop much pressure at all when running, which is also why even a slight restriction in their output hoses will drastically reduce their performance when you need them most.

I don't think anyone is advocating for water standing in the bilge, but some of us have been used to dealing with it due to conventional packings that have been around forever.

It's also a case of using "the right tool for the job". Relying on your emergency bilge pump to result in a dry bilge is the wrong goal. You want your emergency bilge pumps ready and optimized to do what they are supposed to do - quickly purge as much water out of the bilge as possible. If you truly want a dry bilge, install something specifically for that purpose. Could just be a small bilge pump or could be one of the more advanced "dry bilge" systems. There are a few DIY systems that just use a small potable water pump to 'vacuum' the bilge and you just put it on a timer.