dry bilge system

[Dago]

Hi Everyone,
I recently posted a question about my bilge, and I have a follow-up question.

For those of you with a dry bilge system, where do you route the discharge. I'd like to schedule the dry bilge system to run at regular intervals unattended (I bought a Bilge-B-Dry from Neptunian Sky), so I'd like to route the discharge out of the boat. I typically close my thru hull valves, so I don't want to tap into the galley or head sink drain. The shower pan drain is on a manual switch so that doesn't work. That leaves the discharge hose for the regular high capacity bilge pump. If I tap into that drain, should I be concerned about any discharge flowing back to either of the bilge pumps (either the Bilge-B-Dry's flowing back to the Rule pump, or visa versa)?

I could tap into the discharge hose all the way back at the thru hull after a anti-siphon loop, but it's a long run and I'm not sure the Bilge-B-Dry pump would have trouble with that.

I appreciate and tips and suggestions. Thanks, Dago

[Noah]

In my opinion, I would not spend time, money and energy on trying to have a pump set-up to try and achieve a totally dry bilge. You will always get some back flow. My Rule 2000 pump runs to the transom with a high anti-syphon loop and it back flows a bit. I then mop that little bit out with a sponge and bucket. My concern is why and where your water is coming from that you need to run the pump ofter when you are away from the boat. Unless there is a catastrophic failure, the only place water should be coming in our fiberglas boats is rainwater (with a keel-stepped mast) or through the stuffing box (with a traditional packing gland). Otherwise you have "leaking" issues that need fixing.

[Ron Hill]

Dago : I agree with Noah. I have drip Free packing so it's just rainwater down the mast. I take a sponge and take up any rain that might have come down.

Don't think a "Bilge-B-Dry pump is necessary!!

A few thoughts 

[Dago]

In my opinion, I would not spend time, money and energy on trying to have a pump set-up to try and achieve a totally dry bilge. You will always get some back flow. My Rule 2000 pump runs to the transom with a high anti-syphon loop and it back flows a bit. I then mop that little bit out with a sponge and bucket. My concern is why and where your water is coming from that you need to run the pump ofter when you are away from the boa?. Unless there is a catastrophic failure, the only place water should be coming in in our fiberglas boats is rainwater (with a deck stepped mast) or through the stuffing box (with a traditional packing gland). Otherwise you have "leaking" issues that need fixing.

I agree that the bilge should be relatively dry, and I do have a dripless stuffing box. But it does rain here in the Puget Sound quite a bit, and with a 36 year old boat I imagine there are a number of "little" leaks in various places. Maybe I should see how fast the bilge fills with water in a more quantitative way once I've rehabbed the discharge hose before installing a dry bilge system.

Thanks for your thoughts. Dago.

[Dago]

Dago : I agree with Noah. I have drip Free packing so it's just rainwater down the mast. I take a sponge and take up any rain that might have come down.

Don't think a "Bilge-B-Dry pump is necessary!!

A few thoughts 

Thanks Ron. I think I'll do some more investigation.

[rmjohns]

Dago,
    That looks like an interesting system. The Q&A says they have tested up to an 8 ft lift with 5 below the pump and 3 above. They also said they have tested with 25' of hose before the pump and 25' after, so plenty for our Catalina's. I think I'd look at putting the pump unit under the head sink. The only challenge there might be getting the hose to the bilge under the floorboards. And then I'd discharge out the stern. If your main pump has a vented loop then you should be able to tie in after that, but I think I'd just add another dedicated discharge thru-hull as high up in the stern as you can get it. I didn't see anything in the instructions about needing a vented loop in the discharge, but you might want to consider one.

Rob 

[Dago]

Dago,
    That looks like an interesting system. The Q&A says they have tested up to an 8 ft lift with 5 below the pump and 3 above. They also said they have tested with 25' of hose before the pump and 25' after, so plenty for our Catalina's. I think I'd look at putting the pump unit under the head sink. The only challenge there might be getting the hose to the bilge under the floorboards. And then I'd discharge out the stern. If your main pump has a vented loop then you should be able to tie in after that, but I think I'd just add another dedicated discharge thru-hull as high up in the stern as you can get it. I didn't see anything in the instructions about needing a vented loop in the discharge, but you might want to consider one.

Rob 

I like the idea of putting the pump under the sink in the head. For the discharge hose, I could also tap into one of the hoses for the scuppers in the cockpit, very little chance of back flow there. I'm going to make a better assessment of the rate of water in the bilge and then decide if I'm going to install the system.

Thanks for your thoughts. Dago

[waughoo]

I have purchased one of those dry bilge systems, but not yet installed it.  Due to the length and diameter of the discharge hose, a fair amount of water returns to the bilge.  In my imagined implementation, the dry bilge system does the work of taking care of the general water that accumulates in the bilge from rain water leaks, and the other bilge pump does the evacuation of large volumes of water in the event of a failure.

[Jim Hardesty]

I could also tap into one of the hoses for the scuppers in the cockpit, very little chance of back flow there.

Don't know how safe that would be.  At times when Shamrock, a MKII, is going fast and healed over water has come up from the low side cockpit drain.  Think that only happens on the starboard side, port tack.
Jim

[Dago]

I could also tap into one of the hoses for the scuppers in the cockpit, very little chance of back flow there.

Don't know how safe that would be.  At times when Shamrock, a MKII, is going fast and healed over water has come up from the low side cockpit drain.  Think that only happens on the starboard side, port tack.
Jim

Fair point Jim (although I don't know that I've ever gone that fast). Dago.

[Dago]

I have purchased one of those dry bilge systems, but not yet installed it.  Due to the length and diameter of the discharge hose, a fair amount of water returns to the bilge.  In my imagined implementation, the dry bilge system does the work of taking care of the general water that accumulates in the bilge from rain water leaks, and the other bilge pump does the evacuation of large volumes of water in the event of a failure.

I agree Alex. I'm worried about the water flowing back and defeating the purpose for this second, low capacity pump to remove the residual water. That's why I'd like to keep the discharge hose as short as possible, and am thinking about where to discharge. If I do install the system, I may just collect the discharge in a small tank until I get a better idea of the volume and figure out where to discharge.

Is there any particular reason you haven't installed your system yet? Second thoughts?

Thanks for your input. Dago.

[waughoo]

Dago,

The dry bilge system uses a pump that by nature doesn't flow backwards.  Thus, the issue of back flow filling the bilge is not an issue with the neptunian sky system.  If you really wanted to make sure... a vented loop could be installed, but I don't plan to do one on my system.

As for why it isn't installed yet, it is MUCH easier to buy new toys for the boat than it is to clear the schedule to get them installed :-)  I have some more open time this winter and it is on the list to get it done.  However, we shall see.

[Dago]

Dago,

The dry bilge system uses a pump that by nature doesn't flow backwards.  Thus, the issue of back flow filling the bilge is not an issue with the neptunian sky system.  If you really wanted to make sure... a vented loop could be installed, but I don't plan to do one on my system.

As for why it isn't installed yet, it is MUCH easier to buy new toys for the boat than it is to clear the schedule to get them installed :-)  I have some more open time this winter and it is on the list to get it done.  However, we shall see.

I sympathize, good luck finding the time.

[waughoo]

Dago,

Please report back when you install yours.  I would be very interested to see someone else's installation.  In the PNW, I feel a dry bilge system would significantly help with boat funk odors.