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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

An Automatic Bilge Pump System

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sethp001
Mainsheet C-25 Tech Editor

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814 Posts

Initially Posted - 05/08/2015 : 20:00:04

Hello folks - I want to share what I've decided to implement for my automatic bilge pump system on my swing keel boat, which may benefit someone else. After considering a plethora of possible design options and manufacturers' systems to combine, I think this offers (me) the best value, safety, and ease of installation. Criticisms welcome.

3 Rule LoPro 900 Automatic Bilge Pumps
-1 beneath starboard salon
-1 beneath port salon
-1 beneath vberth
3 1 1/8" y connectors at transom near waterline
2 1 1/8" to 1" adapters for manual bilge pump integration
3 Rule 3-way Illuminated Bilge Pump Switches

Advantages:
1. No new through-holes in transom
2. Triple pump redundancy
3. Triple clogged strainer redundancy
4. Power redundancy (two pumps wired to one battery, one pump wired to the other, and 10A per bank charger can keep up with power draw at the dock)
5. Less water in (my) typical water collection areas
6. Integrated tricuspid values to prevent back flow
7. Integrated switches turn pumps on at 1.3" water level
8. Combined 1900GPH pumping rate (includes calculation for head loss)
9. 1 1/8" to 1" outlet reduction at transom near waterline minimizes additional water head pressure and prevents back flow to manual bilge pump inlet
- The Rule LoPro pumps have a longer warranty than the Whale low profile pumps and cost much less.

Disadvantages:
1. Single point of plumbing failure at existing bilge pump through-hull
2. 9 new plumbing connections (points of failure) near waterline
3. Possible failure of integrated tricuspid valves relegating system ineffective
4. Combined 1900GPH pumping rate when I would prefer 4000GPH
5. Additional water head pressure when all three pumps active due to combining three 1 1/8" outlet pumps to one 1" outlet

Seth
"Outlier" 1987 Catalina 25 SR/SK/Traditional Interior #5541
"Zoo" 1977 Morgan Out Island 30
"Nomad" 1980 Prindle 16
"Lost" 1988 Catalina Capri 14.2 (sold - yay!)
"Marine Tex 1" Unknown Origin POS 8' Fiberglass Dinghy
https://whichsailboat.com/2014/07/27/catalina-25-review/

Edited by - sethp001 on 05/08/2015 20:04:47

islander
Master Marine Consultant

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USA
4018 Posts

Response Posted - 05/10/2015 : 14:06:23

quote:
tricuspid valves

????? I googled this and all I come up with is something to do with your heart. Are they backflow preventers?

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Voyager
Master Marine Consultant

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USA
5352 Posts

Response Posted - 05/10/2015 : 22:52:51

Scott, all that means is that the valve has three triangular flaps that open in one direction (the direction of flow) and close back on themselves preventing back flow. This is exactly the type of valves we have in our hearts.

Edit - that said, Seth it seems like your boat is typically leaking here and there, so the three pump solution can help prevent it getting full of water and potentially sinking!

My question is, where's all the water coming in from? The rain, a crack in the hull, bad through-hull fittings or what???

I've only been on one swing keel C25 before and it too seemed a little soggy down near the ankles! Is this a trend?

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Edited by - Voyager on 05/10/2015 22:59:18

sethp001
Mainsheet C-25 Tech Editor

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814 Posts

Response Posted - 05/14/2015 : 19:50:14

Bruce - The water intrusion is definitely from deck hardware that needs re-bedding. Also, the bilge is dry when there's no rain.

An additional comment on the tricuspid valves - they reportedly reduce flow much less than other back flow preventing valves. After I get everything installed, I will test the system by seeing how fast it can fill a 5 gallon bucket held below the outlet port at the transom. I think I also ought to test the back flow preventing capability by getting two pumps running and seeing if water comes out of the pump that is not running. Since these valves are a type of rubber, I presume they'll need replacing at some regular interval, but I'm not sure what that would be yet.

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 05/17/2015 : 07:59:02

I am sorry your boat leaks.

Frank Hopper

Stinkpotter
Master Marine Consultant

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Djibouti
9076 Posts

Response Posted - 05/17/2015 : 10:19:24

A curmudgeon's reaction: It seems to me, if I understand your description, the single thru-hull is likely to reduce the effectiveness of three pumps running to about that of one of them. Each will create back-pressure against the others and their associated check-valves, especially with the reducer at the combined exit point. And I don't understand how the reducer reduces the head. I believe the larger diameter line running to it increases the head (the weight of the volume of water being lifted.)

All sources I've seen advise strongly against check-valves in bilge pump systems. But that demands that you don't combine multiple pumps to one outlet. This is one place where additional holes in the transom are worthwhile. At the very least, I'd keep the manual pump isolated from the outlet for any automatics.

I'd also re-bed whatever is affecting your V-berth compartment, and also check for leaks around the top of the anchor locker and maybe a clogged drain hole in the bow--then go with the two pumps in the bilge. The one up front seems like overkill to me.

But it's your boat...

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

sethp001
Mainsheet C-25 Tech Editor

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814 Posts

Response Posted - 05/18/2015 : 18:47:28

quote:
Originally posted by Stinkpotter

It seems to me, if I understand your description, the single thru-hull is likely to reduce the effectiveness of three pumps running to about that of one of them.

I calculate the pumping capacity will be reduced to about two of them but I could be wrong.

quote:

Each will create back-pressure against the others and their associated check-valves, especially with the reducer at the combined exit point.

Back pressure to other pumps will be reduced by locating the reducer at the transom, lower in the system after the anti-siphon loops.

quote:

And I don't understand how the reducer reduces the head.

The reducer allows for a larger diameter hose to be used for each run from each pump to the transom. Larger diameter hose reduces friction loss, effectively reducing head.

quote:

I believe the larger diameter line running to it increases the head (the weight of the volume of water being lifted.)

The larger diameter of the line allowing for a larger volume of water to be in the line does not increase head pressure. Hydrostatic pressure is dependent on gravity, the change in elevation, and the density of the fluid, but not the volume of the fluid.

Edited by - sethp001 on 05/18/2015 23:22:46

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