Bilge Pump Comparison Rule vs Jabsco

Oct 29, 2016
1,929
Hunter 41 DS Port Huron
My current main bilge pump is a Rule 1500 which claims to pump 1500 gallon per hour at an open flow rate, put a resistance of 7 ft of head against the pump (lift plus line resistance) and it drops down to 650 gph or about 10 GPM.
I am considering changing this pump to a Jabsco 36680 (5.5 GPM ) while I can not find any efficiency curves for this pump my experience tells me that a diaphragm pump will pump the stated volume as it is works on the displacement principal as long as the resistance is within reasonable consideration.
The reason for the change is to allow bilge water to be pumped out with no run back as what happens when the current Rule pump completes a cycle, half the water pumped out returns from the discharge hose through the pump. Its not recommended to install a check-valve on the discharge I imagine for a couple of reasons, 1- Added flow restriction, 2- Increased risk of flow failure due to valve not opening against the head resistance of the trapped liquid.
My question being, will the reduced amount of the flow provided by the Jabsco be an issue? My initial thought is not at all, but I thought I would seek the advice from the great many of sailors here who I am sure have pondered this type of question.
I like the Jabsco as it appears that the pump is able to be rebuilt instead of chuck and replace, I would like to stay with this model as it matches the existing wire and breaker sizes.
 
Last edited:
Feb 6, 1998
11,701
Canadian Sailcraft 36T Casco Bay, ME
My current main bilge pump is a Rule 1500 which claims to pump 1500 gallon per hour at an open flow rate, put a resistance of 7 ft of head against the pump (lift plus line resistance) and it drops down to 650 gph or about 10 GPM.
I am considering changing this pump to a Jabsco 36680 (5.5 GPM ) while I can not find any efficiency curves for this pump my experience tells me that a diaphragm pump will pump the stated volume as it is works on the displacement principal as long as the resistance is within reasonable consideration.
The reason for the change is to allow bilge water to be pumped out with no run back as what happens when the current Rule pump completes a cycle, half the water pumped out returns from the discharge hose through the pump. Its not recommended to install a check-valve on the discharge I imagine for a couple of reasons, 1- Added flow restriction, 2- Increased risk of flow failure due to valve not opening against the head resistance of the trapped liquid.
My question being, will the reduced amount of the flow provided by the Jabsco be an issue? My initial thought is not at all, but I thought I would seek the advice from the great many of sailors here who I am sure have pondered this type of question.
I like the Jabsco as it appears that the pump is able to be rebuilt instead of chuck and replace, I would like to stay with this model as it matches the existing wire and breaker sizes.

One or two LARGE (biggest that will fit) centrifugal "oh-$hit pumps", a small "diaphragm-type" nuisance water pump and a manual "gusher type" makes for a well designed system.

This is not a question of one or the other, the question is really answered as both....

There is also battery voltage, hose lengths and type as well as height and fittings that all reduce "pump ratings".

Centrifugal pump only systems are simply a poor design, but many builders are cheap and most boaters don't really care until it's too late...
 
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Jun 10, 2017
174
Catalina 1980 Catalina 30 Mk II John's Pass / Tampa Bay
Day,

I liked what Main had to offer.

Personally, I am not a fan of Jabsco products, the last one was from 10 years ago.
Having a C30 with a small bilge, I decided to do some checking.
What I found, was that the smaller the bilge, the larger the pump you should have.
This makes sense.

I also found problems with pumps that had an internal float switch.
If the float has crap on it, it may change the dynamics.

I changed to a Rule 5000 pump & I use a separate float switch.
This has worked great for me. Also as for wiring, I have my wire connections
set up high so water will not compromise the connectors and,
they are wired to a fused panel connector board.

I haven't had a problem in years & sometimes, I fill the bilge & hit my manual switch just
to check & ensure proper draining. My bilge drains quickly & stays mostly dry except for a
maybe a half inch of standing water that the float switch doesn't register.

It is also a good idea for pump & float to be in the lowest part of your bilge.
 
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nat55

.
Feb 11, 2017
210
Gulfstar 1979 Gulfstar 37 BELFAST
Oct 29, 2016
1,929
Hunter 41 DS Port Huron
One or two LARGE (biggest that will fit) centrifugal "oh-$hit pumps", a small "diaphragm-type" nuisance water pump and a manual "gusher type" makes for a well designed system.

This is not a question of one or the other, the question is really answered as both....

There is also battery voltage, hose lengths and type as well as height and fittings that all reduce "pump ratings".

Centrifugal pump only systems are simply a poor design, but many builders are cheap and most boaters don't really care until it's too late...
@Maine Sail, Thanks for the response, you have cleared up a secondary thought that I had and this is, why not leave the Rule 1500 in, but set to a higher trip point. I have a high water pump which is a Rule 2000 and I will add a circuit to cover what you refer to as a nuisance water pump. One can not have enough pump capacity when its really needed, is the point you are making, I get that.
I do understand the whole voltage to performance relationship as well as voltage drop to wire size and length, thanks again for your input.
 

capta

.
Jun 4, 2009
4,905
Pearson 530 Admiralty Bay, Bequia SVG
One negative point w/the Jabsco pumps. It only takes a human hair in either diaphragm to stop the pump working. It will also be necessary to have at least several spare diaphragms around as they do fail.
All that said, we have the biggest Jabsco diaphragm (don't remember the number) as our main pump and a Rule 3500 as a secondary above it. However, even with both of them running, that really isn't much pumping capacity.
For that, we carry 4 of these; 1/2 HP Non-Clogging Vortex, Reinforced Thermoplastic Submersible Utility Pump, which we can operate off the generator or the inverter, should the need arise.
wayne-submersible-utility-pumps-vip50-64_1000.jpg
 
Jun 10, 2017
174
Catalina 1980 Catalina 30 Mk II John's Pass / Tampa Bay
Capta,

I don't know if you are in fresh or salt water however, I think
saltwater causes more growth buildup.

If you feel you are not getting enough pump outflow, I would look at
any valves & hose runs to be sure these are not adding to your problems.
I have no idea what your hose head rise is, I'm guessing about 4 feet but,
look & make sure there is not a potential problem.

I always advise folks to get the biggest pump that will fit.

That's why I went with the 5,000. When installed, there was no problems henceforth.
And, I always look at my stern discharge flow making sure it is unencumbered in flow.
If you have an internal float, get away from it......period. How does one check &
clean an internal float to assure proper activation & drainage??? I could care less.
Been there, done that.
 
Oct 29, 2016
1,929
Hunter 41 DS Port Huron
@capta , I don't believe that I have any flow issues, I did ditch the internal switch and replaced the exiting main bilge pump setup with an independent switch and pump, what I am thinking is, a diaphragm pump will not flow backwards and needs no check valve, so when the nuisance water is pumped out, all of it is either pumped out or will remain in the discharge until the next pumping cycle, thus reducing the amount of overall water residing in the bilge.
But what I have read by creating this post, a diaphragm pump is sensitive to debris, even as unintrusive as a couple hairs, not at all what I would want to do, if that is the case. I can imagine that the pump would not prime given leak-by and fail to work at all when needed.
So like many other questions, the answers are never simple and never does 1 size fit all.
 

capta

.
Jun 4, 2009
4,905
Pearson 530 Admiralty Bay, Bequia SVG
Capta,

I don't know if you are in fresh or salt water however, I think
saltwater causes more growth buildup.

If you feel you are not getting enough pump outflow, I would look at
any valves & hose runs to be sure these are not adding to your problems.
I have no idea what your hose head rise is, I'm guessing about 4 feet but,
look & make sure there is not a potential problem.

I always advise folks to get the biggest pump that will fit.

That's why I went with the 5,000. When installed, there was no problems henceforth.
And, I always look at my stern discharge flow making sure it is unencumbered in flow.
If you have an internal float, get away from it......period. How does one check &
clean an internal float to assure proper activation & drainage??? I could care less.
Been there, done that.
I'm not having "flow issues", well, not with my bilge pumps, anyway. lol
I read THIS;
flooding flow rate.PNG

I have 6, 2" cockpit drains that exit the hull @ 4'. A 2½" engine intake that is also about 4' down, as well as a generator intake and numerous intake thruhulls. This gives me an added 10,000 gph @ 0' head. What have I got to lose?
I don't think any of us have the necessary pumping capacity if we are holed by a log or whatever, without some sort of auxiliary pumping capacity. So, I bought 4 cheap pumps that might just give me time to do something about a hole that might happen.
Plus, they are great for anchor chain wash down, washing the decks, dink and numerous other things.

 
Jun 10, 2017
174
Catalina 1980 Catalina 30 Mk II John's Pass / Tampa Bay
Cap,

On the other hand, I installed a fixed hand pump just incase
of flooding disasters which when checked, is
a great backup if stuck in the cockpit while trying to keep my boat afloat..

Thus, I will no longer forward advice.
 

capta

.
Jun 4, 2009
4,905
Pearson 530 Admiralty Bay, Bequia SVG
Cap,

On the other hand, I installed a fixed hand pump just incase
of flooding disasters which when checked, is
a great backup if stuck in the cockpit while trying to keep my boat afloat..

Thus, I will no longer forward advice.
Yep, the boat came with the larger Edson manual pump too, but at a gallon a stroke, I doubt I could keep up with a serious ingress of water, and deal with the problem at the same time.
I remember reading about the last hours of the Bounty, and wondered if they had had they any means of dealing with the ingress of water, even just slowing it significantly, whether if it might have made a difference?
On the old, aluminum SWATH treasure hunting vessel operated in the T&C, we had weekly drills, making sure the gas powered pumps were working properly and that every crew member, even the cook, could operate every one of them 'with their eyes closed'.
I put bilge pumps right after anchor tackle, when considering vessel safety and security.
 
Jun 10, 2017
174
Catalina 1980 Catalina 30 Mk II John's Pass / Tampa Bay
Cap,
The Bounty was NEVER SEAWORTHY when it left port.
This has been documented & the bottom line was $$$.
Then this ******* captain thought he could skirt between the hurricane & the Florida coast.
Well, we all know how that turned out.

I don't mind since he was an ******* that he perished but, a first time female crewmember that
trusted him also perished. And in better times, I also once took a tour of the replica Bounty.

This however is an isolated story of bad & POOR decision making.

What we as small boat owners may endure can be different. I am only saying that,
having the right size/type pump & proper drainage can make all the difference in survival.

I only speak from experience but at this juncture, I'm outta here..................
 
Feb 6, 1998
11,701
Canadian Sailcraft 36T Casco Bay, ME
These look like a Chinese made version of the Rule pumps, the specs verbiage indicates that a translator was used "Produced by the sophisticated technology" and "You should change it on a regular basis
Reasonable price, brings you the best usage experience". It also indicates 12 volt but the image indicates 24 volt.
Rule Chinese knock-offs and outright counterfeit Rule pumps are inthe US market. If you think the genuine Rule pumps have poor reliability, and believe it or not, the Rule's are better than most others in this regard, the Chinese knock-offs are worth less than the card board they used to ship them in.
 

capta

.
Jun 4, 2009
4,905
Pearson 530 Admiralty Bay, Bequia SVG
Cap,
The Bounty was NEVER SEAWORTHY when it left port.
This has been documented & the bottom line was $$$.
Then this ******* captain thought he could skirt between the hurricane & the Florida coast.
Well, we all know how that turned out.

I don't mind since he was an ******* that he perished but, a first time female crewmember that
trusted him also perished. And in better times, I also once took a tour of the replica Bounty.

This however is an isolated story of bad & POOR decision making.

What we as small boat owners may endure can be different. I am only saying that,
having the right size/type pump & proper drainage can make all the difference in survival.

I only speak from experience but at this juncture, I'm outta here..................
A very, very interesting and telling post.
I'm not sure how you came by your assessment of Capt. Robin Walbridge, but many captains, including Captain Jan Miles of the Pride of Baltimore, who I believe is rather well respected in the tall ship community, was a friend of and had respect and admiration for Capt. Robin Walbridge. Doing the difficult and nearly impossible job of keeping the Bounty operating for so many years on a shoestring budget, he managed to make that vessel available to thousands like yourself who would never have had the opportunity to get aboard her, had he not.
In discussing the incident with Jan, he could not understand what had led Capt. Robin Walbridge to make the decisions that led to the tragedy, but he felt it was out of character and was deeply saddened by the loss of a friend.
So, I'm wondering at your experiences versus those of distinguished captains such as Captain Jan Miles, that would make you label Capt. Robin Walbridge with so many asterisks.
 
Jun 10, 2017
174
Catalina 1980 Catalina 30 Mk II John's Pass / Tampa Bay
Capta,

You don't have the full version of what & how it happened pal.
Do some in-depth searches & you will see that not only the owners, nor the inoperable bilge pumps,
plus a dumb deathly decision to sail an unseaworthy poor conditioned boat hoping to beat a hurricane....REALLY?

Oh, and she needed to be at port in Tampa Bay by such-n-such date.....is what proved deadly.
But, so few boatowners know the real circumstances surrounding the sinking & loss of life.

The biggest Bounty problem was that bilge pumps that were NOT working.
And, let us not forget the leaking water coming in thru the hull slats.
This has been documented & recorded.
So, now how is your bilge pump working, any problems...............?