second bilge pump

[sford1952]

Ahoy, I would like to hear your opinions on where I might install a second back up bilge pump and wiring options on my CHB 35. We love our trawler and want to protect her. Thanking you in advance for a great forum. Steve and Alexa Ford. Oceanside Ca. 760.207-5572

 

[Simi 60]

A few inches higher than the lowest.
But why limit yourself to two?

 

[kapnd]

A few inches higher than the lowest.

Why?
I can see mounting the float switch a little higher on a backup pump, but wouldn’t you want to pump the bilge water down as low as possible?

 

[Bacchus]

My Mainship has 4 bilge pumps in various compartments and a LARGE High Water pump/ float mounted on an alum angle in the lowest compartment.
It is an Emergency high water pump meant to handle real emergency situations where smaller pumps are not handling the flow.

 

[jleonard]

Why?
I can see mounting the float switch a little higher on a backup pump, but wouldn’t you want to pump the bilge water down as low as possible?

Yes this is what I did. 2 pumps.
The "3rd" pump was the shower sump, if it ever got that high.
2 bilge pumps were enough to satisfy my risk analysis.

There was a built in manual diaphram pump that I tried once and it functioned.
But seriously, rather than use that manual pump I would rather have spent my time launching the dinghy.

 

[Gdavid]

It is a good idea, certainly better than one. Depending on the size, age and condition of your current bilge pump you may want to the new unit to be larger, smaller or start fresh with two new units.

Depending on how your boat is currently set up should drive some of your decision making, specifically if you have a small volume of water coming in on a regular and expected basis due to traditional prop shaft packing glands, the condensate from air conditioning or in some cases even the shower, a smaller pump down low set up to handle this regularly accumulating water is smart, a small pump will handle these needs fine and with a smaller diameter hose, you get less water running back in when the pump turns off. Then have your primary pump and it's float switch a bit higher such that it is only operating under unusual situations. The smaller pump will be more likely to encounter the dirt and debris that always finds its way to the bilge while the larger pump is more likely to run nothing but clean water. This isn't to say that you shouldn't be keeping your bilge clean of dirt but setting your system up in this way makes it a little more forgiving.

If you have dripless packing gland(s), your AC condensate plumbed overboard or to the shower sump and your bilge is normally bone dry, having equally sized pumps at the same level would make more sense.

 

[Bill V]

I have 4 bilge pumps. Boat came from factory with 1 electric 1000 GPH pump and a manual pump in aft engine room compartment. When I repowered with new engines in 2006 I installed a new bow compartment 1500 GPH pump, 2 new 2500 GPH pumps in engine room and a new 1000 GPH in engine room. The 1000 is the primary pump and the two 2500's are secondary pumps. All pumps are mounted at same lowest level possible and only the floats are mounted at different levels. Hand/Off/Auto controls for the 4 pumps are all at same location in cockpit. If the low level ER pump runs, no alarm but a red light comes on at the switch and the helm. If the mid level or high level pump runs I get an alarm that wakes up the dead in the cabin and turns on an alarm at the helm station. The manual pump went to the garbage dump. I test run each pump as part of my "pre-checks" before getting underway. I travel in areas that are remote and as far as 60 miles from shore so the ability to stay afloat is very high priority to me. My engine raw water pumps can be used as bilge pumps with the opening and closing of valves as well.

 

[Marco Flamingo]

One of the potential shortcomings of second and third bilge pumps is that they are in the bilge. Look at a pictures of grounded trawlers that leaned over and then flooded on a rising tide. Even multiple million gph bilge pumps can't save them because the flooding is off to one side. By the time water reaches the level of the pump, it's too late. Better a portable 2nd or 3rd pump (ala the pump in bucket in an old thread) or a pump that has an intake hose that can be directed to a particular area or locker.

I don't have that system. My 3rd is manual and I'm well aware of the limitations. I did install a flashing buzzer on my primary pump. It goes off when I test the pump before engine startup as per my checklist. I also removed the original Y and check valve that allowed the shower to use the same through hull fitting as the forward pump and upgraded to smooth-wall hose. That more than doubled the efficiency. I now shoot water out against my neighbor's hull (when he isn't there).

 

[SteveK]

I have two plus shower. Compartments have reduced flow between them thus the reason for more than one pump IMO.
Continuous operation is limited to source of power. There is a limit on the number of pumps when solely running off battery. If the engine is running, as mentioned then a valve switching from raw water intake to bilge draw can work if monitored and not run dry. There are also shaft takeoff pumps. Here is a link that will help decide how many pumps.
Flooding.html

 

[Simi 60]

Why?
I can see mounting the float switch a little higher on a backup pump, but wouldn’t you want to pump the bilge water down as low as possible?

And that's what the first one does
I dont want 2 and double the power draw kicking on at the same time if not needed.

 

[oscar]

a LARGE High Water pump/ float mounted on an alum angle in the lowest compartment.

Got a make/model?

4 bilge pumps in various sections of the bilge taking care of THAT section. Eventually they overflow into the other ones if the water gets high enough. There are 4 high water alarms too. There's always a chance one of them will work........

 

[Marco Flamingo]

I have two plus shower. Compartments have reduced flow between them thus the reason for more than one pump IMO.
Continuous operation is limited to source of power. There is a limit on the number of pumps when solely running off battery. If the engine is running, as mentioned then a valve switching from raw water intake to bilge draw can work if monitored and not run dry. There are also shaft takeoff pumps. Here is a link that will help decide how many pumps.
Flooding.html

Point #3 in the link is where I'm now concentrating. The psi of a leak 18" below waterline is surprisingly low. Sometimes goofy MacGyver emergency repairs (a wetsuit jammed into place with an ice chest) can reduce flow to the point where a bilge pump actually keeps up. There are off-the-shelf hole plugging gadgets and goops, but not necessarily more effective than DIY stuff. Probably the best insurance is to thorougly know how to access all areas.

 

[psneeld]

Damage control is the real success in balancing pumping capacity with reality.

 

[sean9c]

Sort of startling that a 35ft boat would only have one bilge pump. I'd not be surprised to find that it's a small one at that. I guess the assumption is that you'll never need it.

 

[kapnd]

And that's what the first one does
I dont want 2 and double the power draw kicking on at the same time if not needed.

Read that again!
I’m advocating mounting Both pumps as low in the bilge as possible, but putting the float switch for the secondary a few inches higher.
If the primary pump fails, the secondary pump will kick in when the water level triggers it, and it’s audible alarm.
You’ll have to use the manual switch to pump the bilge clear down.

 

[rslifkin]

Read that again!
I’m advocating mounting Both pumps as low in the bilge as possible, but putting the float switch for the secondary a few inches higher.
If the primary pump fails, the secondary pump will kick in when the water level triggers it, and it’s audible alarm.
You’ll have to use the manual switch to pump the bilge clear down.

The downside is that debris can easily clog both pumps at the same time. Different mounting heights reduces that risk and can keep the backup pump dry, leading to a longer life when it's just sitting there for the most part.

 

[AlanT]

The downside is that debris can easily clog both pumps at the same time. Different mounting heights reduces that risk and can keep the backup pump dry, leading to a longer life when it's just sitting there for the most part.

Agree. The other downside is that depending on how and whether you are alerted to a bilge pump activating (light, buzzer or nothing) you may go for years with a failed pump without noticing it. If one pump is mounted higher than the other it is easy to visually determine that the lower pump is/is not working.

~Alan

 

[Bacchus]

Got a make/model?

4 bilge pumps in various sections of the bilge taking care of THAT section. Eventually they overflow into the other ones if the water gets high enough. There are 4 high water alarms too. There's always a chance one of them will work........

I believe mine is a Rule 3700
https://www.walmart.com/ip/RULE-14-...uCc-AjHEHENelIbzKlRoCSPIQAvD_BwE&gclsrc=aw.ds

So advocate mounting LOW with float higher but that doesn't clear the low water as the switch shuts it down.
Better to mount both a little higher and keep both clean and dry normally so they have a higher likelihood of working when needed.

 

[Bacchus]

Read that again!

I’m advocating mounting Both pumps as low in the bilge as possible, but putting the float switch for the secondary a few inches higher.

If the primary pump fails, the secondary pump will kick in when the water level triggers it, and it’s audible alarm.

You’ll have to use the manual switch to pump the bilge clear down.

That doesn't make sense as the higher sw will shut down the pump before the compartment is empty and leave the pump in standing water if the other pump doesn't pump to the low level. If it does no need for a second low pump.
If there is more water in a compartment its a clear signal to check your pumps & switch.
I want my emergency pump to have the highest probability of working when needed and that to keep it clean, dry and unused for everyday normal bilge pumping use.

 

[rgano]

I reiterate, be sure there is an alarm on some bilge pump whether low or high to let you know before all is lost that water is getting into the people tank. I have audible/visual alarm on the first pump which would come on in my normally completely dry bilge, visual alarms on the next two in the bilge and big honking audible and visual alarm on the 4000 GPH high-mounted emergency pump. I also have a portable 120 VAC submersible with a water hose connection which can be run off the 300 Watt portable inverter, gen or shore juice; then there is the portable manual pump, all in this little 30-footer.

 

[jleonard]

I reiterate, be sure there is an alarm on some bilge pump whether low or high to let you know before all is lost that water is getting into the people tank. I have audible/visual alarm on the first pump which would come on in my normally completely dry bilge, visual alarms on the next two in the bilge and big honking audible and visual alarm on the 4000 GPH high-mounted emergency pump. I also have a portable 120 VAC submersible with a water hose connection which can be run off the 300 Watt portable inverter, gen or shore juice; then there is the portable manual pump, all in this little 30-footer.

I guess I have a much higher risk tolerance than most.

 

[sford1952]

Wow, happy to hear these excellent suggestions, I feel as though I've gained years of experience due to your generosity. rest assured I will be installing extra bilge pumps to preserve our well being as well as our trawler. You are all my Friends now. Thank you sincerely. Steve & Alexa

 

[tn6437]

hi, nice to see another chb 35 owner. mine is a sundeck. under the step by the helm there is an emergency manual pump. when i added a second pump for emergencies i used the thru hull from the manual one. i still have the manual one connected, i just used a tee fitting with check valves on both hoses to prevent and backflow. wired it to a spare breaker on my panel as well as a constant hot line.

 

[kthoennes]

Sort of startling that a 35ft boat would only have one bilge pump. I'd not be surprised to find that it's a small one at that. I guess the assumption is that you'll never need it.

That was my first thought too. I know "Mainship" for my 1996 boat is pretty much a different company pre-Marlow, but it's really surprising to me that Mainship only installed one in that model. I have 5 -- three regular bilge pumps (fore, mid and aft) and then the two shower sumps which are only 800 gph each, but still. If I'm trying to buy time with a bad leak, I'll take every gph I can get.

 

[HTurner]

This may be of some interest:


https://www.practical-sailor.com/blog/bilge-pump-installation-and-maintenance-tips


There is a section about tandem pumps...