Open boat electric bilge pump system ??

[bsfreefalllt]

I picked up a used caption not too long ago and had the pleasure of learning how to roll it this last weekend thanks to Foote's awesome video. Problem is once I roll it up, there must be 50 gallons of water in the boat. I love outfitting boats anyway, so I've decided to put in an electric bilge. I've found websites, opinions, etc...but I have a couple of specific questions that hopefully someone can help me out with.

Should I go with 2 pumps...I think I will because I want it to empty as fast as possible. Which 2 pumps should I use...I realize that the manufacturer ratings are bogus, so can anyone recommend a pump that is good. If I go with 2 do I hook them to the same battery and do I do it in series and does this affect how I setup the wiring, fuses, etc. Physics tells me it does, but I need some practical advice. I want to do it as light as possible because the boat weighs a ton already...what's the deal with lithium batteries not working when cold??

[gumpy]

Congrats on the roll!

I've often considered two pumps myself. Definitely don't wire 2 pumps in series. A parallel circuit ensures both pumps get the 12 volts they're designed to run on. I think mine uses a gel battery.

[Jim P]

I've outfitted several boats. Single pump, double pump... Attwood 1250 offers the best performance w/regards to water pumped vs. power consumed. Keep your discharge hoses as short as possible for best efficiency.

Run parallel - one switch one battery. If you run in series you have two problems - you double the voltage and if one pump fails both are out. Parallel just doubles the amperage/draw, you still use a 12 volt system. My description parallel vs. series is a lay mans version, I am no electrical engineer, someone else can probably do a better job with the explanation.

A Small SLA will work fine - 3.2 amp/hour about 2 lbs and cheap. With SLA you can forgo the battery boxes and stuff you NEED with Lion batts. Thus you can resort to KISS when building a system.

Of course if you take on lots of water you might drain a small battery in less than a day. But then you just resort to stop and dump, buy a bigger battery or learn to run drier.

[Jim Michaud]

I paddle a Caption with two Atwood 1250 pumps installed. I mounted them just far enough in front of the saddle that I could still use a bailer. I mounted them side by side with each pump close to the bilges. When the boat is almost empty I tilt the boat to one side so that one of the pumps almost completely empties the boat.

I would recommend a switch for each pump so that you could turn off the pump that's out of the water. It will also save your battery from running down too soon. The switch seems to be the weak part of any system so two switches will give you some redundancy.

I don't use any fuses and the only part of the system that I waterproof are the switches. Water will drain the battery over time so I mount the battery off the floor and I keep all of the wiring connections up high. I use a lead-acid battery mainly because I'm too cheap to spend the money for a high tech battery.

[marclamenace]

Ni-MH batteries are the best, forget about expensive and environmentally detrimental gels or other types.

Also forget about the fuse: use a battery pack that can't develop much more than the amps you need so won't ever toast the pump.

I use 12 x Ni-MH AA 2750mA in two battery 6-packs squished in a pelican 1010 case, which has also the switch with water-thigh rubber cap mounted into. It is pretty small, very light. I could send pictures if you pm me.

I agree with the attwood 1250 being a great pump, I have their newer version Tsunami pump, lighter and smaller pump with pretty much the same performance.

Have fun!

[OC1er]

I've put pumps in about 5 boats, I've found the simpler the system the better the system. I don't use fuses and have never burned out a pump, just use the right battery as someone said above. I've only used the Attwoods. NOC used to sell a kit from esquif with everything you need. I found that esquif's pump to power / switch connector is unreliable, especially if you ever do roll clinics in the pool - the pool chemicals caused corrosion or some kind of build up.

I've been using a pelican box (6x4x3?) to hold my battery and switch. I drill a hole in the lid big enough to allow the moving part of the switch to pass through and glue to body of the switch to the under side of the lid (so when you open the lid the switch swings up with it). I also drill a small hole to allow the two wires running off the pump to come into the box. This keeps all the connections in the box and dry (ish), and it keeps the wires as short as possible. Before I built another of these battery / switch boxes I used to switch the one box between my zoom and prelude, I've got places to strap the box in on both boats. So far it's proved pretty reliable.

[Jim P]

Forget about connectors - use only where needed. Solder everything you can - like the switch and battery connections. Only use a plug connector between the battery and switch. Cheap plugs will eventually corrode and stop working, but a quick polish of the contacts with some steel wool and they work like new again. Just stash a quarter sized piece in your drybag for that once or twice a year buffing, cause you never know when it will fail.

Fully waterproof switches can be had, you might need to do a special order but even then only $12 - $15 each - no need for boots or boxes. I used to use a box to make it easy to move from boat to boat, now I just mount a switch in each boat, and move the pumps as needed.


Simple and light.

[Tiggy]

They do make connectors that seal themselves with a heat gun. Companies name starts with a G" and for the life of me I cant remember. They are somewhat pricey but do the trick. If you are running a 12 volt pump, make sure your battery voltage is like 14 or more volts. This will increase the battery life. I have an Atwood 1250 in my ocoee, it drains before I blink, 14.4 Ni MH batteries. Batteries are the most expensive part.
I also found some "through-the-hull" parts that work for wiring through the dry box. Bailing sux.