I have an old Geminicatamaran, it doesn't look like its ever had a bilge pump and im looking at my options and, since I would need 2 of everything im thinking of just buying a small gas powered pump that can be portable and take to where the water is. The boat has, or will have only one penetration below the waterline in the head, im installing an airhead and am glassing up the head outlet but retaining the inlet for the sink as I will be in the great lakes. So, any water that may enter would be from a puncture which would most likely only happen when im aboard, so im thinking that any sizable electric pump would drain the battery down pretty quick and I would need one in each hull. The boat only has a group 24 starting battery and a group 27 house battery and I don't want to add more as I don't have the means to charge them (outboard) I was just looking at a Subaru 4 strokepump yesterday that pumps 28gpm and weighs very little and could easily store in a cockpit locker ready to be used wherever needed and I would be using a fuel I already carry so could run it for days if needed. Thoughts?
I like your idea of carrying a very high capacity pump. Since it will likely be unused for long periods of time, I worry that it might not start when you need it to.
I think I would install a small electric pump in each hull as well. It's amazing the ways water can find to get into boats. A lot of boats get sunk by rain. With luck you'll never need them but I know I would feel better having them there.
Retired from Hopkins-Carter Marine Supplies
Until just recently, they never installed bilge pumps. Not that they shouldn't have but if your bilges have water in them there is an issue you should be addressing.
Would the pump be remote mounted? You might create a different issue if you run a gas engine in an enclosed cabin.
As HopCar said, I would be worried that the gas engine that has set in a hatch for the last 5-10yrs doesn't want to start when the emergency happens.
I would look at a couple of big electric pumps with automatic switches (plumb them to the center board trunk air pressure relief hose.). You can always crank up the main engine to keep the batteries topped up if you are away from shore power.
My point is that I only have an outboard so not much charging capacity. If I were to keep the boat at a dock I would use 110v pumps, ive seen a few boats that have sunk in the marina because something failed and the 12v pumps only delayed the inevitable. I agree that starting after sitting for a while may be the Achilles heel for a gas pump but ive had very good luck with Honda generators.
Steve, I'm with you on Honda engines. I've had pretty good luck with them sitting for long periods of time and then starting. You had mentioned a Suburu powered pump and I have no experience with them.
The ideal stand by pump would be fueled by propane. The carb never gums up and the fuel never goes bad.
That reminds me, it's time to start my hurricanegenerator. I always start it once a year in June. It's more than ten years old and has started every time. It's a tri-fuel generator but I've never put gasoline in it, only propane.
You don't need to use 110 Volt pumps at the dock. Just get a battery charger that can supply enough power to run the pumps without drawing down the batteries.
Retired from Hopkins-Carter Marine Supplies
The US Forest service and BLM carry something called a "trash pump" on the fire trucks. It's a little 2 stroke pump that makes a hell of a racket when running but does the job. I have no idea about it's reliability.
Ridiculous idea. You'll never need it. It will only be useful in a special situation. Day-to-day one should have no water - at least no more than a sponge can handle. If you get seriously holed no trash pump is going to save the boat.
That and it probably won't start when needed without a serious maintenance program.
A 1500gph rulebilge pump (roughly equivilent) 12v pump draws 4.4 amps. The 25hp merc on our gemini puts out 7 amps.
- If only one bilge is flooding the outboard will keep up indefinetly.
- If both are going full blast (almost twice the output you are proposing), you are loosing less than 2 amp-hrs per hour from the battery bank (8.8amp draw - 7 amp output = 1.8amp from batteries) Assuming say a 50 amp-hr battery bank (pretty small), that give you 25 hrs of pumping.
In addition, the bilge pumps can be installed with automatic pumps, so they kick in even if you don't notice the leak.
When you run the numbers, you find there is a reason electric bilge pumps are typically choosen.
Ok, I wont go the gasoline pump route, i am going to use a 110v submersible pump as an emergency pump and run it off my Honda 1000e generator rather than install 2 separate submersible 12v pumps (catamaran). To be clear, i don't have any leaks and only 1 hull penetration so it would be for emergency use so needs to be a reasonable size. The Gemini has huge, flat floored cockpit lockers where the Generator lives but sits on the cockpit sole or seat when running, if i buy a 3300gph pump it will be very mobile to use in either bilge and be able to run for as long as i feed it fuel and i can be fairly certain the generator will start as it gets regular use and maintainance. Im not concerned about the boat sinking on its mooring as it is usually a failed hose or through hull that causes that unles someone runs into it.
My yachtclub has three portable pumps for emergency dewatering of boats. We may be the only civilian facility with this degree of preparedness. One is a small electricalmotor combined with a centrigugal pump, used for emptying dinghies of small bilge leaks. The intermediate one is a submersibe, electric, that pumps about 1500 gallons per hour and cost about $1000. The big one is the civilian version of the Coast Guard's P-6 gasoline-powered pump. It cost almost $6000 (yes), requires a regular preventive maintenance program (the document for this is online), and can act as an emergency firehose for a boatfire, and pumps about 3000 gallons per hour. We train on these units regularly to ensure they are ready to use in an emergency.
My recommendation is to install a Whale or Edson manual bilge pump, mounted on a portable board you can stand on. Use a length of swimming pool supply corrugated hose with rubber collets as the pickup line, and let the discharge simply exit the pump when pumping on deck. And then, add one (or two) Rule 3500 automatic bilge pumps for a fixed installation. That's what I use on my trimaran.
What do you do when the water has risen to the level of the batteries? Never, ever, depend exclusively and primarily on an electrical solution. Install a manual backup system, sized to move a lot of water, specifically the Whale, or better, the Edson pumps. All the other suggestions are creative, but depend on stuff working when conditions may be less than optimal. And if they fail? What is the fallback position, a bucket?
I would install 2 automatic electric bilge pumps and 2 manual backups. Put a decent (15 or 30watt) solar panel with a charge controller on the boat also. That way even if you are silly and forget you left a hatch open for a week or two without visiting the boat won't kill the battery dewatering from rain storms and sink.
My yachtclub has three portable pumps for emergency dewatering of boats. We may be the only civilian facility with this degree of preparedness. One is a small electrical motor combined with a centrigugal pump, used for emptying dinghies of small bilge leaks. The intermediate one is a submersibe, electric, that pumps about 1500 gallons per hour and cost about $1000. The big one is the civilian version of the Coast Guard's P-6 gasoline-powered pump. It cost almost $6000 (yes), requires a regular preventive maintenance program (the document for this is online), and can act as an emergency firehose for a boatfire, and pumps about 3000 gallons per hour. We train on these units regularly to ensure they are ready to use in an emergency......
Wow! That is a (truly) impressive level of preparation.