Bilge pump test / advice

BiteFactory · 03-28-2006, 08:11 PM

I have two Rule bilge pumps. One is a 900 on manual and the other is a 1200 on auto switch. Both mounted in the stern lowest section, side by side. Did a little test this weekend by pulling the plug from the inside and letting it fill until the auto switch (Rule float switch) kicked on. It took it's sweet time, I'll give it that. The water came in with good pressure.

With both pumps on it was keeping just ahead of the leak.

This doesn't bode well for wave removal. Since I don't have a self bailing deck this is the only way it's going to get out.

I see two problems - first need bigger pumps. Second - the outflow ports are up pretty high, just under the rub rail. I read that the gph flow is measured with the outflow level with the pump. I figured it was better this way, less potential for backflow. It is also the way the first pump was installed at factory. I have also made very sure both pumps have good power/ground access.

Any recommendations on improving this? I'm not looking to make this boat anything more than the inshore / fairweather platform it is.

20' NR Seahawk, offshore platform, full transom.

Reelentless · 03-28-2006, 08:46 PM

Have a manual pump and a bucket on board. You'd be suprised at how fast you can bail water when [petunias!] hits the fan.

Make sure you have adequate battery capacity to run the pumps as long as possible.

Short of replacing the pumps with some with more capacity, it sounds like you have done all you can.

You are aware of the limitations of your boat and that puts you well ahead of a lot of people.

Onokai · 03-28-2006, 08:49 PM

Bigger pumps -less head to pump up and larger outfeed hoses as well as short as possiable-Pack a whale manual pump as well -when the power dies.-
Your test says alot about how safe that vessel is when taking on water. Mark

blubeast · 03-29-2006, 06:40 AM

Biggger pumps.

Also on your auto pump, do you have a dash light that shines IF it should activate? If not, suggest you take the time to run one inline with your pump power line. That way if so some reason you're raking on water and you were not aware of it, you'd have a visual indicator a problem exists.

Metal Manipulator · 03-29-2006, 06:46 AM

This is a very good idea for both the bilge pump and the engine compartment blower. When youare trolling you can't hear either and both will run your battery down. I know from experiance, and now I have both.

mglafarge · 03-29-2006, 06:58 AM

One other thing I have done on my I/O boat is to put an extra float switch in at a level above the pumps that is hooked up to the horn so that at a dock if a hose were to break it would aleart people around the dock that something is wrong with your boat if you aren't there..

Herring Problem · 03-29-2006, 07:32 AM

I placed three 2500 GPH pumps with float switches on my last boat. Ran 11/4 inch lines to three stern exits with the least amount of hose needed from each pump to exit point.
As all of the water went to the bilgde and was discharged from the transom area. Had the pumps located at three different 1 inch heights in the boat to compensate for the water levels as needed..
Only once on the ocean was I glad I had those pumps, got caught 20 miles out in a Northwester with waves and spray and more rain than I have ever seen. Took on lots of water and those puppies did a great job.

bait boy · 03-29-2006, 09:56 AM

I just did the math on fishtales bilge pump installation, and if working at rated capacity it could remove approx 2.5 gallons per second. Thats a whole lotta water leaving like now!!!! I cant even get my deck to drain to the bilge that fast

fishitis · 03-29-2006, 05:24 PM

bait boy brings up a good point. Your deck probably won't drain to your bilge as fast as your pumps will pump. My NR Seahawk deck drains to the bilge very slowly - as evidenced when I am washing down the deck. I've notched the deck boards at the stern to allow water to drain to the bilge faster. Many options here for where you put drain holes. I'd check your deck draining ability.

BiteFactory · 03-29-2006, 06:34 PM

Hey, thanks guys. Definitely bigger pumps and I'm thinking about those other auto switches that don't use floats - witch something. I don't have any holes in the hull anywhere near the water line. Outboard on a platform, no washdown pump inlet.

Remember about those pumps though - the ratings are not really in tune with reality. Once you hook a hose up to them the gph starts going down, if it must pump up then even more. Full power/ground capacity also assumed in rating.

I have noticed that the deck doesn't drain all that quickly to bilge when washing it down. I didn't think about it in this context though. I think I will be making some drains.

ICHTHYDEMON · 03-29-2006, 07:04 PM

Quote:

Remember about those pumps though - the ratings are not really in tune with reality. Once you hook a hose up to them the gph starts going down,

The standard corrugated bilge hose cuts down on flow as well. I can't remember where I saw it,but I saw a side by side comparison between corrugated and smooth wall hose. The smooth wall hose flowed considerably better.

I think I also saw that a bilge pump looses about 20% of its rating for every foot in elevation it has to pump.

Makes a case for cramming the biggest pumps you can find down in the bilge.

I've got a 900 and a 1250 in my Seahawk right now. I also have a 2000 I'm installing in a couple days.

Pilar · 03-30-2006, 04:13 AM

'Kismet' has three 1100 GPH pumps, one forward in the cabin bilge and two in the engine room forward of the engine. I am considering adding a fourth pump to get the last bit of water that can pool under the flywheel on the motor to protect the starter from slung water. The deck on 'Kismet' is drained by scuppers to overboard and does not drain below decks. Perko has a new deck scupper that is clog proof and does not use a screen. It has a 1-1/2" hose size and so far works so much better than the setup I replaced.

Good points raised regarding capacity, hose type/size and pump head. Some other things to consider here.

Beware of siphon and setup the overboard hose so that this is not possible. The scenario is flooding at the moorage, the battery goes dead, the pump stops and the water siphons back into the boat through the hose. Many more boats are lost at moorage than at sea.

Make sure the wiring to the pump is properly sized to minimize losses. Refer to the online wire sizing guide at the Ancor website and count every foot of wire, hot and ground leg, in your calculations. Also if there is any place on your boat to seal all electrical connections with heat shrink and liquid vinyl tape this is it. Some of the wiring is immersed in saltwater so use quality marine wire and good lugs. The two conductor white jacket wire is ideal since the wire will not get nicked and rot with the extra protection. All it takes is an insulation cut, a corroded lug or splice on the ground wire or power wire to restrict the power available to the pump or stop it. The wire run length is usually pretty long and at 12 volts the voltage drop is considerable. Use number 14 awg or even 12 if the total run length is more than 30 feet. The wire size calculator at Ancor will show you what size wire to use.

Dont cheap it

Something else to worry about is debris clogging the housing/screen. Bull kelp, sea lettuce, paper, plastic bags and spectra fishing line are all show stoppers on your bilge pump. How the water gets to the bilge and how much stuff it can wash there is important to consider. Can you quickly remove the pump to clean the screen? On some boats you can't even reach it very easily. Spectra line will go right through the screen and spin onto the pump shaft, stopping the pump and blowing the fuse or breaker.

As far as fusing and breakers go. Individual fuses are best. This is not always possible but if the fuse blows and all the pumps stop ... not good.

On boats that will be moored you need a specific setup to protect the boat. The pump should be wired with two circuits. One circuit is float actuated and wired directly to the main high capacity house battery. Use a fuse here that protects the wire, rated for 10 to 15 amps not the usually 5 amps for the pump. It is very important that the pump cannot be isolated and disabled by the battery switch. The second circuit is the usual fuse and manual switch we are all familiar with.

BlueBeast mentions a light. You can get a flashing red light at Baxter Auto parts. It is $10 but very hard to ignore. By using diodes (1N4004) you can make one light check all pumps. Any pump runs for any reason and the light flashes. I'd much rather know if any water is pouring into the people tank before it washes over the deck and becomes obvious. On 'Kismet' I have rigged a bilge alarm light for three pumps in two places. One on the bridge and one below in the cabin. Like I said very hard to ignore the flashing red light.

CAPT KUJO · 03-30-2006, 04:24 AM

The BLACK ROCKET has 3 - 1000 gph pumps but more importantly has four 3" deck scuppers that will drain a
6 ft plunging breaking in the boat within 45 seconds. You'll need alot of BIG pumps to match the efficency of deck scuppers. Can you retro=fit your boat with them? It's Alum and seem it could easily be done with a hole saw and 3" pipe. I can custome make "sleeves for them.

CAPT KUJO

slowbuilder2005 · 03-30-2006, 11:12 AM

Reelentless really gave the right answer. Keep a good bucket in the boat, especially one of those square ones that lets you scoop along a flat surface (deck). I did a bunch of calculations on water in boats one time and came to the conclusion that bilge pumps were hardly better than a convenience ...something to get rid of nuisance water in the boat, not something to get a wave out. Here's an example:

- Assume a wave came onboard and deposited 6" deep water in your aft cockpit area. Assume the cockpit area is 6' by 5'.

- The volume of water in the boat is 15 cubic feet. This is 930 pounds of water ...your boat will settle at the stern. Consider that you'll likely have 300 to 400 pounds of people and gear in the stern as well. The boat will be even more likely to take on another wave.
- The 15 cubic feet of water contains 112 gallons. A 2500 GPH pump will take 3 minutes to empty the boat if under ideal conditions. Given realistic rises for the exit tube, it'll likely take 5 or 6 minutes to empty the boat instead. How often do waves appear? Too often...

See my point? Having the pumps is better than nothing, but relying on them alone isn't safe. Better to have a bucket around. I heard somewhere that the most common cause of capsize was a wave over the stern, then another, then a capsize. A boat off Camano (or Whidbey?) Island in Washington just went through this exact scenario a couple of weeks ago and the conditions weren't even bad...

Brian

BiteFactory · 03-30-2006, 08:18 PM

Good points, thanks. I'll have to gnaw on this a bit.

Jeff P · 03-30-2006, 08:39 PM

I completely agree that a good bucket, or 3, is essential safety gear.

Looking at your example, a guy with a bucket would have to scoop and dump 28 buckets full (assume 4 gallons per scoop) of water in 3 minutes to compete with the pump. Each bucket weighs over 30 pounds. That's one 30 pound scoop every 6 seconds for 3 minutes. Since we are all in top physical condition, the adrenalized guy with the bucket would probably win this one.

Now, say you install 2 Rule 3700 pumps and have the 30+ amps to properly run them. Lets assume 3000 GPH each after losses. That's 100 gallons per minute. Now the guy with the bucket would have to scoop and dump every 2.4 seconds. Any takers?

I'm thinking 2 pumps and 3 guys with buckets.

KillerBeee · 04-03-2006, 11:45 AM

I need to upgrade my pump on my boat. I'm wondering which brand seems to be preferred and where are you getting them? I'm looking at 1 or 2 1000-1100gph pumps.
Beeeeeee

Metal Manipulator · 04-03-2006, 04:19 PM

Get the gas powered pump that coast gaurd drops on your boat. Don't have to worry about battery's and pumps alot of water.

Glad to see some of us thinking about these things. Saftey is a key thing on the Ocean, Thanks for keeping this going (saftey issues) it could save a life. I have three 500gph pumps, stern, midship, bow. plus I can pull the hose off of the fish box and pump out with the mercerator pump.

BiteFactory · 04-03-2006, 07:09 PM

Yeah, the CG pump! I daydreamed about a monster garage situation, how much water could I move out!? A rocket motor in a 5 inch tube that runs out the side - when it fires it causes a suction from a feeder tube and blows steam column out the side. Sounds like the start to one of those darwin awards - "milliseconds after hitting the ignition switch the boat was accelerated to around 90mph. After 2 seconds the boat was mostly airborne at 150mph as it crossed the beach. Two motor homes later the unrecognizable aluminum boat was at rest. The trooper on scene mistook it for a downed aircraft."

Metal Manipulator · 04-03-2006, 07:35 PM

Are you done knawing yet.

BiteFactory · 04-03-2006, 07:49 PM

Well, for this season I will probably replace the 900 with something beefier and swap my round bucket for a square one. Might swap the hose too for smooth bore. I may also put in drains from the deck to the bilge in each rear corner too - this I'll have to think more on.

See this pump test report: http://www.powerboat-reports.com/sample/bilge.html

DriftR · 04-04-2006, 11:56 AM

Yup, never have enough bilge pump capacity. Just remember this old saying," THE WORLD'S BEST BILGE PUMP IS A SCARED BOATER WITH A BUCKET." I am in the process of adding another 1100 gallon Rule to the monster that came with the boat. I also believe in adding a red light but also a small warning buzzer. That way when I'm in the cuddy I can still be warned with the buzzer if I don't see the red light go on. I always keep plenty of buckets on board as well as a extra long hand pump.