Bilge Pump, technical question?

[brackish]

Is it considered poor practice to, in some manner, T a manual bilge pump and an electric bilge pump to use the same thru hull?  Seems that in an emergency you might need both operating at maximum so that might be the answer, but any opinions?
I'm about to install an electric with an automatic option, trying to decide on the additional thru hull, hate those holes in the boat.  My installation guide says no check valve on the pump.

My boat stays in the water uncovered most of the time and without an inboard with the associated packing gland issues, the bilge has remained bone dry since the day I got it.  The previous owner never installed a bilge pump, but I want one in the event of some catastrophic event or some leak that might occur when it is unattended for long periods of time.

[Salty19]

Hi Brack-

I'm with you on this.  My bilge is bone dry as well, but you never know will happen.  I was going to install an electric pump as well, probably later in the year or over the winter.  Maybe the rule 750?

In the Chpaman's Piloting and Seamanship guide (pretty much the bible for boats), it does state to NOT use existing plumbing for new bilge pumps.  The reason was what you mentioned (flow issues). It also suggests that a failure/sticking of the t-valve will cause both pumps to not function properly.  That's a single point of failure for an important function, and they are not exactly bulletproof.   I'll do it "right" and put another thru-transom fitting on it.   Have lot's of time to plan and figure things out.

[crazycarl]

When addding a new thru-hull, make sure of it's position.  (ie height above waterline) I would also recommend  upgrading to a pump that allows a check valve.  I was in the Keys recently, surfing down the waves for over 8 hours.  When I dropped anchor for the evening, the bilge had overflowed into the cabin.  I went overboard, and a full inspection of the boat showed no damage.  Climbing the stern ladder I spied the bilge thru-hull.  I believe the waves went down the tube and flooded the boat.
(it didn't have a float switch)

Also remember, bilge pumps are designed to remove small amounts of water from the bilge at a given rate.  They are not designed to keep a boat from sinking.  A quarter size hole will let in 4,000 gallons of water an hour. 

[Bob23]

Hmm... quarter size hole lets in 4000 gallons per hour. That's a lot of water.
I installed a Rule electric pump in my 23 a few years ago. 1500 gals I think. I ran a completely separate line to a new thru-hull located in the stern, fairly high up. Everytime I've tested it, it has worked fine. I also installed a new check valve in the factory pump. I like the idea of 2 separate pumps just in case. My bilge does not stay bone dry. I think some water enters into the anchor locker, runs under the cabin floor and into the bilge. About 1/2" is all that's in there. Not bad for a 26 year old girl. If that's the most trouble she gives me, well I can live with that.
Bob23

[Craig Weis]

1~No New Holes.
2~The electric bilge pump ought to be 't' ed into the discharge hose of the Guzzler Manual Diaphragm pump.
3~That puts the electric Down Stream of the manual. The manual pump is the check valve.
4~Both pumps will discharge out the one factory hole with a flapper valve at the port.

First Picture just shows the pump's switch. Right next to all the st'd. s/w pan'l. Auto-Test-Off.

Second pump shows bilge pump mounted on to an aluminum angle that is epoxied to the fiberglass after the grey bilge paint was removed. The pump just snaps onto a strainer, that I glued to the aluminum angle.

The pump does not pump very much very fast, about 75 gallon per hour. Largest capacity pump WetMarine had that was 12 volt. Or about 1.25 per minute and is circut breaker protected. No fuse to fiddle with if it blows. Just push in the breaker and your good to go again.

Actually I buy a bag of crushed ice and bury the pump then add my favorite adult beverage and cover with more ice. At the end of the ice, I cycle the pump to clear the bilge. Lasts Friday to Sunday. Yes I have to move the potty to get a beer. But it's a small boat.
skip.

[bmiller]

I don't think I'd like the manual plumbed into a tee with the electric. You'll pump right through the elctric with the manual and effectively recirc the water.

On another note make damn sure there is a loop above the absolute high water line. The previous owner replumbed the electric pump, without a loop. When healed over to port sea water backfilled into the bilge and found it's way into the port side locker under the settee. Pretty scary for a few moments there until we got it figured out. A couple bucks of hose and a barb fitting and as was well again. That's how I found out you can pump right back through the electric pump.

[botelerr]

The bilge doubles as the chilled adult storage unit .. Maybe the CY guys need to revise their literature? I like it,, now I need to find the handle for the pump...the river is rising.................RBB

[newt]

You might consider putting the pump with another thru hull, for example the cockpit drain.  I agree that it should not be T'ed into the manual pump, but there are other thru hulls you can look at. There is one for the sink, but in a knockdown on that side I had it bring in a couple of gallons of water before she popped up, so that one is closed with a valve for me. Then there is two cockpit drains, and then I have a thru hull out the transom which the wires for the outboard go through. Finally I have the bilge thru-hull. So one of them ought to work.
Just remember one thing...The drain coming from the auto pump must not have a closed valve, but the other tube should. To make the thru-hull a bilge drain, you need to have whatever other tube going in closed off. That means only one cockpit drain if you have the bilge pump on. Something to consider if you are in heavy following seas. (Like your going to take your boat out in those conditions )

[Craig Weis]

The manual bilge pump handle is 'snapped' into a holder that is attached under the settee lid and clearly labled. Any guests on board are made aware of the location and proper insertion. The manual pump is below the automatic discharge and clamped right up against the ridge that the settee lid sits on. It's all down hill to the scupper.

skip.

[CaptRon28]

The best arrangement for an automatic bilge pump would be a dedicated hose and thru-hull that exits well above the water line and has a loop that is even higher than that point. A check valve could negate the last requirement, but they are notorious for failing and causing problems, especially when used with a water source that may not be totally clean (like a bilge, shower drain or sea water trying to get in). I suppose it could be relatively safe to prevent some bilge water (in the hose) from draining back into the bilge IF the discharge is above the water line and has the loop, but never rely on one to keep sea water out.

[brackish]

Thanks for the thoughts.  I believe I will install a dedicated thru hull with a high loop.  Stern is kind of busy, may go with one on the port side somewhat aft of center, maybe take the loop up into the coaming.  On my last boat, installed it there, never had any functional problems.  At that head, this Rule 1100 should still be good for 6-700 GPH

Newt, that sink bothers me too.  Thru hull is maybe 5 or 6 inches above the water line with no loop (probably would not drain properly if it had one).  Not the highest quality hose, probably has to be that light corrugated so the sink will slide. Think I'll install a valve at the thru hull and leave it normally shut.  Don't use that sink very much anyway.

[Salty19]

newt, you bring up a real good point that I thought of last night as well.

Instead of a new thru-transom fitting, we could always put a new thru-hull on the interior of the cockpit (perhaps the gas tank storage area).  No backwash problems, no special hose arrangement or off valve needed. Bilge water would simply empty into the aft cockpit floor and out the existing scuppers.  Also that would not require cutting into the scupper pipes which could cause a leak down the road (not to mention it looks difficult to access this area).

The risk here is plugged scuppers and in a situation where the boat is swamped and cannot drain properly.  However at that point (with hundreds of gallons of water in the cockpit), the boat is practically doomed anyway.

Let us know what you come up with, brack...I may just copy your configuration.

[newt]

I think you guys are headed down the right road. I mean you understand the concerns, esp backwash into the bilge.  Keep the people inside the boat, the water on the outside and the stick in the air...

[bmiller]

Hey salty, bilge water in the cockpit? Might get a little stinky on yer feet.

[Joseph]

If you are thinking real emergencies I'd go for the the manual one. Electric ones go when the batteries go, perhaps sooner... Most electric bilge pumps are just to keep the bilge at a minimum during normal water inflow and they are great to conceal or sometime to reveal (depending on how much attention is paid to them) small leaks. I once chartered a boat in the North Chanel of Lake Huron with a puncture in the engine raw water intake hose below the level of the residual water in the bilge. The only way to discover it was to pay attention to the electric bilge pump switching on every few minutes.  Just for that reason I tolerate them, but in a real emergency I'd rather trust more a manual pump and a regular ("on the hour" was the recommendation from the old salts) visual bilge inspection followed by a full drainage counting pumping actions. Of course, as the saying goes, the best bilge pump is a scared sailor with a bucket in his hands...

J.