Bilge pumps

[roly_voya]

Doing final fit out on a 35ft ready for long distance stuff (been living aboard around uk for a while but cant decide on bilge pumps. Given that everything I possess will be on board not sinking is a priority and a large power pump seams a good idea just in case. Looking at potential flooding rates if I loose a seacock or prop shaft seems to sugest something in the order of 50-100gal/min. Just to compound things she is a traditional wooden boat with a very deep bilge sump and only limited access because tanks and engine also live down there. So lift is about 5ft and pipe run to transom would be about 20ft. Looked at engine driven and problems with fitting pump to engine, also don't like relying on starting the engine as it may be flooded or at least the belt might be because deep narrow sumps initially fill quite quickly so thinking of a 4 or 8000 gal electric job. Any ideas and what have others done? /forums/images/graemlins/confused.gif

 

[boatmike]

The simple answer is to fit several submersibles as they are relatively cheap and easy to install. Those working from a float valve (automatic) are to be preferred and you can wire them up (or at least one of them) to a seperate switch by-passing your battery isolator switch to leave them on when the boat is not at sea.
As far as size is concerned fit the biggest you can afford.
I also believe in keeping at least one high capacity manual pump as a back up.
Finally dont forget the old saying. There is no bilge pump as fast as a frightened man with a bucket! Keep one at hand......

 

[Trevethan]

100 gallons a minute is a hell of a lot of water to shift -- 6,000 gallons per hour -- and the only power source available with that kind of muscle for any length of time is likely to be the engine.

But Rule do some big electric pumps up to 8,000 gph, but the current draw is pretty intense -- 20 amp hour for a 3,750 gph model
Also remember though that rating will be lower in real life due to the water head -- its also dependant on fully charged battery state.

There are some flow graphs here
http://www.rule-industries.com/rule/prod_charts2.asp

You can also get shaft mounted pumps. I have also heard of solutions that can divert the raw water inlet to a hose in the bilge which could help in emergency but I'd want to keep a very careful eye that it didn't clear all the water out or the strum box got clogged letting the engine over heat, which you tou are dealing with major leak, you might not be able to do.

The system I have is as follows and I know that if the worst happened all I could do is delay the inevitable!

I have a Whale gulper as my primary pump -- pumps everything including sand water mix, hair, matches, everything that falls into the bilge just about . Not huge capacity about 5 gallons a minute but very reliable

I also have a a pair of Rule 1800 submersible, one automatic direct to battery via fuse, the other manually switched and finally a Henderson manual pump

Best solution is keep a ready supply of soft wood bungs just in case!

Hope helps,

Nick

 

[iangrant]

The alternative and probably the best option is to fit an in line self priming pump activated by an air pressure switch, wired with an overide switch. I mounted mine in the engine compartment with the hose down into the bilge. That way the pump/filter is where you can see it, I carry a spare.

Jabsco do all the best pumps but they are not cheap. I fitted a mesh filter on the input.

Usual plumbing fitting nightmares, man behind counter sucking on teeth!!

Good luck

Ian

 

[AndrewB]

Rule flow graphs.

[ QUOTE ]
There are some flow graphs here
http://www.rule-industries.com/rule/prod_charts2.asp


[/ QUOTE ]These are decidedly optimistic. The advice given on the boxes is for much lower performance e.g. the 500 and 800 nominal gph say 2 meters head is the maximum for any flow, 1100 gph is 3 meters. I have recently confirmed for myself that for the 500 gph unit, 2 meters is the absolute limit, and that only on a straight lift with no loops etc.

 

[TigaWave]

Having been on a boat that sprung a large leak....the first thing we noticed was the electrics, we were motoring at the time. Gen light comes on, alternator was already under water, and engine and gearbox near to stopping.
My approach for what its worth, was to make sure all through hulls were always easily accessible, and there were duplicate bungs for hull size hole and pipe size hole available on lines close by. I also ensured the pick up end of the pump was also quick to get at, as you can guarantee it will be blocked with a piece of paper when its needed, I fitted the biggest electric I could, with heavy duty wiring to the batteries direct...and felt quite happy. If your giving it this much thought then you'll have thought through the various scenarios of what ifs...so you're as well prepared as you can be... have a good trip.

 

[scarlett]

I have not done this as I live on a small Etap in the summer. But if I had a big boat and was worried about sinking under the circumstances described I would follow the advice about the plugs and would install a small hand start generator high up in the cockpit. I would run two circuits off a switch on this, one to charge the batteries etc. and the other to a series of submersible pumps. And have some water level alarms.

I have a water level alarm and several immersible pumps, one on auto, on my little unsinkable boat.

Please don't sue me if your boat sinks!

 

[Anonymous]

I have a Jabsco with the exposed motor and drive belt. I have had mine apart and rebuilt it. The spares are all available and it is made in such a way that it is possible for a yachtsman to fix it with normal tools etc. provided you have a spare diaphragm kit. I would recommend it if for that reason alone.

If you have adequate bilge alarms you should notice a problem before a seacock fails - it is unlikely to just suddenly break off without becoming very leaky for a while first. What you don't want is for an automatic bilge pump to merrily pump a couple of gallons an hour unheard due to engine noise, without warning you. Options are a buzzer whenever the bilge pump runs or (as I have done) a klaxon if the pump runs for more than a pre-determined time. If you have some warning you can sort the problem out long before the leak becomes anywhere near as great as 50 to 100 gpm - which is a huge flow. 100 gpm is the equivalent of fifty full buckets of water every minute - nearly one a second!

 

[RobinC]

Doing a lot of internet marine research and found this the other day - which might help - http://www.yachtsurvey.com/bilge_pumps.htm

Robin

 

[Becky]

We have recently investigated the type and number of bilge pumps for Cornish Maid. In discussion with a knowledgeable swindelry salesman, we went for relatively small Rule (500gph I believe) on the basis that we would have problems with exhausting the batteries with a very bad leak. It was pointed out that running a very powerful bilge pump would shift quite a lot of water ( less than the manufacturers say, and American gallons are smaller) but not for very long because the batteries would run down. In other words, a serious hull breach cannot be balanced for very long by electrical pumping. You have to stem the flow somehow, a parasol thingy to poke through the hole, or a wooden bung.
HWMBO intended to fit the biggest bilge pump we could find, until he saw the current draw! So we compromised. Not sure it was the best choice, after reading the article in Robinc's post. /forums/images/graemlins/confused.gif
A portable pump with an inlet pipe that can be taken to the worst part of the inflow and an exhaust pipe that can be aimed over the side seems to me to be a good compromise. Still got to buy it though.

 

[charles_reed]

I've got 3 automatic electric and 2 manual (MOE) pumps.

The electric pumps will move about 4500 galls/hr and the manual depends upon stamina, levels of adrenaline and strength.

Only once had an effulgence of water, caused by a leaking stern gland. Writing up log in saloon, put foot on sole and got wet foot. I was in a marina and the auto bilge pumps were off but they and about 8 mins manual pumping cleared the bilges.

That was literally a trickle and I hate to think of the effect a hole in the boat makes.
I've seen a couple sink, if you get the problem early enough and slow the rush you have a chance - if you leave it until the cabin sole is awash you're unlikely to succeed. read a post aon another board from an American who had a 10Kgalls and hour portable pump and thought himself sinkproof. He delayed getting into the liferaft by (his estimation) 90 mins, by which time the CG had arrived with a big pump but they were all unsuccessful in keeping the boat afloat.

So, I infer, no number of pumps will save you from collision holing.

 

[roly_voya]

Thanks all, just got back from a terminal computer crash - processor failed

 

[PaulJ]

My feeling is that if you get anything more than a very small hole, the boat is lost anyway. My advice would be to install the biggest pumps, both manual and electric, that you reasonably can and just hope that it is enough for whatever particular misfortune befalls you.

In my case the boat (39footer) divides conveniently into a forward section and an aft section either side of a particular frame. The forward section has a Rule 3500 (electric + float switch) and a Whale Gusher 30 which can be operated whilst sitting comfortably on a cabin seat. The Aft section is served by two similar pumps, the Whale being operated from the cockpit. All pump through 1 1/2" hose through the transom about a foot above the waterline.

I know that these pumps will not be enough to cope with a "serious" hole but I hope they would cope with say a failed sterngland or a failed seacock for long enough to give me time to do something about the leak.

I think you must install both electric AND manual pumps but whatever you install will not be enough to cope with a big hole. Just install the biggest that you reasonably can.

Paul.

 

[hlb]

I've just had fitted a bilge alarm system, with a big claxton thingy attatched. My biggest worry is a bilge pump packing in whilst I am away from the boat. My new devise will wake the whole marina to the problem!!