bilge pumps

[ddeaton]

Where is the best place to run the through hull fitting, or fittings for the bilge pumps? I have 2 under the water line for the cockpit scuppers, but I cant figure out where to plumb the bilge and make it look good.
Thanks,
Danny

[formerlyknownasprince]

Depends.......

lots of depends there.

What sort of boat are we talking about? Pics?

[seo]

A good arrangment is to put a tee in the cockpit drain line, right under the cockpit sole. This assumes you've got enough freeboard. If water never comes back up through the drain, you've got enough freeboard.
The advantages are:
1) It's a vented drain, so there's no possibility of back-siphoning.
2) It's below the waterline, so won't leave streaks on the hull. Also discreet.
3) It makes an audible gurgle when the pump is running, so you can keep track of it. Otherwise, when underway you often can't hear the pump above the sound of the boat.
4) If the drain line plugs up, the water will back up into the cockpit, flow across, and out the other drain.

This won't work well in the winter, when the cockpit drains should be shut off and flooded with anti-freeze. But if you haul out in the winter, or live down south, no big deal.

Most manufacturers run the discharge out the stern. Works okay on a boat with sawn-off transom. Much less well with a long overhang and counter stern, where the stern wave can cover the discharge fitting, and cause back-siphoning. This can be prevented by putting a vent line at the top of a riser loop.

Same's true of discharging out the side. When heeled over, if the discharge fitting goes underwater and stays there you can get a back siphon going, no matter how high your riser, unless its got a vent at the top. Side discharge usually shows a black streak beneath it. Also, if the pump runs when the discharge is on the high side the wind can blow the bilge water back over the rail.
seo

[Ian McColgin]

T-ing into the cockpit drains has some potential traps. All too many are not correctly crossed and if the boat is heeled over the bilge pump T could easily be below waterline even if the cockpit end of the drain is a bit dry. In a good rain squall, whatever anti-syphoning protection was afforded by the cockpit drain may well be obviated anyway.

Even if T-d to the cockpit drains, I favor a good high vented loop in addition to a check valve at the pump. If you must put a through hull, try to have the discharge nice and high near the cockpit on the port side. You're more likely to bring the tender to the starboard side and there's no reason to squirt bilge water at the guests. Near the cockpit so you know what's going on. I don't favor pump discharges or even sail boat exhausts on a transom except with great care as you don't want a following sea from back flooding the bilge.

Even an above waterline through hull fitting should have a sea cock.

While pumping, there will be no dribble down the side. Assuming a good high vented loop, the discharge will end abruptly just after the pump is off with not even a little dribble. If you install a nice external flange with the through hull and maybe just a little nubbin of epoxy, the last few drops will bead off that and drop clear anyway. You'll only dribble if you have oily bilges, which you shouldn't.

G'luck

[ddeaton]

http://www.imagestation.com/picture/sraid195/p1946a75d5477ca50d15578efa67b69a1/f14094e6.jpg
This is she. Wittholz 17.
Thanks,
Danny

[ddeaton]

You bring up another good point. Should a sea cock be in series with the cockpit scuppers?
Thanks for all the info,
Danny

[Gary E]

The advice others have givin is right for a big boat...
BUT... your's is NOT...it's 17 ft...and lives on a trailer. If you need a bilge pump, FIX THE LEAK... and then use a sponge.

[Dan McCosh]

While we have successfully used a scupper-drained bilge pump for years, I would think only a through-transom discharge above the waterline would work for that boat.

[Art Read]

"Depends.......

lots of depends there."

Man wants a pump, not diapers! ;)

[Alan Peck]

ddeaton: This is off topic, but if you have any more pictures of the 17' Wittholz, I would love to see them

[Bruce Hooke]

Nice boat! Are you planning to keep her on the trailer when you are not out sailing or will she be kept at a mooring at least some of the time? If the former, then I really don't see much point in an electric bilge pump. Heck, my father's boat is kept on a mooring all summer and does not have an electric bilge pump and seems to do just fine. The one caveat is that this assumes that any rainwater that falls in the cockpit has a way to drain over the side rather than into the bilge. If rainwater will drain into the bilge then clearly water could accumulate pretty quickly in a heavy rain storm.

Bilge pumps can be useful, but they can also be a lot of trouble and your typical small bilge pump cannot keep up with anything but the smallest of leaks anyway. On an hull that leaks a bit an electric bilge pump can save you the trouble of going out occassionally to pump the bilge dry, but a boat like yours should not leak, so as long as rainwater can't get into the bilge there should not be anything to pump.

Keep in mind that a typical small bilge pump is pretty much useless in an emergency because it will not pump enough to matter. For emergency use you may therefore want a high-capacity manual pump of some sort, but on a boat the size of yours a good bucket can serve pretty well as an emergency pump!

[uncas]

Interesting since this summer started to have problems with water backwashing into the bilge through my waterline to the pump...
Currently, my thruhull is right on the waterline...Not that this matters under sail as it often is underwater...
Have come up with two possible solutions...one...a long horseshoe bend in the line from the pump to the thruhull or two...getting a secition of tubing which prohibits back flow...
This doesn't really help...but these may give you some ideas to limit the backwash should you put the thruhull on or below the waterline.

ps...am thinking of putting in a backup pump in the bilge...So appreciate the idea about putting it in line with one of the scupper's thruhulls...as opposed to piutting another hole through the hull.
Thanks
jamj

[ 11-30-2005, 10:32 AM: Message edited by: uncas ]

[Dan McCosh]

A simple U doesn't work to prevent back-siphoning. The reason is that once the pump kicks on, it fills the pipe, and then it works as a siphon. I discovered this the hard way when the outlet submerged on a long tack. The solution is a check valve at the pump. The cockpit drain acts as a siphon break, and prevents this from happening, when it is pumping through the drain--assuming the bilge pump connection is close to the cockpit floor. We use an upside-down check valve that kicks closed when the bilge pump comes on--which keeps the pump from pumping water into the cockpit.

[ 11-30-2005, 11:50 AM: Message edited by: Dan McCosh ]

[uncas]

Dan...even if the "U" is positioned in such a way as it is above the waterline? Upside down horsehoe
This was a new one for me this summer...Woke up one night and heard water coming into the boat...Pulled everything out of the lazerettes thinking something had rammed me and put a hole in Uncas...
Nope...just the hose siphoning water back in...
What about that tubing which prohibits back siphoning...?
Second idea...I know the stuff exists but don't know whether it works.

[Alan Peck]

I guess I am missing something pretty basic. But why not just discharge the bilge pump line high above the waterline? I have mine discharging about 4" below the top of the transom. That way the boat has to be almost sunk anyway before any water can back up. I wouldn't feel comfortable using a backwater valve as they often don't work when you need them to.

I don't think the discharge port looks bad. Of course there is an outboard hanging on the transom so who would notice the discharge port?

[uncas]

Alan...I really don't want to hijack this thread...not my intention....However, gotta answer your question if it was directed my way...My thruhulls are already there...right on the boot stripe...I don't want to drill another hole...for obvious reasons...Uncas turns 60 next year...Hence...want to use the thru hulls...I have.
Sorry for the hijack...really was not intentional...but ya see...I have this bilge pump problem...

[Gary E]

Originally posted by uncas:
Alan... Hence...want to use the thru hulls...I have.
but ya see...I have this bilge pump problem...So 60 yrs ago they put the holes in the wrong place and now that you know the right place you stil want to use the wrong place.

As I understand it your boat is out of the water now, so now is the time to plug those wrong holes and put in ONE high up so you will have corrected the problem forever...Next time you may not hear the water comming in.

Sorry if I sound like..."Fix it right once and it stays fixed"... but that's me.

[uncas]

GaryE...just hate drillin another hole....

[Gary E]

Originally posted by uncas:
GaryE...just hate drillin another hole....You would hate raizin it from the botom aHOLE lot more...

[uncas]

Goota a damn good point....And I would!!!!!

[Gary E]

I realize you guys with sailboats come from a different school. But water in the bilge of a powerboat means 2 things...
I GOTZ A LEAK...
and I GOT TO SPEND MORE $$$ HAULING IT AROUND...

Therefore many use more than 3 pumps... and they use a indicator light to tell them that the pump is running.

Now lets think of the sailboat with it's rather calm and peacefull movement through the water or the time when it's ruffer'n crap and you dont have time to take a leak yourself so you wizz in the cockpit (aint that why the name?) and let the water that's sloshin around wash it away...Would'nt it be nice to have some way to know that the big pump, that second one, you install just for emergency is runnin?

If there was a way to route the output line up the interior of the boat so you could put a thru hull fitting in the cabin side so the water would drop on the walk around deck, YOU WOULD SEE THAT !!! no light to watch...cuz your too buzzy looking at sails and compass. Sportfish guys have to scan the instruments all the time so a light is a eazy signal.

SO now ya see the water squirting out where ya know it should not be comming from ...NOW THAT's a WAKE UP!!!!!

[ 11-30-2005, 01:32 PM: Message edited by: Gary E ]

[paladin]

Jamie ...if'n ya dunno wanna drill the hole...I can punch it fer ya....about .50 caliber size...

[Gary E]

Or, if ya need a biga hole, I can load the dbl brl 12ga with slugs smile.gif

[uncas]

I want a hole guys...I don't want to have to replace planks....

[notwoodbut...]

Danny,

If your boat has a centerboard, an easy fix is to drain the pump into the centerboard trunk. This is pretty common on cats.
See Joe's second picture for a manual pump pic(by the way Joe, Catboat Assoc Meeting is in Newport in Feb. You gonna try to make it?)
http://www.woodenboat-ubb.com/ubb/ultimatebb.php?ubb=get_topic;f=6;t=005169 You can set it up permanently or just run a hose from the pump up and into the slot if it's exposed and the pump is more for convenience or for while you're away. Just make sure the hose is secured so you're not pumping water up and then back into the bilge if the hose comes loose.

Jim

[ 11-30-2005, 03:15 PM: Message edited by: notwoodbut... ]

[ddeaton]

She is not going to live on the trailer. She will be moored spring, summer, and fall at the local lake, as does my 14' Handycat. Which has to be watched over and drained out before I sail her. I have already put enough time and effort into her that a bilge pump would be a very minor addition. She has not seen water yet, so I dont know if she will even float. Peace of mind.

[ddeaton]

Jim,
Yes, I am going to the Catboat meeting.
Thanks,
Danny

[uncas]

Peace of mind is a very good thing...Better safe and free of worries than the opposite...

[Dan McCosh]

Re: siphoning. There is a commercial siphon break, which can be installed at the top of the "U", which lets air in and breaks the siphon., These can stick also--a friend had one that regularly did so and filled his engine with water via the water-lift muffler. Anyway, even check valves can fail. Another solution is to put a "T" fitting in the line and run a hose from this to a point high up. This acts like a siphon break as well--doing the same thing as a cockpit scupper, but without the cockpit drain. Might add I have a 1 1/2 ins. outlet hose on the bilge pump, so I'm a little touchy about back-siphoning.

[ 11-30-2005, 05:10 PM: Message edited by: Dan McCosh ]

[uncas]

Dan...that's kinda the direction I was going...at least in my mind...Should work!!!

[notwoodbut...]

Danny-

That's great. Maybe we'll touch base later re: Newport.
By the way though, is your boat a centerboarder? Looks like it in the pic. I am of the belief that that model was built with either centerboard or shallow keel. I think I looked at one about 10 years ago in Hull,MA that was equiped with the shallow keel. I understand that they don't handle quite as well as the centerboard model but that the lack of a centerboard trunk makes them alot bigger down below.
Jim

[ddeaton]

Yes, it is the centerboard version.

[seo]

"Crossing" cockpit drains has absolutely no effect. Really. To prove this to yourself, draw two identical sections of the boat right at the cockpit. Draw one with crossed drain pipes, the other with straight.
Now get a piece of plastic or something transparent, and lay it over the drawing at the waterline. The bottom of the drain is underwater, while the top is above. Doesn't backflood. Now incline the drawing (or the water) to illustrate the effect of heeling. When the downhill cockpit drain goes below the heeled waterline, the drain back floods. Doesn't matter if the drains go straight, cross, twist, turn, or dosey-do. Water seeks its own level.
The only way to prevent backflooding are: to put a riser in the drain line that will rise above the heeled waterline, but then when the hull is on an even keel the riser will still prevent water from going down the drain, until the water level in the cockpit has risen above the height of the riser. Which is good if you want a foot bath.
OR, to have the cockpit sole high enough above the waterline so that even when heeled it doesn't go below the heeled waterline.
Long explanation here of narrow heavily ballasted boats that roll down, versus wider, lighter boats that roll up. Blah, blah blah.
Or to use one of those cast-bronze cockpit fittings with a rubber ball that floated up and (in theory) sealed the fitting against backflooding.
Gravity is relentless.
seo

[Jay Greer]

Many years ago, I came up with a simple solution of curing back flow and drag problems with cockpit drain fittings. We use flush mounting through hull fittings and lay a flap of frosted drafting mylar film over it that is copper stapled to the hull on the leading edge. this is faired in with epoxy and micro balloons. The frosted film will accept bottom paint and when under sail, the back flow is prevented by water pressure on the flaps. However, if a greenie fills the cockpit, the weight of the water is enough to overcome the sealing effect of the mylar flap. Works like a charm!
JG

[Jagermeister]

Jay:

You've updated Chapelle's recommendation of oiled leather flaps to use modern materials. Of course, he didn't go so far as to fair the leading edge, but flaps are certainly a time honored method.

[ 12-01-2005, 08:47 PM: Message edited by: Jagermeister ]

[Ian McColgin]

Crossed drain lines appears to be an art lost along with the loss of lovely low shear lines. It's appropriate for cockpits that due put their lower corner below the extreem heeled waterline.

The drain leads from the lee corner (fore or aft depending upon the cockpit but most typically fore) to a through-hull that just emerges above the heeled waterline on weather side. This drain will neither admit new water nor drain cockpit water except that which is above the heeled waterline.

On a boat like Goblin, an Alden 43 that I often sailed with the gunnel under, crossed drains of this sort worked better than even a little clamshell.

But whatever.

[seo]

Ian: When the boat heels like that, lifting the uphill cockpit drain through-hull out of the water, what happens to the water in the pipe? And what happens when she pitches into a wave?
seo

[Ian McColgin]

If the drain is rightly located and if water slopping in over the leeward rail is not too swift, then the drainline and cockpit are both clear of water when that weather hole emerges.

Water that subsequently slops into the cockpit will remain there, accumulating until it's surface is above the water line, at which point it will begin spitting out the exposed through-hull.

Edited to add: Clamshells over the bilge pump throughhull depend on a bernoulli effect as the boat moves foreward. Flaps depend upon outside water pressure, working poorly if the boat is not making weigh and not at all if the boat is drifting backwards. Thus, neither is satisfactory in a boat that may be taken off-shore and occasionally hove-to.

In a perfect world, I like a cockpit so dainty and high that the drains can be straight plumbed and emerge above the waterline. I also like my bilge pump plumbed to a through hull above the water line and I still like the highest vented loop I can put in the thing. But there are boats on which those perfections are not possible.

[ 12-02-2005, 08:06 AM: Message edited by: Ian McColgin ]

[mmd]

Mr. Herreshoff knew how to build a cockpit...

Here is a couple of sections of the "Bounty" cockpit. The one on the left is when the boat is at rest; the cockpit sole is well above the load waterline and both cockpit scuppers are located for positive drainage.

The view on the left is showing the boat romping along at a thirty degree heel, rail down, lee mid-deck awash, yet the cockpit sole is still above the waterline and the lee scupper is still able to positively drain the cockpit.

"Course, this is a big, deep-draft classic yacht, not one of the modern skimming di... er, ULDB hulls popular with the go-fast crowd today. ;)

http://i32.photobucket.com/albums/d19/mmd_ns/cockpitdrains.jpg

[Andrew Craig-Bennett]

Tbis question has vexed me a good deal.

Mirelle was built with an open topped piston pump in the cockpit sole, so that the bilge water came out into the cockpit and then gurgled away through the drains.

I did not like this idea, and fitted diaphagm pumps, one in the cockpit and one below deck, which each have loops and then merge to share a common seacock in the topsides. This works well, and there are no drips staining the topsides, but the fitting is not sightly.

[Lucky Luke]

This is a queston about which I stand firm : ABOVE WL, in any case!

Two "sorts" of pumps have to be considered:

1/ The automatic, electric (usually small) bilge pump:
In marinas, where most boats winter nowaydays, if some one - usually some next berth boat keeper - notices that some boat's bilge pump works a little too often (before batteries run out...although often on permanent charge...an other danger!), he will contact port authorities, who will have a look at the boat. That happened with me a few times, and the boats were saved. How would I have noticed if the outlet had been below WL, through cockpit drains (which are the ONLY below WL outlets left open while wintering...isn't it? :rolleyes: hum!)?

2/ The big hand pump, from the cockpit:
You will rarely use it, hopefully, and an outlet above WL will not leave strains on the hull...and who would care in those conditions?
It is, of course, out of question to have a dedicated below WL fitting for that purpose, with the inherent risks (same for the automatic pumps).
Joining this one to cockpit drains is no good eiher, since you may just back-flush into the cockpit, whatever arrangement you have: sea is seldom dead flat like Michael's computer (and mine) like to draw it ;) , ands even tends to go over cockpit coamings!. Nice to have bilge water, complete with bits of paper, some oil, a rotten salad and that beloved rag your daughter thought you had thrown overboard, all floating in the cockpit, ain't it, Andrew? :D !

So: above waterline dedicated outlets for both automatic and hand pumps! In all cases!

One option for the big pump however, specially on a nice small boat like this one: since that pump must be easily accessible from the cockpit, and fitted in one of the cockpit's lockers, is to have a loose flexible, ready with some chock-chord, that you just install to discharge oveboard when using the pump. No thru hull fitting this way. Problem is to leave the cockpit locker open, even partially.

I will do, while at it, some other comments.

One is about buckets. They are VERY efficient...and absolutely exhausting to use! Plunging it in the bilge, hoisting it up to the cockpit (and splashing yourself with it's content), and bending down and straightening up and...whaouh! This sort of legend must be stopped! While you MUST have one or more of these, and they can come handy in a real emergency, do NOT cancel your big bilge pump. You will remain efficienttly pumping for hours, (after having blocked you leak as much as possible), and still sailing your boat to a safe place - hopefully.

An other remark concerns the rubber impeller bilge pumps coupled with the engine raw water cooling pump which some engine manufacturers propose. There is a little hole between those two pumps, so that some water keeps lubricating the bilge pump while thez engine is running and the bilge dry.
The water intake of the cooling pump is, of course, below water, and the bilge intake is fitted with a non-return valve...non fully proof, usually!. Then, if you had just pumped out some bilge water and stopped the engine just after, and both impellers happen to have stopped in such a position that they leave some water flow from one pump into the other....you will be nicely siphoning the sea into your bilge through the not fully waterproof "non-return" valve! And sometimes it will happen, and sometimes not. confusing! Don't laugh: I found this fault more than once, and I'm convinced that some boats sank in harbor because of that defect!
The remedy if you have such an installation? very simple: a small anti siphoning hole in the bilge intake pipe.

Last is about where the outlets af various pipes must be placed: in the boot-top painting my dears! They would be hardly visible there...unless you have a dark hull and white boot-top...hum :rolleyes: !

[ 12-02-2005, 11:01 PM: Message edited by: Lucky Luke ]

[Roger Cumming]

Edson used to make (maybe they still do) a big bronze diaphragm pump mounted on a board. You put it on the cockpit floor, put the intake hose into the bilge and the discharge hose overboard, inserted the steel rod handle and pumped away. Your foot on the board steadied the pump as you stroked the handle. No through hull fitting necessary. Alternatively you could mount it under the deck convenient to the helm with a removable plate in the deck for inserting the handle. The discharge hose could be put overboard when you needed to pump, and stowed when not in use.

[uncas]

Okay...I just took the original bilge pump outta Uncas...Huge thing...3.5 feet...Brass...has the original hose...or what I didn't cut off to get it out...on it.
Needs to be cleaned up so...at the moment, don't know the make....But...Am thinking of having it refurbished...
I know...not having the make real handy may make this request difficult to answer..but...I'd thought I ask anyway...Any company out there refurbish old bilge pumps?
It might just need a bit of new leather...and a bit of polish...I don't know.
So...lookin at a pump circa...1948...

Also....electric pumps..I have been using Ruhls but am beginning to have trouble with them. Should have had an a warning when their five yr. warrenty....was eliminated..
So, if one is looking at electric pumps...check some other sources.

[ 12-03-2005, 08:04 AM: Message edited by: uncas ]

[ion barnes]

There is math issue here that has not been discussed, and that is the height from the pump to the thru-hull. The higher you raise the discharge the less efficient the pump becomes, and despite that I would want the discharge well above the waterline. Perhaps thru the transom? Or the centerboard box as has been suggested.

[Lucky Luke]

Originally posted by ion barnes:
There is math issue here that has not been discussed, and that is the height from the pump to the thru-hull. Much more important is the height from the bottom of the bilge to the pump: some back pressure to the pump is not too bothering...a pump that has difficulties to prime is far worse!

[Ian McColgin]

I agree with Luke. All pumps push better than they lift and bilges are rarely all that deep anyway.

The biggest lift I ever was involved with was an ancient plank on edge cutter where the bottom of the bilge was a solid 6' below waterline. I helped build a simple tube and plunger pump that had outlet pipes both ways just under the bridge deck. It was theoretically possible to make a roughly 10' stroke as the bottom of the rod and its leather cup went right to the bottom flapper valve. In reality a nice motion about a foot or so up and down got the water moving out just fine. One very nice feature was the allignment of the exit ports and the discharge pipes was just an abutment. Sure some leaked back to the bilge but it made the unit dirt simple for lifting out if the lower flapper or strum box needed clearing.

KISS.