Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 25-09-2012, 01:22   #1
Registered User
 
Shanaro's Avatar

Join Date: May 2012
Location: NZ
Boat: Marauder 8.4
Posts: 5
Bilge Pump questions

Hi all, I am going to install an automatic Bilge Pump in our 28 foot yacht. Please share your thoughts on what would be a sensible size pump to use. IE how many GPH would suit this size vessel? Is there a formula or basic rule of thumb to follow? I know some will likely say the bigger the better but the physical size of some of the extra large pumps could obviously be a drawback. Also your opinions on where the outlet should be located.
__________________

__________________
Shanaro is offline   Reply With Quote
Old 25-09-2012, 01:36   #2
Registered User
 
boris's Avatar

Join Date: Sep 2007
Boat: warwick 44
Posts: 108
Re: Bilge Pump questions

Biggest is best as it gives you more time to sort a patch/repair

Unless you are just wanting to remove a little rain water from the bilge
__________________

__________________
boris is offline   Reply With Quote
Old 25-09-2012, 02:14   #3
Moderator
 
carstenb's Avatar

Cruisers Forum Supporter

Join Date: May 2012
Location: Copenhagen
Boat: Jeanneau Sun Fast 40.3
Posts: 4,939
Images: 1
Re: Bilge Pump questions

The bigger the better. But you noted automatic so you need to switch it off when you're not around, if rainwater or the like have ingress to the bilge. It will drain the batteries quickly if there is any water.
__________________
I spent most of my money on Booze, Broads and Boats. The rest I wasted - Elmore Leonard
carstenb is offline   Reply With Quote
Old 25-09-2012, 02:27   #4
Registered User
 
Shanaro's Avatar

Join Date: May 2012
Location: NZ
Boat: Marauder 8.4
Posts: 5
Re: Bilge Pump questions

Thanks guys, my intention is to leave it on auto when not on board. The boat is often unattended for several weeks.
__________________
Shanaro is offline   Reply With Quote
Old 25-09-2012, 02:34   #5
Moderator
 
carstenb's Avatar

Cruisers Forum Supporter

Join Date: May 2012
Location: Copenhagen
Boat: Jeanneau Sun Fast 40.3
Posts: 4,939
Images: 1
Re: Bilge Pump questions

Then you need to be sure there is no ingress of water (like rainwater). Otherwise the batteries will run flat.

On the other hand, if you end up with a hole in the boat (say hose pops off and ball valve is open) and you're not around for several weeks, the pump will not help you. It will pump until the batteries run dry, then the boat will sink.
__________________
I spent most of my money on Booze, Broads and Boats. The rest I wasted - Elmore Leonard
carstenb is offline   Reply With Quote
Old 25-09-2012, 02:56   #6
Moderator
 
Hudson Force's Avatar

Cruisers Forum Supporter

Join Date: Nov 2008
Location: Lived aboard & cruised for 45 years,- now on a chair in my walk-in closet.
Boat: Morgan OI 413 1973 - Aythya
Posts: 7,894
Images: 1
Re: Bilge Pump questions

Quote:
Originally Posted by Shanaro View Post
.............. Also your opinions on where the outlet should be located.
Many choose to have the outlet well above the waterline. This would lessen the chance of water entering the effluent, but usually results in an ugly stain running down the freeboard. Many have the effluent in the boot stripe just an inch or two above the waterline, but at this location an anti-siphon loop is essential. Without the anti-siphon loop each time the vessel rocks it can take in a sip of water and this can add up quickly.
__________________
Take care and joy, Aythya crew
Hudson Force is offline   Reply With Quote
Old 25-09-2012, 05:14   #7
Registered User
 
Snowpetrel's Avatar

Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,071
Re: Bilge Pump questions

Ideally put the outlet up high and toward the center of the transom, No chance then of the thing siphoning back when you are heeled over hard. If there is any possibility that the outlet may be underwater when you are sailing hard don't put complete trust in siphon breakers or non return valves. Fit a valve somewhere in the system just in case.
__________________
My Ramblings
Snowpetrel is online now   Reply With Quote
Old 25-09-2012, 05:48   #8
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,580
Images: 240
Re: Bilge Pump questions

ABYC Standard H-22 (Electric Bilge Pump Systems) requires that Bilge Pump Discharges be located above the maximum heeled waterline; or have (both) a seacock and vented anti-siphon loop (not a check valve).
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 25-09-2012, 07:48   #9
Registered User

Join Date: Aug 2009
Location: Hudson Valley N.Y.
Boat: contessa 32
Posts: 826
Re: Bilge Pump questions

Manuals always work if your arms are still all attached.I understand the argument for el pump when not aboard but one does not then readily know if any of the inevitable leaks are increasing/decreasing or if its rain water, plumbing, or sea water, melting ice water from leaky ice chest ,etc etc..If one really wants to know what is going on with their craft a manual pump is another way to take the pulse of your ship.
Easy for me to say since I have a smaller boat and have thereby developed bigger biceps along with greater understanding.
__________________
mrohr is offline   Reply With Quote
Old 25-09-2012, 07:58   #10
Moderator Emeritus
 
Ex-Calif's Avatar

Cruisers Forum Supporter

Join Date: May 2007
Location: Singapore
Boat: Maxi 77 - Relax Lah!
Posts: 11,514
Images: 4
Re: Bilge Pump questions

I have a 500 gph pump. You may consider 800 gph. It is wired to the house. The house is 140 a/h and topped up by solar.

You won't save a boat with batteries and a bilge pump from a catastrophic failure.

My outlet is pretty much as Gord describes.
__________________
Relax Lah! is For Sale <--- Click
Click--> Custom CF Google Search or CF Rules
You're gonna need a bigger boat... - Martin Brody
Ex-Calif is offline   Reply With Quote
Old 25-09-2012, 08:02   #11
Registered User

Join Date: Dec 2008
Location: Oriental, NC
Boat: Mainship Pilot 34
Posts: 1,429
Re: Bilge Pump questions

A better setup is to have a smallish bilge pump mounted low and a larger one- 1000 gph or bigger, with its switch mounted a few inches higher than the smaller one.

David
__________________
djmarchand is offline   Reply With Quote
Old 25-09-2012, 08:32   #12
Sponsoring Vendor
 
HopCar's Avatar

Community Sponsor
Cruisers Forum Supporter

Join Date: May 2011
Location: Miami Florida
Boat: Ellis Flybridge 28
Posts: 3,160
Re: Bilge Pump questions

I vote with David on this. Install two pumps. One small and as low in the bilge as possible and one larger a few inches higher than the small pump. The problem with mounting large pumps in a small bilge is that the discharge hose can hold enough water to cause the big pump to cycle on and off endlessly. With luck the large pump will never come on.
__________________
Hopkins-Carter Marine Supplies & Fishing Tackle
What You Need, at the Price You Want...with Service!
HopCar is offline   Reply With Quote
Old 25-09-2012, 08:34   #13
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2006
Posts: 1,594
Re: Bilge Pump questions

I caution against using the drop in centrifugal pumps unless your bilge is and will stay spotless. The impeller will jam on virtually anything. Hair, slivers of wood, piece of caulk, etc. and render it useless After having my Rule 1500 not function too many times, I switched to a remote mounted diaphragm pump. Mines a jabsco pump mounted in a cockpit locker. In the bilge is a strum box with built in one way valve and an electronic water detection switch. Five years and it's not needed to be touched.. It will suck up marbles and spit them out the transom. The outlet should be well above the waterline...

The system I described is NOT cheap, but then neither is my Cape Dory, haha..
__________________
Randy

Cape Dory 25D Seraph
rtbates is offline   Reply With Quote
Old 25-09-2012, 08:58   #14
Moderator... short for Cat Wrangler
 
sarafina's Avatar

Cruisers Forum Supporter

Join Date: Jul 2009
Location: San Francisco
Boat: Cal 28 Flush Deck
Posts: 5,559
Images: 56
Re: Bilge Pump questions

I like a couple of things that keep it working. Install the pump in a sieve that keeps the chunky stuff away. 1/4 inch hardware cloth works well. Big enough to allow the free flow of water , but fine enough to keep what would choke the pump from getting thru.

The idea, that I have not used yet but plan on, is installing a float switch higher by a bit than the pump and putting a float on it that reaches down to the pump level. In the past the switch has been the weakest link in the chain. This way it will be up out of anything that might muck it up.
__________________
Sara

ain't what ya do, it's the way that ya do it...
sarafina is offline   Reply With Quote
Old 25-09-2012, 11:09   #15
Senior Cruiser

Cruisers Forum Supporter

Join Date: Dec 2006
Location: Seattle
Boat: Cal 40
Posts: 2,401
Images: 7
Re: Bilge Pump questions

There's at least 2 different problems being addressed. One is a catastrophic hole, the other is maintenance.

Catastrophic, you want the biggest pump you can fit. One surveyor points out it takes a lot less water to sink a small boat than a big one. As others have pointed out if you're not at the boat or have an alarm that someone will do something about, a big pump won't do any good. A diaphragm pump isn't big enough for this use.

For small amounts of water a maintenance pump can be small. A diaphragm pump will pump air and water, potentially making for a dryer bilge and it has 2 check valves in it, less worries about backflow. If you go with centrifugal you want a small pump as all the water in the hose will drain back into the bilge, so smaller pump, smaller hose, less water remaining in bilge when pump turns off.

I also like the 2 pump idea, I have a diaphragm pump for my deck leaks and a big centrifugal mounted higher for sinking.

You want an hour meter on the pump to let you know if leaks are getting worse while you're away.

One argument against mounting the outlet as high as possible is pressure head is determined by the difference in height from the inlet to outlet. A centrifugal pump's output is affected by pressure head. It is not determined by the highest point of the hose.

How big is big
Another Bilge Pump Thread
__________________

__________________
cal40john is offline   Reply With Quote
Reply

Tags
bilge, bilge pump

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 14:34.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.