Redundant bilge pump - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 12-30-2007
teshannon's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Philadelphia
Posts: 2,713
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
teshannon has a spectacular aura about teshannon has a spectacular aura about teshannon has a spectacular aura about
Redundant bilge pump

My electric bilge pump has a manual back up. I'm considering adding a completely redundant electric bilge pump. I'm thinking of a second bilge pump, switch, strainer and suction hose tied into the existing discharge. I'm wondering how many people out there have such an arrangement or is it overkill?
Reply With Quote Share with Facebook
  #2  
Old 12-30-2007
Freesail99's Avatar
Senior Member
 
Join Date: Feb 2006
Location: New Jersey
Posts: 4,507
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
Freesail99 will become famous soon enough
Send a message via Yahoo to Freesail99
I have 2 one is near the engine and the other is mid ship. It doesn't cost a lot to do. I used a T fitting to tie in to the existing hose.
__________________
S/V Scheherazade
-----------------------
I had a dream, I was sailing, I was happy, I was even smiling. Then I looked down and saw that I was on a multi-hull and woke up suddenly in a cold sweat.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
  #3  
Old 12-30-2007
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 9 Times in 9 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
I wouldn't plumb it into the existing discharge, unless you have some sort of high loop in the line going to each pump. Otherwise, the water could easily back up and then flow back into the bilge via the other hose and pump. You could also use a check valve in each line, but I'm not a big fan of check valves since they reduce the pump's output somewhat.

Having multiple electric bilge pumps is usually a good idea. My preferred setup is having two separate switches and two outlets....with the one switch set as low as possible and the second a few inches higher than the first.

The first switch is connected to a very small pump, with a narrow hose. This is the "maintenance" pump, and keeps the bilge dry of any water that occurs as the result of normal operation of the boat, including drips from the stuffing box and such. The smaller pump and hose reduce the electrical load and how much water can back flush in to the bilge when the pump shuts off. This one has a bilge pump counter on it... so the rate of leakage over time can be checked.

The second pump is a much higher capacity pump with a much larger diameter hose. This is the "emergency" bilge pump and is for helping deal with larger leaks. This pump should have redundant backups IMHO, including, ideally, two manual ones—one in the cabin of the boat, and one operable from the cockpit of the boat.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #4  
Old 12-30-2007
Wayne25's Avatar
Senior Member
 
Join Date: Jul 2006
Posts: 378
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 9
Wayne25 is on a distinguished road
Its a good idea. I have 3 on my boat. However, using a common discharge would require the use of check valves to stop pumping back into the standby pump. That's a bad idea. Bilge pumps loose pumping capacity quickly with just a small amout of added pumping resistance, known as head or pressure drop. Install a separate discharge hose and fitting.
Reply With Quote Share with Facebook
  #5  
Old 12-30-2007
Junior Member
 
Join Date: Jun 2007
Posts: 13
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
centralFLsailor is on a distinguished road
Coincidently, today I was attempting to install a second bilge pump and tried plumbing the discharge into the drain of my sink bit I found out real fast that this was not a good idea. The discharge was under the waterline and siphoned back in. I'm now looking for an alternate solution. Where do you suggest plumbing the extra bilge pump?

Kevin
Reply With Quote Share with Facebook
  #6  
Old 12-31-2007
jrd22's Avatar
Courtney the Dancer
 
Join Date: Nov 2000
Location: San Juan Islands., WA, USA
Posts: 3,813
Thanks: 3
Thanked 14 Times in 14 Posts
Rep Power: 14
jrd22 will become famous soon enough
I think it makes a lot of sense, our new boat has three bilge pumps. We have two electric and one manual. There are any number of reasons for a bilge pump to not operate correctly when you really need it, so a redundant electric makes a lot of sense to me. The manual is the last resort if all else fails. One electric is plumbed through the manual's discharge which I am not sure is a good idea, but seems to work fine. I think I am going to plumb it with it's own discharge to reduce any flow restriction(long way down on major refit list).

John
__________________
John
SV Laurie Anne

1988 Brewer 40 Pilothouse

Reply With Quote Share with Facebook
  #7  
Old 12-31-2007
Sasha_V's Avatar
Senior Member
 
Join Date: Feb 2004
Posts: 459
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
Sasha_V will become famous soon enough
Redundancy is good when it comes to keeping the wet stuff outside.

Consider a different kind of pump, though. I liek staged pumps. Stage one is a standard little impellor pump form a generic marine store. Set 20mm in the bilge higher is an electrical diaphram pump that pushes way more water, has its own float switch and can cope with larger particles in the water that would clog the little impellor pump...Scale up through as many pumps as you see neccassary.

Simply duplicating impellor pumps is not the best option. If the first one clogs due to stuff in the bilges...the second one will about ten seconds later, and then what is the point?

Think in terms of if X kills pump A, what sort of pump do I need so it won't die too.

Sasha
Reply With Quote Share with Facebook
  #8  
Old 12-31-2007
chef2sail's Avatar
Senior Member
 
Join Date: Nov 2007
Location: Maryland
Posts: 6,832
Thanks: 28
Thanked 54 Times in 50 Posts
Rep Power: 7
chef2sail will become famous soon enough
Send a message via AIM to chef2sail
Wink

We have 2 seperate electric and one manual They have seperate discharges.

You might also want to consider this. I attached a brass fitting to the thru hull which draws the raw water to my engine. ( I have a FWC engine with raw water exchanger.

This fitting is "T" ed to 1) the hose to the raw water pump to the engine and 2) a separate threaded opening which I have put a threaded plug in. I have a 10 foot length of hose in my spare parts attached by c claps to a barb with the other end threaded which can be screwed into the "T" fitting after pulling the threaded plug out.

This arrangement allows me to easily winterize my engine for one but also serves as an emergency "bilge system" which if necessary would allow me to use the engine raw water pump to pump out the bilge by simply sticking the hose in the bilge after attaching to the "T" fitting. This is a redundancy of bilge pumping which does not necessarily rely on the electrical system

Dave
Reply With Quote Share with Facebook
  #9  
Old 12-31-2007
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 9 Times in 9 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
The one caveat I have for the engine cooling line as a dewatering device is that doing so can easily make a bad situation worse... You're much better off IMHO putting in several electric larger high-capacity diagphragm pumps and not futzing with the engine cooling system. If you futz with the engine cooling system, you might get debris in it...that would cause it to stop working properly—and that would kill the engine just when you may need it most.

Also, most engine cooling systems don't draw all that much water...so they aren't really all that useful as a dewatering pump.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #10  
Old 12-31-2007
Sasha_V's Avatar
Senior Member
 
Join Date: Feb 2004
Posts: 459
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
Sasha_V will become famous soon enough
Completly agree with the above DO NOT USE YOUR ENGINE RAW WATER INTAKE ASA BILGE PUMP! You will move very little water even if it works perfectly. You will endanger your engine to a perilous degree when you need it most, and the impellor will really only take up water if it is primed or at positive pressure...Which means you need to artifically inject water into the hose to get it going, or the engine has to be half submerged by the water in the bilges before it works. All this for less then ten gallons PER HOUR on most 20HP engines.

Running your engine when you need serious bilge pumping is a good idea. It keeps your batteries charged when you are using electric pumps and if you are smart and worried about such possibilities you can fit a high volume pump running off a pulley on your engine which can be engaged at will. This will move up to 3000gallons per hour and will not much care if it sucks up a cat by way of debris....

But trying to make the very small engine coolent pump drain your boat is nine kinds of stupid.
Oh yeah...the other advantage of running the engine in those circumstances...It improves your chances of running for shore somewhere!

Nothing beats solving the mystery hunt for the big hole around the bits of yacht interior you can check, like getting to a travel lift, dock with serious craneage or even a soft gradual sandy beach. Then you can check theproblem from the outside (You'll find it, water from your bilges will be pouring out of the hole!)


Sasha
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Devising a Better Bilge Pump Don Casey Seamanship Articles 0 06-02-2002 08:00 PM
Devising a Better Bilge Pump Don Casey Gear and Maintenance Articles 0 06-02-2002 08:00 PM
Devising a Better Bilge Pump Don Casey Cruising Articles 0 06-02-2002 08:00 PM


All times are GMT -4. The time now is 04:21 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.