Bilge Pump siphoning water BACK into boat - 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 > General Interest > General Discussion (sailing related)
 Not a Member? 


Reply
 
LinkBack Thread Tools
  #1  
Old 10-19-2010
Junior Member
 
Join Date: Jul 2009
Location: Chicago, IL
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
windtraveler is on a distinguished road
Bilge Pump siphoning water BACK into boat

Hey everyone - I have been poking around on and I cannot find a post that relates to exactly our issue, so I will post it here (I apologize in advance if there is already a discussion).

Here is our issue - our automatic bilge pump, we discovered - is siphoning water back into our bilge when we are under power (and when the butt of the boat goes down)...it was a very "un-fun" discovery that you can read about here: Windtraveler: Taking on Water is NOT Fun...

Anyway - we already have an anti-siphon right at the bilge - about 3 feet from the bilge pump itself. We also have a loop in a lazarette, but obviously this is not enough...we think when we are butt down and motoring at 6+ knots, there pressure building over the course of the hose and then, filling the bilge...

Should we add another anti siphon closer to the back of our boat, by where the bilge exits the boat? Or is there something else we should do?

Thanks in advance!

Best,
Brittany (& Scott)
__________________
Free is the heart that lives not in fear.
Follow us as we journey around the world!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 10-19-2010
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 11 Times in 11 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 anti siphon loop and siphon break needs to be as high up in the bilge pump output hose as possible, and definitely above the waterline on both tacks...

If the anti-siphon device is below the waterline or at a lower point in the hose, it won't break the vacuum and stop the hose from siphoning.
__________________
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.

Last edited by sailingdog; 10-19-2010 at 01:56 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 10-19-2010
Junior Member
 
Join Date: Jul 2009
Location: Chicago, IL
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
windtraveler is on a distinguished road
Thanks Sailing dog, yes, the loop is high enough...but what about the antispihon valve? Should that be somewhere specific? Right now it is about 3 feet above the bilge pump itself, and we are wondering if we should move it somewhere else? Thanks again.
__________________
Free is the heart that lives not in fear.
Follow us as we journey around the world!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 10-19-2010
erps's Avatar
the pointy end is the bow
 
Join Date: Aug 2006
Location: La Conner, Washington
Posts: 6,221
Thanks: 2
Thanked 26 Times in 26 Posts
Rep Power: 10
erps will become famous soon enough erps will become famous soon enough
It should be at the top of the loop.
__________________
Ray
S.V. Nikko
1983 Fraser 41
La Conner, WA


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


Boating for over 25 years, some of them successfully.
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 10-19-2010
RichH's Avatar
Senior Member
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 2,975
Thanks: 10
Thanked 90 Times in 82 Posts
Rep Power: 15
RichH will become famous soon enough
Repeat of what 'dog posted: the siphon breaker MUST be at the *very highest* part of the discharge line AND the height of the 'loop' must be 'well above' the highest heeling angle so that siphon break stays ABOVE the heeled water line.
Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 10-19-2010
Junior Member
 
Join Date: Jul 2009
Location: Chicago, IL
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
windtraveler is on a distinguished road
Okay, thanks everyone...does anyone see any issue with putting two in...one at the top of the loop, and one where the original is (near the bilge) to prevent more backflow?

Thanks!
__________________
Free is the heart that lives not in fear.
Follow us as we journey around the world!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 10-19-2010
Junior Member
 
Join Date: Jul 2009
Location: Chicago, IL
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
windtraveler is on a distinguished road
To clarify, two VALVES, not loops....one valve at the top of the loop, one nearer the bilge pump itself...

Thanks!
__________________
Free is the heart that lives not in fear.
Follow us as we journey around the world!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 10-19-2010
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 11 Times in 11 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
To clarify: If the anti-siphon valve is not at the very highest point of the line, at the top of the highest loop, water pouring down the hose into it will close the valve, just like the pressure of water coming up from the pump does... It won't be at a point where the water in the hose is only generating a siphon vacuum, so it won't work properly.

I would remove the lower one. It becomes another point of failure, and you really want to reduce those in a bilge pump. It also probably adds more friction to the output hose and reduces the amount of water the pump can move. What you should do is have a continuous, smooth run from the output barb on the pump to the inside part of the siphon break at the highest point the hose runs. Use a smooth wall hose to reduce the resistance to the 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.

Last edited by sailingdog; 10-19-2010 at 02:00 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 10-19-2010
JohnRPollard's Avatar
Moderator
 
Join Date: Mar 2007
Location: Chesapeake
Posts: 5,680
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 10
JohnRPollard is a jewel in the rough JohnRPollard is a jewel in the rough JohnRPollard is a jewel in the rough
It sounds to me like the O.P. may actually haver a check-valve in place, not two anti-siphon valves.

If this is your one and only, or primary bilge pump, I would get rid of the check valve.

As for the reason why water is siphoning back into the boat, I would suspect that your anti-siphon valve is gunked up with salt or other deposits and is not functioning properly. I.e., it is no longer open and therefor isn't breaking the siphon. You should at least confirm that it's working properly.
__________________

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

Pacific Seacraft Crealock 31 #62

NEVER CALLS CRUISINGDAD BACK....CAN"T TAKE THE ACCENT
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 10-19-2010
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 11 Times in 11 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
From his description, he only has one of whatever he has, and if it is a check valve, it ain't working properly. Granted, he really shouldn't have a check valve in the bilge pump line, and he should have an anti-siphon valve in it...

Quote:
Originally Posted by JohnRPollard View Post
It sounds to me like the O.P. may actually haver a check-valve in place, not two anti-siphon valves.

If this is your one and only, or primary bilge pump, I would get rid of the check valve.

As for the reason why water is siphoning back into the boat, I would suspect that your anti-siphon valve is gunked up with salt or other deposits and is not functioning properly. I.e., it is no longer open and therefor isn't breaking the siphon. You should at least confirm that it's working properly.
__________________
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 Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




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
Bilge pump that leaves very little water available? jarcher Gear & Maintenance 10 06-21-2010 08:19 PM
Installing automatic bilge pump in series with diaphram bilge pump... sweetdreamyamaha Gear & Maintenance 6 11-07-2009 12:36 PM
Shallow Bilge, Bilge Pump Switch labestia Gear & Maintenance 1 07-10-2009 03:40 PM
Bilge pump dump below water line boydgatlin Sailboat Design and Construction 5 07-06-2009 12:20 PM
Bilge Pump Failed, 6" Water over floor, what now? psolson Gear & Maintenance 33 09-07-2006 05:26 PM


All times are GMT -4. The time now is 12:47 AM.

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.