Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 02-09-2021, 17:49   #1
Registered User
 
niftyc's Avatar

Join Date: Feb 2021
Posts: 19
Unhappy I beg you to critique my bilge pump outlet line-- it's siphoning

I bought an unusual custom 63' steel trawler that is a fixer-upper. Since everything is custom, figuring out the systems is quite a puzzle.

A leak somewhere in the engine room had me stumped. I've been laying toilet paper traps and I even considered dye. Finally it dawned on me that the bilge pump itself is the source of the water. I thought it was a little bit of backflow from the outflow line but now I see it is far more water than can be in the outlet line itself.

I've read the threads on here about plumbing bilge pump outlets. I'm thinking this isn't the correct way to do it. Here's what I've got:



The outlet line is below the waterline (marked in image as a horizontal blue line) and I believe the line is siphoning. It looks like the line has a one-way valve that has failed and is now leaking, and it has no anti-siphon valve. The outlet is to starboard. The line leads to a Rule 3700 submersible pump that is wired to operate ONLY automatically via float switch. There is no other bilge pump in this compartment.

How should I fix this if I do not move the through-hull? (e.g. it remains below the waterline?) A mechanic wants me to just replace the ball valve.

P.S.
I really appreciate the generosity of people on this forum who volunteer to help new owners like me. I don't know anything about plumbing and I'm trying to learn fast.
niftyc is offline   Reply With Quote
Old 02-09-2021, 17:55   #2
Registered User
 
Sailmonkey's Avatar

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 9,253
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

I would put a siphon break at the top of the loop. Being steel you can just drill and tap the pipe to accept something like this.

https://marinesan.com/vacuum-breaker...MaAi1gEALw_wcB
Sailmonkey is offline   Reply With Quote
Old 02-09-2021, 18:10   #3
Registered User

Join Date: Dec 2020
Posts: 750
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

If your outlet is below the waterline it MUST have a siphon break. Otherwise it will... siphon the ocean back into the boat until the bilge pump fails and the boat sinks.

I hope the rest of the boat was built with better understanding of the ocean then your bilge pump system.
BillKny is offline   Reply With Quote
Old 02-09-2021, 18:26   #4
Registered User
 
Uncle Bob's Avatar

Join Date: May 2010
Location: Sydney Australia
Boat: Fisher pilothouse sloop 32'
Posts: 2,589
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

Quote:
Originally Posted by Sailmonkey View Post
I would put a siphon break at the top of the loop. Being steel you can just drill and tap the pipe to accept something like this.

https://marinesan.com/vacuum-breaker...MaAi1gEALw_wcB
Only if the loop is significantly above the waterline, if not you should make it so.
__________________
Rob aka Uncle Bob Sydney Australia.

Life is 10% the cards you are dealt, 90% how you play em
Uncle Bob is offline   Reply With Quote
Old 03-09-2021, 09:00   #5
Registered User
 
Madehn's Avatar

Join Date: Nov 2014
Location: Kemah Tx
Boat: Gulfstar 51
Posts: 323
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

It needs to 3 feet higher than waterline in my opinion. Your mechanic doesn’t have a clue if he thought a new ball valve was sufficient. Might be a good mechanic but I wouldn’t be taking any advice from him on anything but engines
Madehn is offline   Reply With Quote
Old 03-09-2021, 09:35   #6
Registered User

Join Date: Nov 2017
Location: Portland, Oregon USA
Boat: Island Packet, Packet Cat 35
Posts: 767
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

Anti siphon valve is an easy fix. Get a bronze one. You must be able to take it apart and clean it. 3' above waterline, absolutely.

Better yet, next haulout remove the ball valve (which every through hull should have) and have that hole repaired. Move the exit point to above water.
Cpt Mark is offline   Reply With Quote
Old 03-09-2021, 12:11   #7
Registered User
 
Cadence's Avatar

Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 9,972
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

Not trying to be cute but i hope the rest of the "custom" is better than that. Move the discharge to above the waterline.
Cadence is offline   Reply With Quote
Old 03-09-2021, 13:36   #8
Registered User

Join Date: Jul 2012
Location: North East USA
Boat: 1975 Tartan 41'
Posts: 895
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

Quote:
Originally Posted by Madehn View Post
It needs to 3 feet higher than waterline in my opinion. Your mechanic doesn’t have a clue if he thought a new ball valve was sufficient. Might be a good mechanic but I wouldn’t be taking any advice from him on anything but engines
the siphon loop itself doesn't have to be 3 ft higher than waterline. he can run the air break in a tube up higher if needed, with the loop as is.. not ideal but.... but I agree that a siphon break is needed.
zstine is offline   Reply With Quote
Old 03-09-2021, 14:08   #9
Registered User
 
Nord Sal's Avatar

Join Date: Sep 2014
Location: POW Alaska
Boat: Trlåren, Saltjö Dunväs, Sweden
Posts: 240
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

Quote:
Originally Posted by Cadence View Post
Move the discharge to above the waterline.
I agree with this. Why put another hole below the waterline when you don't have to? Why depend on a siphon break when you don't have to?
Nord Sal is online now   Reply With Quote
Old 04-09-2021, 02:07   #10
Registered User

Join Date: Jan 2020
Location: Sweden
Boat: Swan 57
Posts: 133
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

Please start by studying thru-hull fittings, make sure they are made from bronze (not some kind of brass which is not uncommon), both the thru hull fitting and the valve. Hose up with a u-turn, as far as possible from the waterline, on which there is a siphon breaker (essentially a check valve letting air in but not water out when pumping) and down to the pump.
Sometimes the boat heals so that water reaches the gunwale, The U-turn should in this situation be above the water level. If not, the check valve on the pump-hose is needed but that is a compromise since crud will deposit on the check valve and it will start leaking, which is what you experience now.
Hermia II is offline   Reply With Quote
Old 05-09-2021, 06:59   #11
Registered User
 
niftyc's Avatar

Join Date: Feb 2021
Posts: 19
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

I really appreciate all the help.

Hermia, as far as I can tell there is no through hull fitting, it is a straight pipe welded to the hull with what looks to me to be a standard plumbing valve that you would find on a pipe placed a few inches in. I can try to take a better picture when I'm out at the boat.

Thanks to everyone for the advice, I wonder if anyone had thoughts about the pipe material. The metal pipe turns to a flexible line just out of view. I think they used the wrong kind of flex line. The bilge has had diesel in it at some point and it seems like diesel has dissolved the flex line -- black clumps are coming off it. Or anyhow that is my speculation as to what has happened. (There is no diesel in there now.)
niftyc is offline   Reply With Quote
Old 05-09-2021, 08:11   #12
Registered User

Join Date: Jan 2020
Location: Sweden
Boat: Swan 57
Posts: 133
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

If you use laminated PVC hose, it will do fine with contaminants like diesel as well. Don't keep the old flexible tubing if you don't trust it 100%
Hermia II is offline   Reply With Quote
Old 05-09-2021, 10:24   #13
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 2,317
Images: 1
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

some sources and info. cheers/Len


https://www.defender.com/category.js...243574&path=-1


https://www.defender.com/category.js...574&id=2243585


https://marinehowto.com/
__________________
My personal experience & humble opinions-feel free to ignore both
.
deblen is offline   Reply With Quote
Old 05-09-2021, 10:38   #14
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Helsinki (Summer); Cruising the Baltic Sea this year!
Boat: Cutter-Rigged Moody 54
Posts: 31,829
Re: I beg you to critique my bilge pump outlet line-- it's siphoning

I wouldn't have galvanized steel piping or fittings on any boat used in salt water. It rots from the inside out and will fail at the worst possible moment, perhaps sinking your boat.

Plumb that with good plastic hose to an above the waterline through hull, with a loop far above the waterline and a syphon break.
__________________
"Parce que je suis heureux en mer, et peut-être pour sauver mon ame. . . "
Dockhead is offline   Reply With Quote
Reply

Tags
bilge, bilge pump, pump

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Jabsco Quiet flush back siphoning Capt. Aubrey Plumbing Systems and Fixtures 8 20-02-2016 08:10
Bilge pump outlet issue wiekeith Plumbing Systems and Fixtures 11 06-09-2015 09:32
Beg, borrow, buy CHARTs Dbl07 General Sailing Forum 11 15-02-2013 17:12
Head Is Siphoning . . . Not Mine, My Boat's sailstoo Plumbing Systems and Fixtures 2 01-11-2011 16:32
Water Heater Siphoning Through Engine RussR Plumbing Systems and Fixtures 9 13-09-2011 15:14

Advertise Here


All times are GMT -7. The time now is 17:30.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.