Reply
 
Thread Tools Search this Thread Display Modes
 
Old 10-26-2020, 07:19 AM   #1
Member
 
City: Lathrup Village
Join Date: Sep 2019
Posts: 6
Check valves between water tanks

I'm in the process of replacing the fresh water lines between my forward and aft tanks and found that there is no check valves between the two tanks. I ask this question since it appears that when I fill up either of the tanks the water will flow to the other tank and appear to fill both tanks at the same time. I would like to keep the filling process separate and was going to install check valves on the output side of each tank so this does not happen.

Just looking to see if anyone has done this and found it to be problematic for any reason. I cant find any reason why it would.

Thanks for the help.
__________________
Advertisement

__________________
Heart Warrior-Island Gypsy 40
Daniel & Barbara Silverman
HeartWarrior is offline   Reply With Quote
Old 10-26-2020, 07:26 AM   #2
Valued Technical Contributor
 
DavidM's Avatar
 
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 5,600
Unlike raw water cooling systems where check valves are sometimes considered, I don't think you need to worry too much about check valves sticking in potable water service.

I assume the fresh water pump will draw from both tanks through the check valves. FWIW that is very likely to cause one tank to be drawn significantly lower than the other one. Small differences in hose runs and turns on the suction side of a pump will make big differences in water flow between them. I would want a block valve in addition to the check valve to force water to be drawn from the fuller tank if this happens.

I guess if you rigorously manage filling and using water from your tanks it will work ok. Most people just want the tanks to equalize during use so they don't have to worry about them.

David
__________________

DavidM is offline   Reply With Quote
Old 10-26-2020, 07:53 AM   #3
Veteran Member
 
City: Grand Rapids, MI
Join Date: Sep 2020
Posts: 39
I'm new to trawlers, but on the sailboats we don't normally connect multiple water tanks together at all. You use valves to select which tank to draw from, but never more than one at a time. On the last boat one tank was much smaller than the other. We would draw from the large one and when it ran dry we switched to the smaller one as a backup, and start looking for a refill opportunity.
jgwinks is offline   Reply With Quote
Old 10-26-2020, 07:56 AM   #4
Guru
 
City: Northport
Join Date: Aug 2015
Posts: 1,682
"Just looking to see if anyone has done this and found it to be problematic for any reason. I cant find any reason why it would."

We always found that shut off valves between our two water tanks to be very helpfull in a number of ways...
- we always could reserve one tank and knew exactly how much was left
- filling each tank fully was possible with the valves
- drawing from each tank fully was possible with the valves
- if one tank were to leak, or a water line left open, or a tank got contaminents in it the other was preserved.
YMMV
smitty477 is offline   Reply With Quote
Old 10-26-2020, 08:11 AM   #5
Guru
 
OldDan1943's Avatar
 
City: Aventura FL
Vessel Name: Kinja
Vessel Model: American Tug 34 #116
Join Date: Oct 2017
Posts: 6,349
Just put in an isolation valve between the 2 tanks.
My N46 had about 5 isolation valves for the 5 tanks.
I think they used the FW as ballast and buried them in the keel.
First cruise, I did not top off the water tanks and ran out of water. I did not discover the 5th isolation valve till the end of the cruise. After that, I topped off all the tanks isolated all but 2 tanks, fwd port and starboard tanks. Never had trouble again. The 5th tank was the smallest tank.
I did install a 150gpd water maker...... The intent was, if I started to get low, turn it on and over 5 or 6 days, fill the water tanks. Never used it.
__________________
The meek will inherit the earth but, the brave will inherit the seas.
OldDan1943 is offline   Reply With Quote
Old 10-26-2020, 08:12 AM   #6
Veteran Member
 
City: Grand Rapids, MI
Join Date: Sep 2020
Posts: 39
Considering the different environments of power vs. sail, I can see an advantage in having the tanks connected together on a powerboat if they are positioned port and starboard. Drawing one tank down before the other would affect the boat's trim. This would be a good argument for not having check valves, or having manual valves that are normally left open. On a sailboat this is exactly what you don't want to do, as the boat heels water would flow from the high tank to the low one and make the boat heel more. Some sailboats even have ballast tanks or use the potable water tanks to pump water to the high side and flatten the boat out. If the tanks are arranged fore and aft it wouldn't matter as much, and the advantages of keeping a reserve, isolating contamination, etc might take precedence.
__________________

jgwinks is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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



» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 12:34 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×