Plumbing options for 2 identical fuel tanks - 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 02-25-2010
Zanshin's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Germany
Posts: 2,165
Thanks: 0
Thanked 14 Times in 14 Posts
Rep Power: 8
Zanshin is on a distinguished road
Plumbing options for 2 identical fuel tanks

My boat currently has 250l fuel in one tank and 750l water in 3 tanks. Since I have a watermaker I will make do with just 500l of freshwater in 2 tanks and will convert one of those water tanks to diesel.

The manufacturer of the water tank has stated that the material is not suitable for fuel storage. I am ordering an identical tank in the correct plastic from the same manufacturer (through Jeanneau). Once it arrives I will have 2 tanks in the aft cabin side by side, the port one has 2 fuel pickups, returns & shutoffs (for main and genset), the fuel line going to a Racor filter.

Now I am in the process of trying to decide plumbing options for the fuel. The only decision I've made so far is to put in a dual Racor filter and a preference for KISS, i.e. keeping the fuel delivery system from just one tank and trying to come up with an optimal (and simple) method of getting fuel levels either automatically balanced or some simple manual transfer method to the port ('live') tank.

My goal in doing this is to increase my range and not necessarily to create redundant systems, but I could be convinced to have 2 separate systems.

I'd like to hear opinions and suggestions from the forum and will certainly hear some viewpoints or aspects that I hadn't thought about - thanks in advance.
__________________

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

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
  #2  
Old 02-25-2010
jrd22's Avatar
Courtney the Dancer
 
Join Date: Nov 2000
Location: San Juan Islands., WA, USA
Posts: 3,815
Thanks: 3
Thanked 14 Times in 14 Posts
Rep Power: 14
jrd22 will become famous soon enough
I prefer separate systems, although they require more direct management than just a simple crossover pipe between the two tanks (ultimate KISS). With a crossover pipe between the two tanks and all the supply/return lines from one tank only, the fuel can transfer to the leeward (low) side when the boat is heeled. This can cause fuel starvation while motor sailing if the fuel level is below half and all the fuel transfers to the "storage" tank. You can control this with valves on both sides of the crossover line (which should be installed at each tank so you can shut them off in the case of a leak in the crossover), but that requires management and access to areas that are generally difficult. If you simply run a redundant set of supply/return lines from the second tank to your dual racor, with a set of valves and "T's" you can select either tank and simply monitor levels in each. That is exactly the system that we have and have found it easy to manage, with the inherent safety of redundant systems.
__________________
John
SV Laurie Anne

1988 Brewer 40 Pilothouse

Reply With Quote Share with Facebook
  #3  
Old 02-25-2010
Senior Member
 
Join Date: Oct 2009
Location: Gloucester, MA
Posts: 584
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 5
klem is on a distinguished road
I agree with jrd22 on two completely separate systems. On some powerboats, the tanks are tied together (requires an extra pump) so that fuel can be moved to change trim but it shouldn't be necessary on a sailboat unless one tank is all the way in the bow or stern.
Reply With Quote Share with Facebook
  #4  
Old 02-25-2010
Cruisingdad's Avatar
Best Looking MALE Mod
 
Join Date: Jul 2006
Location: Washington State
Posts: 9,904
Thanks: 3
Thanked 106 Times in 53 Posts
Rep Power: 10
Cruisingdad is a jewel in the rough Cruisingdad is a jewel in the rough Cruisingdad is a jewel in the rough
I suspect we will be doing the same thing soon. How I am going to do it:

Our second tank will be very close to the first tank, similar to yours.

I am going to put a Y in the fuel fill line. This Y can be selected for tank one or two. This is easy stuff.

I am going to put a T in the fuel vent to select between tanks. SO when you select Tank 2, you also change the vent to tank 2.

I am going to T the returns and supplies. This again is easy to do. With teh valves, I will be able to choose which tank to pull from and which to deliever to. If I were you, I would run the Filter Boss, if that is what yo uare going to use, between them so you can effectively filter between tanks as well as out. You could even put a manual pump inbetween them so that you could run the Filter Boss without having to run a engine. THis allows you to polish your diesel without running the engine. THis is popular amongst trawlers and larger motor sailors.

THe RIGHT way is to run new everything, including the deck fill and vent, but I am too lazy to do all that and do not get excited about another hole in my deck.

My opinions.

Brian
__________________
Sailnet Moderator



1987 Tayana Vancouver 42, Credendo Vides, (Mom and Pops boat, F/T Mobile Live Aboards in Puget Sound)

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


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


Follow me on Facebook:

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
  #5  
Old 02-25-2010
Cruisingdad's Avatar
Best Looking MALE Mod
 
Join Date: Jul 2006
Location: Washington State
Posts: 9,904
Thanks: 3
Thanked 106 Times in 53 Posts
Rep Power: 10
Cruisingdad is a jewel in the rough Cruisingdad is a jewel in the rough Cruisingdad is a jewel in the rough
BTW, it may be better just to put a permanenet Y (not changeable) so that both tanks can use the Fuel Vent.
__________________
Sailnet Moderator



1987 Tayana Vancouver 42, Credendo Vides, (Mom and Pops boat, F/T Mobile Live Aboards in Puget Sound)

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


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


Follow me on Facebook:

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
  #6  
Old 02-25-2010
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
You really don't want to have the fuel vent line on a switch...better to leave both tanks properly vented...
__________________
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
  #7  
Old 02-25-2010
Bene505's Avatar
Glad I found Sailnet
 
Join Date: Jul 2008
Posts: 3,567
Thanks: 5
Thanked 39 Times in 38 Posts
Rep Power: 8
Bene505 will become famous soon enough Bene505 will become famous soon enough
Quote:
Originally Posted by sailingdog View Post
You really don't want to have the fuel vent line on a switch...better to leave both tanks properly vented...
CD's just making sure we are awake.

If you fill your tank from a marina with a (cold) underground fuel tank on a hot day, the fuel will expand soon after. And with a full tank, there will be relatively little air above the fuel to absorb that fuel expansion (via an increase in air pressure). So the pressure in the tank will get pretty high until BANG you burst your very full fuel tank.

(BANG added for emphasis and color. Haven't really ever burst one of those, they may go BURP or CLANG for all I know.)

Regards,
Brad
__________________
.
.
Great minds discuss ideas;
Average minds discuss events;
Small minds discuss people.
.
The best minds discuss sailing.
.
Reply With Quote Share with Facebook
  #8  
Old 02-26-2010
Cruisingdad's Avatar
Best Looking MALE Mod
 
Join Date: Jul 2006
Location: Washington State
Posts: 9,904
Thanks: 3
Thanked 106 Times in 53 Posts
Rep Power: 10
Cruisingdad is a jewel in the rough Cruisingdad is a jewel in the rough Cruisingdad is a jewel in the rough
You are right about the permanent venting. On the venting, follow the second idea I had and permanent T vent. No switching.
__________________
Sailnet Moderator



1987 Tayana Vancouver 42, Credendo Vides, (Mom and Pops boat, F/T Mobile Live Aboards in Puget Sound)

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


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


Follow me on Facebook:

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
  #9  
Old 02-26-2010
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
More importantly, what happens when you are running from a full tank and you forget to open said vent... and the engine dies just at the worst possible moment... and then you have to bleed the fuel lines to get the thing to work again... and if you've got a really good fuel pump, what happens if you drop the volume of the tank enough and the atmosphere decides to help you out—applying 14 lbs per square inch... If the top of the tank is 20" x 15" that's an awful lot of pressure.
Quote:
Originally Posted by Bene505 View Post
CD's just making sure we are awake.

If you fill your tank from a marina with a (cold) underground fuel tank on a hot day, the fuel will expand soon after. And with a full tank, there will be relatively little air above the fuel to absorb that fuel expansion (via an increase in air pressure). So the pressure in the tank will get pretty high until BANG you burst your very full fuel tank.

(BANG added for emphasis and color. Haven't really ever burst one of those, they may go BURP or CLANG for all I know.)

Regards,
Brad
__________________
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
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
Diesel Fuel Essentials Tom Wood Gear and Maintenance Articles 0 03-22-2004 07:00 PM
Diesel Fuel Essentials Tom Wood Her Sailnet Articles 0 03-22-2004 07:00 PM
Boat Plumbing Inspection Tom Wood Gear and Maintenance Articles 0 02-17-2004 07:00 PM
Diesel Fuel Concerns SailNet Gear and Maintenance Articles 0 07-08-2002 08:00 PM
Cleaning Fuel Tanks Sue & Larry Gear and Maintenance Articles 0 03-21-2002 07:00 PM


All times are GMT -4. The time now is 05:19 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.