How low can you run your fuel tank - SailNet Community
 1Likes
Reply
 
LinkBack Thread Tools
post #1 of 17 Old 11-22-2011 Thread Starter
Senior Member
 
Join Date: Jul 2007
Posts: 122
Thanks: 5
Thanked 3 Times in 3 Posts
Rep Power: 9
 
How low can you run your fuel tank

A quite a few years ago, in a different boat, I ran into problems with the fuel sloshing in the tank in rough water and the engine sucking air. The tank at this time was still half full. I was able to sail the boat in with no problem, but it has left me with a lasting fear of running the tank too low.

I am planning some exploring in the Inside Passage next summer where the winds will be fickle and the fuel stops scarce. Has anyone experience this sort of a problem? How low have you run your tank? I have a 35 gal capacity, but I'm wondering how much of that I can count on when calculating my maximum run time. I have never run this boat below half a tank.

John
johnharch is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 17 Old 11-23-2011
Coastal Carolinas
 
Norstar's Avatar
 
Join Date: Aug 2008
Location: Little River, SC
Posts: 97
Thanks: 3
Thanked 5 Times in 3 Posts
Rep Power: 8
 
John, We typically never let our PSC 34 run less than 1/2 tank but have on occasion let it go to 1/4. Never experienced any problems with pick-up tube sucking air and we always run our engine while entering our inlet (Little River, SC) from offshore which can sometimes be quite spirited. Remember the tanks V shape has the fuel more concentrated in a smaller space near the bottom as opposed to a uniform shape all the way down in the bilge. Maybe this helps?
John S
PSC 34 #201
Norstar
Norstar is offline  
Quote Quick Reply Share with Facebook
post #3 of 17 Old 11-23-2011
Member
 
Join Date: Aug 2010
Posts: 98
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 6
 
I successfully ran the tank on my 31 all the way to empty (not intentionally, of course). The water way pretty flat, though.

Al Lorman
PSC 31 No. 55, Ann West
Annapolis
AlLorman is offline  
Quote Quick Reply Share with Facebook
post #4 of 17 Old 11-23-2011
Senior Member
 
svjobeth's Avatar
 
Join Date: Nov 2008
Location: Savannah, GA
Posts: 192
Thanks: 7
Thanked 8 Times in 8 Posts
Rep Power: 7
 
We've run down to 1/4 tank in Jo Beth with no issues. Sucking air would seem to be a relatively unusual event, even in very severe conditions, given the shape of the tanks and pick-up tube positioning I've seen in most PSC's. A more likely problem would be the stirring up of the sludge and gunk that lay in the nether regions of every fuel tank and that mess getting drawn into the fuel system. Of course, when a tank draws really, really low, water ingestion can also become a potential issue.

Because we go through a tank of fuel so slowly aboard Jo Beth, I've made it a customary practice to have the tank opened, cleaned and the fuel inside polished every three or four years. I also service the fuel system twice per year. Minor overkill perhaps, but so far, so good; no sludge or water issues.

Bill & Lisa Ballard
S/V Jo Beth
1984 Pacific Seacraft Crealock 34, Hull #16

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


"Twenty years from now you will be more disappointed by the things you didn't do, than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover."
- Mark Twain
svjobeth is offline  
Quote Quick Reply Share with Facebook
post #5 of 17 Old 11-23-2011
Member
 
ralopata's Avatar
 
Join Date: Dec 2001
Location: Home Port: Rock Hall, MD
Posts: 57
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 14
 
John:

Not sure about the tank on the 34 but on the 40 the tank is baffled, which helps reduce the possibility of sucking air in a lively sea.

I agree with the previous posts about the dangers inherent in getting water and/or gunk from a low tank.

However, it's not a bad idea to find out how much USABLE fuel your tank holds. While that stated capacity may be 35 gallons, no fuel pickup can actually get every last drop. Some fuel is always going to be in the very bottom of a tank. Some sailors run their tanks "dry" intentionally and then fill them up to develop a "usable" fuel number.

On JUNO, for instance, although the stated capacity of the tank is 67 gallons, we have discovered (the hard way) that the pickup sucks air at 58 gallons.

Best wishes and Happy Thanksgiving to all,

Roger Lopata
JUNO
PSC 40 -- #46
ralopata is offline  
Quote Quick Reply Share with Facebook
post #6 of 17 Old 11-25-2011
Senior Member
 
svjobeth's Avatar
 
Join Date: Nov 2008
Location: Savannah, GA
Posts: 192
Thanks: 7
Thanked 8 Times in 8 Posts
Rep Power: 7
 
Quote:
Originally Posted by ralopata View Post
John:

Not sure about the tank on the 34 but on the 40 the tank is baffled, which helps reduce the possibility of sucking air in a lively sea.

I agree with the previous posts about the dangers inherent in getting water and/or gunk from a low tank.

However, it's not a bad idea to find out how much USABLE fuel your tank holds. While that stated capacity may be 35 gallons, no fuel pickup can actually get every last drop. Some fuel is always going to be in the very bottom of a tank. Some sailors run their tanks "dry" intentionally and then fill them up to develop a "usable" fuel number.

On JUNO, for instance, although the stated capacity of the tank is 67 gallons, we have discovered (the hard way) that the pickup sucks air at 58 gallons.

Best wishes and Happy Thanksgiving to all,

Roger Lopata
JUNO
PSC 40 -- #46
Excellent points Roger, on determining the useable fuel capacity of fuel tanks.

Jo Beth's fuel tank is baffled.

Bill & Lisa Ballard
S/V Jo Beth
1984 Pacific Seacraft Crealock 34, Hull #16

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


"Twenty years from now you will be more disappointed by the things you didn't do, than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover."
- Mark Twain
svjobeth is offline  
Quote Quick Reply Share with Facebook
post #7 of 17 Old 11-25-2011 Thread Starter
Senior Member
 
Join Date: Jul 2007
Posts: 122
Thanks: 5
Thanked 3 Times in 3 Posts
Rep Power: 9
 
Good points all. I'm not too worried about water and gunk as I'll have the tank cleaned this winter. I know it is baffled, but I don't know how well. I can see a fore and aft line on the top of the tank which would indicate a fore and aft baffle, but I don't know about side to side.

Those of you who have cleaned your tank, what kind of of access do you have? I have one square plate about 8 X 8. I can't imagine with the baffling that this will allow very good access. It is just bedded in and attached with what appear to be sheet metal screws. I'll have to have the fuel polished after removing and cleaning that.

Taking it out and running it until it ran dry would certainly give me the definitive answer, but may be a bit difficult. If I take it down to, say, 5 gallons remaining, that leaves me with still potentially needing to run for seven hours or more before it ran dry. So I would need to run for seven hours and be in a nonhazardous location when it went dry. Lots of tidal currents activity up here in the Northwest.

Looking back over my fuel log, I see that one time I actually did put 30 gallons in, but unfortunately I don't remember the circumstances, but I do know they were in flat water. I will keep better notes in the future!!!

I hate strapping fuel cans on deck, but I think I may have to resort to carrying a couple of 5 gal cans this year. Jeez, I'm already down to the water line. Run the engine at lower RPM and sail more. I'm still trying to figure out why I burn fuel faster than everyone else.
johnharch is offline  
Quote Quick Reply Share with Facebook
post #8 of 17 Old 11-26-2011
Senior Member
 
svjobeth's Avatar
 
Join Date: Nov 2008
Location: Savannah, GA
Posts: 192
Thanks: 7
Thanked 8 Times in 8 Posts
Rep Power: 7
 
John -

Cleaning the fuel tank and polishing the fuel contained within is a job I hire out. It's messy, smelly, and very toxic. For me, it's one of those jobs that's worth paying someone else to do.

Our access plate is a single circular plate, secured with sheet metal screws and gasketed. Of course, when the tank is opened, the old gasket has to be cleaned off and a new one made. I'm not too sure about access; I think that our tank has a single fore and aft baffle, and that access is reasonable, considering. I'll ask the mechanic that does ours and report back.

Bill & Lisa Ballard
S/V Jo Beth
1984 Pacific Seacraft Crealock 34, Hull #16

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


"Twenty years from now you will be more disappointed by the things you didn't do, than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover."
- Mark Twain
svjobeth is offline  
Quote Quick Reply Share with Facebook
post #9 of 17 Old 12-09-2011 Thread Starter
Senior Member
 
Join Date: Jul 2007
Posts: 122
Thanks: 5
Thanked 3 Times in 3 Posts
Rep Power: 9
 
Update

Update...

I bit the bullet and drained the tank and opened it up today. This was very informative.

I emptied the tank by running the electric fuel pump and pumping into 5 gal cans. It was able to suck it right down to the bottom, leaving only about a cup of fuel.

1. My access port is about 6" square secured with 8 machine screws tapped into the tank top and sealed with some sort of sealant. The sealant was hard and poorly adhering so that the plate just lifted right off. No doubt this would leak if the tank were over filled, accounting for the diesel I once found in the bilge.

2. When the access port was installed, some of the squeezed out into the tank. Most of it was stuck to the sides, but a few drips on the bottom of the tank hadn't stuck and were floating around waiting to plug the intake line.

3. The tank was remarkably clean. There was a little sludge in places on the bottom totaling maybe 5 sq in. in spots about the size a quarter. The fuel level sensor is quite clean. Cleaning it looks to be a relatively easy job if I put in another access plate on the port side.

4. There is one baffle running front to back from top to bottom with the bottom corner cut off on the pickup end. There is no way to get past this baffle to clean the port side or even inspect it, without installing another access plate.

5. Without any lateral baffling, it still seems to me that sucking air in rough conditions is a big concern, I'm thinking I don't have to worry too much until I get down to the last 5 gallons or so.
johnharch is offline  
Quote Quick Reply Share with Facebook
post #10 of 17 Old 12-10-2011
Senior Member
 
Join Date: Oct 2011
Location: Nanaimo B.C.
Posts: 2,593
Thanks: 3
Thanked 61 Times in 61 Posts
Rep Power: 4
 
Every system is unique. I'll tell you how mine works. Because I need a day tank for my diesel stove, I can fill it with a pulse pump or by return from injectors. It has a sight glass. The main tanks are vented thru this to outside.Because it's cold here the moisture from the air condenses in the day tank first and can be dealt with before it reaches either main tank by the drainable sump. Another line with it's own shut off and filter goes to the fuel manifold. If the unthinkable happens again I'll simply shut of the main fuel valve and open the day valve and be good for 4 more gallons TA DA!
Capt Len is offline  
Quote Quick Reply 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:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Fuel tank for First 42 first42 Beneteau 16 12-26-2014 11:01 AM
Need a new fuel tank AlLorman Pacific Seacraft 26 09-16-2011 12:08 PM
PSC 34 fuel tank mondofromredondo Pacific Seacraft 8 11-17-2009 05:22 PM
11.0 Fuel tank S2 Dave S2 1 08-14-2006 10:30 PM
Fuel tank doalmo Gear & Maintenance 0 10-13-2004 02:39 PM

Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome