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Old 12-12-2011, 01:33 PM   #1
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Fuel Tank Equalization

Some weeks ago, I found that* I needed to replace some fuel lines so I chose to replace all of them at the same time.* During the process, I did a complete inspection of the fuel system aboard my 40 Labelle.*

I found, much to my amazement, that the generator fuel return did not go to the center day tank but fed to the port tank.* So when we ran the generator often, the vessel would develop a slight list.

So with some careful planning, I devised a crossover series of valves and lines to connect both the starboard and port saddle tanks together; now the fuel is always equalized.
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Old 12-12-2011, 03:49 PM   #2
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RE: Fuel Tank Equalization

What about the generator return? I was doing the same and picked up a two 3 way valves to switch both supply and returns. This way I can return the fuel to the tank it is being drawn from.
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Old 12-12-2011, 06:30 PM   #3
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RE: Fuel Tank Equalization

It seems like the SOP for a lot of our trawler generator installs. When I overhauled my fuel system last year, I found the exact same thing and corrected it too. However, the way I understand it, the genset really only produces a few ounces per hour of return and doesn't make much of a difference in the ballast weight over the course of a tank.
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Old 12-12-2011, 07:16 PM   #4
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Fuel Tank Equalization

are all of your lines pumped or is there* gravity feed?

what I am wondering is that if you developed a list*would the side with the most weight on it* draw less fuel. Making the tank with less fuel supply more eventually emptying that side tank.

Say you are running a beam sea on one side you are constantly heeled over would the tank on the high side empty faster.

and if you do get one tank *with less fuel in it will it by gravity equal out?

It looks great I was just wondering.

SD


-- Edited by skipperdude on Monday 12th of December 2011 08:19:03 PM
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Old 12-13-2011, 11:29 AM   #5
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Fuel Tank Equalization

It appears you are using the center tank as the main tank to draw fuel from.* However, there no filters to clean/filter the fuel transferring from the side tanks, and no filter for the new equalizing line.* One of the main advantages of having a main/day tank is keeping the fuel clean.*
*
We have three 400 gallon tanks and all the fuel transferred between the three tanks is filtered so if a tank becomes contaminated/dirty it will not contaminate the other two tanks. If you are going to re plumb/design the fuel system you might want to think about filtering the fuel before it is transferred to the center tank.**
*
Usually fuel lines thsat draw from the bottom of the tank have valves which are closed except*when equalize the tanks.* Same with*sight glasses the vlaves should be close excpet to read the fuel level.* **


-- Edited by Phil Fill on Tuesday 13th of December 2011 04:07:55 PM
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Old 12-13-2011, 02:04 PM   #6
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RE: Fuel Tank Equalization

So am I totaly off on the subject as per my previous post. Or am I just not getting my point across.

*I would hate to have my boat go belly up because of a limber line

But it does seem that it could happen. I think shut off valves should be in order.

Whadda ya think?

SD
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Old 12-13-2011, 02:29 PM   #7
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RE: Fuel Tank Equalization

My equilizing valves are open. They were open when I bought the boat. I only shut them when I was doing my fuel filtering from one side to the other. Then I opened them again.

*

*
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Old 12-13-2011, 02:48 PM   #8
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RE: Fuel Tank Equalization

I understand but*do you preceive**possibility (as outlined in my first post )where open fuel lines could cause a capsize?

SD
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Old 12-13-2011, 03:09 PM   #9
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RE: Fuel Tank Equalization

My main motor returns fuel to the starb tank when running from the port tank for 12-13 hrs it seems to make no differance to the balance of the boat
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Old 12-14-2011, 05:09 AM   #10
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RE: Fuel Tank Equalization

Quote:
skipperdude wrote:
I understand but*do you preceive**possibility (as outlined in my first post )where open fuel lines could cause a capsize?

SD
*No. Not at all. The equilization line is small.
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Old 12-14-2011, 05:55 AM   #11
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RE: Fuel Tank Equalization

I would hope none of our boats would capsize because of full tanks on one side of the boat and empty on the other...if they might cause a capsize...REALLY bad design.

Some of us with older tanks would be scared to fuel up then....there's always a possibility of a rupture that could empty one side pretty quick.
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Old 12-14-2011, 08:58 AM   #12
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RE: Fuel Tank Equalization

I talked to a few boat builders in my area and was told that this is a something that can and has happened.

The suggestion was to install a couple of oneway valves in the fuel lines.

SD
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Old 12-14-2011, 06:50 PM   #13
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RE: Fuel Tank Equalization

Shame on the builders then...NO boat I have ever been on or owned would do it...and I've run hundreds while working at various marinas and deliveries...even knowing one would do it is pretty scary...
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Old 12-15-2011, 04:57 AM   #14
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RE: Fuel Tank Equalization

I think there is probably a lot more to that story than fuel gravity feeding from one tank to another.

Commercial fishing vessel operators are notorious for overloading, and modifying their boats with little regard for stability. Larger boats often use fuel for ballast and if that is done for the wrong reasons - sometimes moving weight to the "high side" to level the boat is the worst thing you can do.

Transferring fuel with a small pump is boring and people have other things to do and forget about it until it spills or something nasty happens.

Unless you routinely run around with a 30 degree list from some other loading condition, the likelihood of fuel gravity feeding from one tank to the other and capsizing the boat is probably less than getting hit by a meteorite.
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Old 12-15-2011, 06:29 AM   #15
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RE: Fuel Tank Equalization

Quote:
RickB wrote:
I think there is probably a lot more to that story than fuel gravity feeding from one tank to another.

Commercial fishing vessel operators are notorious for overloading, and modifying their boats with little regard for stability. Larger boats often use fuel for ballast and if that is done for the wrong reasons - sometimes moving weight to the "high side" to level the boat is the worst thing you can do.

Transferring fuel with a small pump is boring and people have other things to do and forget about it until it spills or something nasty happens.

Unless you routinely run around with a 30 degree list from some other loading condition, the likelihood of fuel gravity feeding from one tank to the other and capsizing the boat is probably less than getting hit by a meteorite.
*Read the Coast Guard report on the sinking of the tug VALOUR in 2006.
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Old 12-15-2011, 06:40 AM   #16
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RE: Fuel Tank Equalization

I agree about commercial boats...routinely modified by amatuer NA's (Ha!)

But the average* rec boat with the exception of some trawlers I doubt has the tankage to make that big of a difference (list yes/capsize I doubt) and the tanks are almost always so low in the boat I just don't see it.

Possible...sure...but again...just haven't seen a rec boat yet that*I think would be in that situation.*

Like the "rule of thumb" used for guessing whether you have too much ice on the topsides...if your roll time is getting getting longer and "hangs"...then yes I would worry about stability.* I have been known to say that liveaboard cruisers better watch out just like commercial fishermen forget about mods/gear...by the time you add on deck all the cruising stuff (bikes, dingy, kayaks, propane, barbecue, extra ground tackle, stairs, etc..etc)...you may HAVE affected your stability to a degree.
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Old 12-15-2011, 07:08 AM   #17
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RE: Fuel Tank Equalization

Quote:
dwhatty wrote:*Read the Coast Guard report on the sinking of the tug VALOUR in 2006.
Yep, that is exactly what I was talking about. There is usually far more to the incident than first meets the eye.

And, FWIW, in my personal opinion which is shared by a large number of professional mariners, those ATBs exist only to avoid the rules and standards that apply to ships in order to prevent the sort of accident that happened to the Valour.

*
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Old 12-15-2011, 09:15 AM   #18
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RE: Fuel Tank Equalization

Quote:
dwhatty wrote:*Read the Coast Guard report on the sinking of the tug VALOUR in 2006.
*Wow it took a village to sink a boat.

This might be an interesting required read for one employees to read no matter what business one is in.* It points out how with in a few hours several every day "let's try this instead" actions can cause such a large catastrophic event.
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Old 12-15-2011, 07:03 PM   #19
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RE: Fuel Tank Equalization

We lost two crab boats with all hands, the*Americus and Altair, sister ships out of Anacortes back in 1983.* Same situation offloaded fuel and stacked the decks high with 800 lb pots.* They rolled over and sank after leaving port in Dutch Harbor on the same day in calm seas.* Extensive testing by several labs determined the design*stability had been grossly exceeded causing the loss of both boats.* The book written afterwards is "Lost at sea."

On February 3, 1983, the men aboard Americus and Altair, two state-of-the-art crabbing vessels, docked in their home port of Anacortes, Washington, prepared to begin a grueling three-month season fishing in the notorious Bering Sea. Eleven days later, on Valentine's Day, the overturned hull of the Americus was found drifting in calm seas, with no record of even a single distress call or trace of its seven-man crew. The Altair vanished altogether. Despite the desperate search that followed, no evidence of the vessel or its crew would ever be found. Fourteen men were lost. And the tragedy would mark the worst disaster in the history of U.S. commercial fishing.
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Old 12-15-2011, 07:15 PM   #20
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RE: Fuel Tank Equalization

Sure...lots of commercial boats are lost for all kinds of reasons...but I find it hard to compare commercial vessels with their huge tankage spread around the vessel to be anywhere's near the same as most of our trawlers/vessels....unless of course you own a commercial conversion.
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