Fuel tank modification needed?

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Fuel tank modification needed?

Postby Silverhow » Wed April 25th, 2012, 1:10 pm

Hi All

I am restoring a Vulcan 31 - similar to Golden Hind but steel. I have emptied the fuel tank (50 gal of out of date red diesel!) and it is like new inside, proof of a really great boat. My question is should I shorten the fuel pick up as advised by some friends. The fuel pick up is practically at the bottom of the tank, i have been told it should be about an inch off the bottom.
When Iemptied the tank there was no waterjust a small amount of brown sludge - not bad for a 48 year old boat, left standing for 10 years! As it has worked so far I am tempted to leave it as it is, any advice much appreciated. I plan to use ordinary diesel in future and am inrested in any way I can temporarily reduce the capacity fuel from 64 gal to half of this or less - for the next 4 years as wont use much fuel as am on inland waterways.

Thanks for your thoughts

Regards Tim

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Re: Fuel tank modification needed?

Postby JamesH » Fri April 27th, 2012, 6:35 pm

Hi I why not just fill up half full? If on inland waterways no need to worry about free serface effect. Do raise the pick up since it will pick up any rubbish,
Have fun
Love to have one on inland waterways idealy a ww wife twisted me into caravan doh!
Hi looking to build an WW!
any thoughts.
Have many of the materials for keel and frame.
Yours James

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Re: Fuel tank modification needed?

Postby Eventide Owners Group » Sat June 16th, 2012, 1:48 pm

The problem you will get with a half full tank will be condensation.

When you run the motor the bleed back is hot, heating the tank, any air above the fuel in the tank will have water in it and now being warm will condense its water content against the sides of the tank, as they are cooler.

That water will drain to the bottom of the tank,

If you have ever seen diesel bug you will always keep the tank full in future.! Full tanks rarely get the bug and the addition of a proprietory diesel bug killer is a good extra precaution.

The pick up just needs to be out of the sludge and water layer, with a clean well maintained tank that can be within half an inch of the bottom or less. (Assuming you have a sump or drain fitted where any sludge or water could be periodically drawn off.)

A water trap on the first filter will deal with anything inadvertently sucked up, just check the drain on that every now and again to ensure clean fuel only getting through. If you find water, suck it out of the tank with a long probe if you have no sludge drain.

I would leave the tank in situ after a careful clean out and just keep it full. (Fit an antisyphon to the filler, or a lock though!).

Wonder if there is a way of inserting an inflatable bladder to partially fill the tank with sealed air...??? Just a thought.. this could be removed when no longer needing to restrict the fuel content.....

Hope this helps

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Re: Fuel tank modification needed?

Postby Silverhow » Mon July 2nd, 2012, 12:59 pm

Many thanks for comments

An inflatable bladder was what i had in mind - does anyone know if there is such a thing on the market?

Regards Tim

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