Fuel Tanks

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El Capitan
Dec 2, 2010
Vessel Name
Vessel Make
Chung Hwa 46 LRC
Inquiry --- how low do you let your fuel tanks get before you switch over (if you have more than one) or refuel?* Do you ever let them run completely dry (empty)?*Any concerns about mixing old fuel with new?* Do you do fuel polishing?*

* Tanks a lot,** KJ
Only time I let my tanks get pretty low is when I am going to clean them via the man holes.
Otherwise I fill them up after any major trip.
I do have a fuel polishing ( cleaning) system but mainly use it to transfer fuel from one tank to the other, polishing it on the way via the RACOR.
Out here where I am I have no problem loading on top. Most of our fuel suppliers are very reliable.
Some of our out ports once you get to the real back country may be a little questionable and then it pays to transfer as much of your existing fuel to other tanks/tank and then load new fuel separately until its quality is established or you have run it thru your polisher/filter
When the fuel level gets low, I either switch tanks or transfer fuel from another tank.* The Coot's fuel polishing system is handy for transferring fuel among tanks as well as priming the engine's fuel system.


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We only ever refuel from our club, they have a fairly new Deisel storage tank set up, never had any issues. Our tanks are never more than 1/3 full, no fuel polishers, I just throw in some fuel additves from time to time.

We have way too much fuel capacity for our needs.To fill my tanks would cost about $3,000. For us that is about 1 1//2 years of boating.

But... I do worry about the rust on top of the tanks, absolute nightmare to get at.
Andy G wrote:
* Our tanks are never more than 1/3 full, no fuel polishers, I just throw in some fuel additives from time to time.

But... I do worry about the rust on top of the tanks, absolute nightmare to get at.
*Do you have a fuel gauge on your console or a sight gauge?

I wonder how many folks still have the original fuel tanks.**** KJ


-- Edited by KJ on Sunday 27th of November 2011 01:55:02 AM
We have a sight guage and they are def origional.
Willy has a aluminum pipe plug in a hole on top of the tank. There's a small piece of floor that comes up to expose the plug. I unscrew the plug and insert a hardwood dip stick into the hole *..pull it*out slowly and observe the fuel level. When I bought the boat I was disappointed it did'nt have gauges but the dip stick works fine and if I was to build the boat new I'd change a lot of things *..but not the dipstick. The boat burns 1 gph and has 100 gallon capacity so I do'nt check the fuel often. My fuel source is 50 miles away (Ketchikan) and I usually top of when we go there. Hardly ever have any water at all in the tanks and am not very worried about water condensation but I do have a water extractor that removes even a drop of water.*
KJ wrote:*
I wonder how many folks still have the original fuel tanks.**** KJ


*Mine are still original from 1983.

I try to take on fuel when I am at about 3/8 left. I don't polish. I use multi stage filtration. 2 cycle oil as an additive. I have original sight tubes but I don't use them as my fuel gage is very accurate.
original, 1980.
no fuel guage
no sight tube
I refuel above 1/2 as a rule, occasionally have gone as low as 1/3. try to refuel in the fall, so as to minimize condensation over the winter.
no polish
no additives
Racors and on engine filters.
In the last 10 yrs the quality of fuel available in BC has become flawless, so no water/crud in the racor bowl any more.
For the winter the 1979 tanks arte ½ full so if a tank leaks there is enough room in the other tanks.* Using the Webasto have ran them down to 10% during the winter before refueling.* I use additives that absorb water and polish the fuel.** The Webasto is in the engine room which keeps the engine room dry and warm.*I try to turn the fuel once per year.
I did an experiment several years ago w "heet". A product made to make water mix w fuel. It's alcohol as I recall and I guess the idea is that water will mix w the alcohol and then the alcohol w the fuel. I put a small teaspoon of water in a bowl mostly filled w fuel. The water was clearly visible in the bottom of the bowl. I then put a teaspoon of "heet" in the bowl and stirred it around. When it settled there was the water in the bottom of the bowl just like it had been before I added the "heet". Did'nt seem to work at all. Have'nt used it since.
IN another 75 years when the hull finally gets wiggily , the MONEL fuel tanks will be cut out and used for another 100 years.

Uncle Sam has great standards!

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