cleaning diesel tanks that have been unused for some time.

[DrivinSteve]

Originally Posted by Maka

The question remains: How does one break loose the gunk in the bottom of the tank?

Depending on tank access and configuration, I have successfully broken loose the crud on the tank bottom by putting a few appropriately sized steel ball bearings in the tank and let them roll around for a bit under way. Make sure that the size that you use will not get stuck in your pickup tube.
If you try this, you MUST keep a good eye on your filter/separator and be prepared to change/clean it often. Once the bottom is so ablated, remove the ball bearings with a magnet.

[DeepFrz]

Originally Posted by Lepke

The issue of dirty tanks/fuel comes up every month or so. It's not that complicated. If you have a primary filter like Racor that has a element and a design that separates out water and a secondary of almost any kind, you have a basic fuel polishing system. I have dealt with long sitting diesel/dirty tanks at least a hundred times maybe hundreds of times. Unless someone shoveled in dirt or sand in volume, your filter system will filter it out. Using a good fuel conditioner will break down the sludge with a few fillings along with the motion of the ocean. The sludge dissolves (with a good conditioner) into tiny particles your filter catches. The conditioner helps extract any water so your filter housing separates it out. Carry extra filters, but you probably won't need them.
For example, my current boat has 1942 steel tanks that had no inspection openings. The fuel had sat for 6 years. At the time I used Algae-x conditioner at about 3x the normal mix. With it I added new fuel so the old fuel was about 60% Some tanks were empty so I added new fuel and 3x conditioner. I did a sea trial, no problems, Changed the filters and came home (500 miles, North Pacific in winter), no problems. 2 years later, I put in inspection ports during a remodel. I went inside to inspect. The tanks were clean, no sludge, light surface rust. Some pits in the bottom that I welded. I now run a 2 micron (in the primary) I change it at about 500 hours by vacuum gauge reading. My mains alone pump 70+ gallons an hour thru the primaries. So in 500 hours about 35,000 gallons (plus what ever the generators and boiler used) have been thru the filter.
I use a conditioner every time I fuel at the normal mix rate. I have clean (2 micron) fuel and I make sure I buy clean fuel. Currently I use Archoil AR6200 and it is excellent. It also helps the burn so much I get about 10% better mileage. My diesel 4x4, 3/4T PU gets 25mpg at 65mph. and I use about 8.5 gallons an hour @ 10kts in an 83' 80 ton boat w/DDs. I usually buy it on Amazon or Ebay. I don't make any money on it.

The part of this post about not worrying about crap in your tank because your filter will clean it out and your engine will act as a fuel pump strong enough to polish your fuel is absolute crap. Just because you haven't been stuck in a seaway with a clogged fuel line, yet, doesn't mean it isn't going to happen to you or to someone else. If you go to sea with a dirty fuel tank or a tank that you don't know is clean then you deserve what you get.

I am speaking from personal experience here.

Ensure that your tanks are clean and keep them that way. Your engine is not a fuel polishing system.

[hspanhaak]

Hello,
I have a solution for cleaning diesel tanks that cannot be reached easily;
buy tampons , make a string (fishing line )with a weight at the end
Lower this string inside your tank and leave there for a week or so.
All dirt, water will be soaked in the tampons (NOT The diesel)
After a week or so remove the string- you 'll be surprised how much dirt is collected this way ..
good luck!

[powsmias]

Thank you all.. some great stuff here.. appreciated

[davil]

DeepFrz

I looked with much interest at your video cutting inspections holes,and have these questions.
1) you empty the tank before but will not be there fumes that could spark with the cutting tool?
2) you used a saw blade not a hole saw?
3) the black rubber was neoprene?
4) the sealant? cannot read the label.
thank you for a very educational video
David

[sailah]

Diesel wouldn't ignite even fumes. If it were gasoline I'd take much more rigorous precautions.

Not sure if he cut with saw, but a very large hole saw would be almost dangerous to use. I've cut tons of larger holes up to maybe 4" on my industrial powermatic drill press geared down and the torque is impressive. Smaller than 3" no problem. Bigger than that I'm using a jigsaw with lots of WD40 as cutting fluid for aluminum. You'd also need a massive drill like a hole hawg your regular Makita would burn up drill holes that big. A deburr tool is also very handy for removing razor ragged edge.

Rubber for sealing oils, diesel TD is Buna-N I believe he stated that in video. Readily available in any size thickness etc. if I were to make an inspection plate, I'd buy a gasket like this first, and make the cover to fit. McMaster has tons of these I just picked a random size. Already cut in perfect circle for you.

https://www.mcmaster.com/#8516t143/=1cnfe2g

Stuff he used is called Form-A-Gasket. I've used Black RTV sealant from Loctite forms a tough rubbery seal that has some give. Mine was designed to not remove.

https://www.permatex.com/products/ga...ealant-liquid/

[davil]

again
thank you very much
I know about diesel not igniting but not sure was brave enough to test it!!!
However will do it as need to access the tank.
Taking note of your information,my new/old boat is been surveyed this week and this is one of the first projects/must do before anything else.
take care