Need To Clean Fuel Tank

[gmcairns]

I have a 23 year old sailboat and the diesel fuel tank needs to be cleaned. The tank can not be removed so does anyone have any experiance with this? I have about an inch and a half access hole on the top of the tank.

[phantomracer]

make a bigger hole? The previous owner of our boat made a big access panel to behind the tank baffle for cleaning access. I open and clean it every 3-4 years.

With pre-filtering every ounce of fuel, it has stayed quite clean.

But, unsure if you can, but make a larger hole, one in each baffle to ensure you clean all surfaces

[Vasco]

Get a fuel polisher. They will pump out your fuel, clean it by running it through a few filters, clean the tank by scrubbing it with the clean fuel and then return the fuel to to the tank. It can be done through a small access hole. Mine was done through the hole the sender sits in.

[capngeo]

I acquired a boat with EXTREME algae in the tank once.... to the point you could scoop up handfuls! I pumped off the fuel through a double set of filters designed for retail diesel pumps into a bladder tank on deck. Then used a pressure washer and degreaser to clean up the visible gunk on the walls and baffle. Then I mixed a fairly high concentration of degreaser and water and filled the tank to the top. A week later the inside of the tank was clean as new.

The biggest issue was dealing with the oily water; there were six 55 gallon drums of it! That was done by boiling off the bulk of the water, then disposing of the sludge with the waste oil and filters by the recyclers.

Of course this was all done in a yard where I used to work..... NOT in my back yard!

[phantomracer]

I run the tank near empty toward the end of the year ( < 5 gallon). I just pump my tank empty once hauled out and donate the fuel to the boat yard. manually clean all surfaces with your favorite cleaner. replace with new fuel.

The question is how much fuel is in the OP's tank and if he wants to save it or toss it.

Cost is nothing to do, other than any fuel that is disposed of.

Making opening panels to the tank is not a bad idea whichever way the OP goes. Whether for inspection or cleaning the tanks.

[KDH]

We originally had no access to the tank except through the sensor hole. We hired a company to come and pump out the tank, clean the fuel through a centrifuge type filter. They could not clean the tank itself. They wanted a small fortune to put an access port in the tank. Lasted about a year but we had a fuel filter failure just as we were about to enter a harbour in Guadeloupe and lost the engine. We still had the sails up and headed back out to deeper water. Couldn't get the engine going again. Fortunately our friends were able to tow us in. So, in Guadeloupe we had the tank emptied again, filtered by hand (not a fancy centrifuge) and an access port put in for about half the cost of just having it filtered in Maryland. That cleaning has lasted us about 9 months but I noticed we are getting a lot of sediment in the filter this week despite our efforts to keep the diesel we put in clean so I guess we'll have to do it again. Depending on what your tank is made of and how much clearance you have you might be able to do it yourself. In Maryland the contractor told us they'd have to take the whole tank out, to put the port in. In Guadeloupe the guys said no problem (7-8" access between the top of the steel tank and top of the compartment) and they took measurements the same day they cleaned out the tank and had the port done the next day without removing the tank.

[DeepFrz]

phantomracer, that is an impressively clean bilge you have. Nice way to support the floors.

[casual]

I,just finished doing what you described.I,bought a 70.00 pump from NAPA I,beleive 70gph plumbed it to a racor filter stuch a 3/8 " line with a piece of welding rod taped to it to wiggle it around the tank taped scotch bright pads to the end of the pick up line I,inserted the pick up line thru the fuel fill and the return to the tank return line.Pumped and returned for about 2 hours.Started out with a 30 micron filter down to a 2 micron filter when it didn't plug I,quit.I,was working with a 35 gal tank with about 25 gal of fuel in it.I,am satisfied with the results probably cost me 200.00 in all with filters.Better than the 500.00 I,was quoted for just fuel cleaning.Good Luck

[Vasco]

Originally Posted by casual

it.I,am satisfied with the results probably cost me 200.00 in all with filters.Better than the 500.00 I,was quoted for just fuel cleaning.Good Luck

$500 is kind of pricey. Got mine done in Ft. Lauderdale for under $300. Guy came out in his 30 foot aluminum tanker type boat. Pumped the fuel into his boat, stuck a wand in the sender hole, cleaned it all out (pretty good pressure) inspected with a mirror, and pumped the clean fuel back into the tank.

[phantomracer]

Originally Posted by DeepFrz

phantomracer, that is an impressively clean bilge you have. Nice way to support the floors.

thanks. Not bad for a 44 year old boat If you like the bilge, you will like the rest of the boat Home / Ohlson 38 | Mildred Rose / Phantomracer gallery

[bobconnie]

All I can say about Phantomracers boat is !! To me thats Bristol Fashion !! pure and simple! I covet few things in life ! But ya can't not love his detailing!! Just a sweet boat !! FIRST Class work !!

[Nicholson58]

Our boat was 24 years without cleaning I think. We have 5 tanks; 380 gallons total. There are an additional 4 tanks of identical construction for water. Tanks are 1/8 inch wall 316 SS all welded. Each tank has a 12 X 18 inch or so inspection port. When we started the 3-year on the hard refit I emptied 250 gallons and gifted the yard owner. (good politics). The main tank had 4 inches of sludge resembling dead garden slugs. We dumped the bad stuff in the oil recycler tanks at the diesel repair shop. The insides were then mopped and scrubbed with rags. I used a pump garden sprayer to apply FAST ORANGE (without grit) over the interiors. I buttoned up the tanks and let them cook for a couple of days. I used a pressure washer to blast off the remaining residue. I also removed all 1 inch steel pipe and bronze valves and replaced woth SS pipe and new bronze valves with interconnectiong 1 inch USCG hose. Interestinly, the upper lines (fill) - also 1 inch, are all copper.

We also have dual Racor filters and a switching valve. I have not even seen water, let alone dirt, in the bowls.

I can't imagine permanent tanks without clean-out ports.

[DeepFrz]

All I can say about Phantomracers boat is !! To me thats Bristol Fashion !! pure and simple!

Very nicely done. Beautiful boat.

[Dustymc]

I built a pump and filter in a box thing for my boat after failing to find anyone on SF Bay who'd bother returning a message. It uses $10 filters from Tractor Supply and plugs into 12v, and you're welcome to borrow it. It's on my boat in Richmond - send me a PM.

[gmcairns]

Thanks for the help everyone. Yesterday we pumped the 7 gallons of diesel out with a hand pump and filtered it at the same time. Then we returned about a gallon of the cleaned fuel to the tank spraying it around the inside. We then then pumped this dirty fuel out while filtering it again. We repeated this 7 or 8 times. After that we vacuumed the remaining small amount with a shop vac connected to a 1/2 inch hose. I fell pretty good about it think I got 95% of it out. It sure looked cleaner anyway. I do think an access hole is the way to go just big enough to get my hand and arm in. A 4 inch hole saw would probable do the trick.
Thanks again. G.