Cleaning fuel tank in situ

eddystone said:
I think the tank is stainless, not mild steel. What I don't know is whether it has baffles inside which make it more difficult to clean out and what is the state of the drain nut. Unless the boatyard has a clever solution I will probably do what you describe which is what I have done before and keep taking the Marine 16.
Click to expand...

If there are baffles you will see the weld marks.

Adding access is not a big deal... depending on your skill set.
 
lw395 said:
Poke the hose from a Pela-type oil extractor down the filler pipe and check you find clean diesel at the bottom of the tank.
If there is any crud, it will block the thin pela tube, I replaced mine with bit of 8mm bore plastic with a few inches of ali tube on the end as a weight. Suck out all the water and dirty diesel.
I let the diesel I took out settle and put the clean stuff back via a filter.

Get rid of any significant water and you are unlikely to have a problem.

I am not a fan of storing diesel over the winter, it goes off, but as you have a mild steel tank you may have to compromise.
If I was going to spend your cash for you, I'd consider changing the tank.
Click to expand...

Petrol goes off. Diesel lasts years. Full tanks best practice.
 
Poey50 said:
Eddystone and Hydrozoan, I copied the parts in this ASAP diagram. https://www.asap-supplies.com/media/faq/asap12-0246gb-1018-basic-fuel-polishing-system.pdf

Oh and I used 10mm ID hose as specified rather than 8mm as I mistakenly said above. Big enough to suck up crud that will block a Pela but small enough to get both filter inlet and return hoses through the deck filler.
Click to expand...

+1 Yep I used the basic info provided by ASAP and built my own system very similar to Poey50's.
I posted a thread on here several years ago giving all the details, do a search and you might find it.

I use a length of microbore central heating type copper tube, 10mm, (same as fuel pipe) to poke down into the bottom of the tank, and have a clear hose between the top of the tube and the filter so I can see the colour of the fuel being picked up and if there are any black bits in it.
It's been extremely effective and I usually have to re-polish every 2 years.

My tanks have a central baffle, so I drilled & tapped a 10mm hole in the centre of each side at the top and sealed them afterwards with a bolt and O-ring. (So 4 holes in total, 1 hole each side of the baffle per tank, x 2 tanks)
This enables me to poke the copper pipe into all areas at the bottom.

I can thoroughly recommend this approach and making a rig to do your own polishing. It costs about the same or less than the cost of one visit from an external company - but you have the kit for good, and the only ongoing cost being filter elements.
 
Elessar said:
Petrol goes off. Diesel lasts years. Full tanks best practice.
Click to expand...
The first three words are correct, the rest is utterly wrong according to people like Shell, BP.....

Maybe fuel companies need to do a bit less science and read a bit more folklore.
 
lw395 said:
The first three words are correct, the rest is utterly wrong according to people like Shell, BP.....

Maybe fuel companies need to do a bit less science and read a bit more folklore.
Click to expand...

I closed a building in London about 6 years ago which had quite a few standby generators with large fuel storage tanks in the basement.
I sold the red diesel to a fuel company which sold it on. It had been there for years, the tanks were installed in the 60s and were never ever drained, and there was over 250,000 litres down there.
We were charged for disposing of the sludge and got paid for the fuel they could sell, which was the vast majority of it.
It was quite a few tankers full.
And yes I did try (and failed) to figure out how to get it to Southampton!

Whatever, be a bit more specific about your source because I think you are wrong. Not folk-law, we received a 6 figure sum for the fuel, even after deducting the cost of bad fuel disposal, transport and making the tanks clean and safe (as the building was being demolished)

Whats more, most boaters fill their diesel tanks, has anyone had a problem with diesel going off? Bug yes, going off no.......
 
Last edited:
BP:
STORAGE LIFE
Under normal storage conditions diesel fuel can be expected to stay in a useable condition
for:
• 12 months or longer at an ambient of 20ºC.
• 6-12 months at an ambient temperature higher than 30ºC.
As diesel gets older a fine sediment and gum forms in the diesel brought about by the
reaction of diesel components with oxygen from the air. The fine sediment and gum will
block fuel filters, leading to fuel starvation and the engine stopping. Frequent filter changes
are then required to keep the engine going. The gums and sediments do not burn in the
engine very well and can lead to carbon and soot deposits on injectors and other combustion
surfaces.
The expected life of a diesel fuel is indicated by the oxidation stability test ASTM D2274.
The test measures how much gum and sediment will be deposited after keeping the fuel at
95°C in the presence of oxygen for 16 hours. It roughly corresponds to one year storage at
25°C. A result of less than 20mg/L of sediment and gum after the test is considered
acceptable for normal diesel.
 
If the tank in your 32 is the same or similar to the one in my 34 I would be very wary of problems with the drain plug. After more than 20 years untouched the drain plug began to drip a little rust. I went to tighten it up a little, only to realise that the threads had almost failed. Fortunately there was very little fuel in it, which I was able to decant. I removed the tank and unscrewed the drain plug, which almost fell out. Over the years the water lying in the bottom of the tank had set up a galvanic cell between the brass plug and the stainless boss into which it screwed. The thread is very fine, so corroded quite readily.

I retapped the boss with a BSP thread and fitted a new plug with a far coarser thread. On reflection it would have been better to fit an additional tap instead to allow periodic draining of any water.
 
Trundlebug said:
......It's been extremely effective and I usually have to re-polish every 2 years.

........I can thoroughly recommend this approach and making a rig to do your own polishing.
Click to expand...

As a bystander your comments make interesting reading. I’ve often thought about making such a rig, perhaps an ideal over-winter project.

I don’t use a lot of fuel over an average U.K. season, I tend to keep the tank full and (infrequently) use Millers bug treatment.

Why do you have to re-polish every two years? Do you consume a lot of fuel? Dodgy filling stations? Just bad luck?

What size filtration do you use?

TIA :)
 
lw395 said:
BP:
STORAGE LIFE
Under normal storage conditions diesel fuel can be expected to stay in a useable condition
for:
• 12 months or longer at an ambient of 20ºC.
• 6-12 months at an ambient temperature higher than 30ºC.
As diesel gets older a fine sediment and gum forms in the diesel brought about by the
reaction of diesel components with oxygen from the air. The fine sediment and gum will
block fuel filters, leading to fuel starvation and the engine stopping. Frequent filter changes
are then required to keep the engine going. The gums and sediments do not burn in the
engine very well and can lead to carbon and soot deposits on injectors and other combustion
surfaces.
The expected life of a diesel fuel is indicated by the oxidation stability test ASTM D2274.
The test measures how much gum and sediment will be deposited after keeping the fuel at
95°C in the presence of oxygen for 16 hours. It roughly corresponds to one year storage at
25°C. A result of less than 20mg/L of sediment and gum after the test is considered
acceptable for normal diesel.
Click to expand...

Well I just told you I sold 100's of thousand of litres of oil that was 10s of years old. They tested and bought it. It was however kept cool as it was in a basement.
Even what you just posted absolutely does not support the practice of leaving the tank half empty if laying up. Condensation is the enemy, not extended storage.
 
Elessar said:
Well I just told you I sold 100's of thousand of litres of oil that was 10s of years old. They tested and bought it. It was however kept cool as it was in a basement.
Even what you just posted absolutely does not support the practice of leaving the tank half empty if laying up. Condensation is the enemy, not extended storage.
Click to expand...

Both condensation and extended storage are enemies IMHO.
Your anecdote about fuel from last century may not be entirely relevant to fuel from last year.
You also mention there was sludge. In a boat, the motion of the tank may mix any small amount of sludge into the fuel with undesirable consequences.
Laying up, I think the best thing is to keep only a small amount of fuel and check for water at the start of the new season before buying the new fuel that you need.
 
Sea-Fever said:
Ditto...ended up doing the same and fitted a DIY inspection hatch using nitrile gasket of about 2-3mm and some SS fastenings. Whilst cleaning out the tank I found a)no bug and b)lots of bits of old electrical tape floating around just waiting to block a fuel line....now amount t of filtering would have fixed that!
Click to expand...

Oh yes...my tank had a baffle and I was just able to fit a pressure washer into both sides of the baffle so be careful on your hatch placement if that is the route you go down.
 
To pick up on a couple of points that have been raised -

It is often said that tanks should be left full for the winter 'to reduce condensation', but I remember reading (or watching a video) of someone who had set up a test rig and demonstrated there was no reason for more condensation from a tank only part full compared to a full one. ISTR the issue was that, even though there is air in the emptier tank, there is such a tiny amount of moisture in a single tankful of air, and negligible subsequent exchange of it for fresh air.

Someone above seemed to imply that polishing might need doing more often if the engine got more use. Apart from that meaning more fills and the associated risk of debris with them, I would have thought the reverse would be true. Fuel is being polished all the time the engine is running as the surplus filtered fuel is returned from the engine to the tank, and rapid turnover of fuel will largely eliminate the likelihood of bug forming.
 
vyv_cox said:
If the tank in your 32 is the same or similar to the one in my 34 I would be very wary of problems with the drain plug. After more than 20 years untouched the drain plug began to drip a little rust. I went to tighten it up a little, only to realise that the threads had almost failed. Fortunately there was very little fuel in it, which I was able to decant. I removed the tank and unscrewed the drain plug, which almost fell out. ...
Click to expand...

How was your tank fitted and how difficult was it to remove, may I ask? I appreciate that it may not be exactly the same arrangement as on S32s, but it might give us a pointer.

EDIT: Apologies, Vyv - a bit more searching reveals we have been around this loop before, at http://www.ybw.com/forums/showthread.php?466527-calling-Sadler-32-owners-fuel-tank-question. There you said the S34 fuel tank is at the aft end of the cockpit locker, which is the opposite end from its position on the S32, though the method of fixing may perhaps be similar and an indication of the 'degree of difficulty' of removal still perhaps helpful.
 
Last edited:
lw395 said:
Both condensation and extended storage are enemies IMHO.
Your anecdote about fuel from last century may not be entirely relevant to fuel from last year.
You also mention there was sludge. In a boat, the motion of the tank may mix any small amount of sludge into the fuel with undesirable consequences.
Laying up, I think the best thing is to keep only a small amount of fuel and check for water at the start of the new season before buying the new fuel that you need.
Click to expand...

Well we have to agree to differ. If there’s hardly any fuel in your tank, water will end up in your tank. And you won’t be able to use your boat in winter. Both things are intolerable for me.
Sludge in suspension in fuel is ideal. It ends up in the filter as intended. Building up in the bottom of the tank is bad as it eventually blocks pipes before the filter. I found this out the hard way.
 
Last edited:
Hydrozoan said:
How was your tank fitted and how difficult was it to remove, may I ask? I appreciate that it may not be exactly the same arrangement as on S32s, but it might give us a pointer.

EDIT: Apologies, Vyv - a bit more searching reveals we have been around this loop before, at http://www.ybw.com/forums/showthread.php?466527-calling-Sadler-32-owners-fuel-tank-question. There you said the S34 fuel tank is at the aft end of the cockpit locker, which is the opposite end from its position on the S32, though the method of fixing may perhaps be similar and an indication of the 'degree of difficulty' of removal still perhaps helpful.
Click to expand...

So we have! On the 34 the tank is bolted to the cockpit sides using tangs fore and aft. The aft ones are a little difficult to remove, a socket with a ratchet and an extension seemed like the best tool for the job. The tank is a tight fit through the locker lid aperture, from memory I needed to rotate the tank 90 degrees to get it out, and some see-sawing was needed to get the tangs through.
 
vyv_cox said:
So we have! On the 34 the tank is bolted to the cockpit sides using tangs fore and aft. The aft ones are a little difficult to remove, a socket with a ratchet and an extension seemed like the best tool for the job. The tank is a tight fit through the locker lid aperture, from memory I needed to rotate the tank 90 degrees to get it out, and some see-sawing was needed to get the tangs through.
Click to expand...

I think I saw your warning about the drain plug on an earlier thread, Vyv hence my caution but it's impossible to do anything with it without removing the tank because of its position. It's not weeping as far as I can see.
 
One thing I haven't done for a bit but will is to replace the O ring on the filler - this must be the cheapest and simplest precaution to keep water out of your fuel!
 
vyv_cox said:
So we have! On the 34 the tank is bolted to the cockpit sides using tangs fore and aft. The aft ones are a little difficult to remove, a socket with a ratchet and an extension seemed like the best tool for the job. The tank is a tight fit through the locker lid aperture, from memory I needed to rotate the tank 90 degrees to get it out, and some see-sawing was needed to get the tangs through.
Click to expand...

Thanks. I think (though it is not absolutely clear) that Amlov may have outlined the S32 tank removal process at the end of that previous thread (http://www.ybw.com/forums/showthread.php?466527-calling-Sadler-32-owners-fuel-tank-question/page3) - and perhaps Champagne Murphy, who originated it, may actually have performed the task? It would be nice to have more details of what to expect if anyone has them.
 
You must log in or register to reply here.

Share this page

Top