Replace the diesel or not??

[shimari]

A few posters suggest that a partially filled tank can result in water build-up from the condensation. Here's a blog post by Maine Sail (I hope his health is improving each day) on the topic.

https://marinehowto.com/does-an-empt...nk-condensate/

He didn't find any water build-up from condensation in his test.

[dlj]

Originally Posted by shimari

A few posters suggest that a partially filled tank can result in water build-up from the condensation. Here's a blog post by Maine Sail (I hope his health is improving each day) on the topic.

https://marinehowto.com/does-an-empt...nk-condensate/

He didn't find any water build-up from condensation in his test.

I've been watching this topic (for a couple decades at this point) in other diesel forums outside of the marine world and the same conclusion was found.

Condensation problems from partially filled fuel tanks appears to be a myth....

dj

[Apollo366]

Here's my story on fuel tank bugs, a bacteria that grows in the fuel/water interface.

Bought the boat & PO reported that he had tank professionally cleaned the prior year. The boat had been used weekly for about 4-5 yrs in NJ even in the winter!
I was moving the boat down to FL to finish my upgrading and prep for going the the So Pacific. In NC we noticed big white clouds of steam coming out of the exhausts, not normal so went to Yanmar dealer in Oriental, NC for diagnosis and service.
Lead mech suspected bugs in fuel, but hard to reconcile with the symptoms.

He started a fuel polishing routine but lots of crud/bugs in filters. He pulled the first inspection/servicing 5" opening & was all clean tank, opened 2nd port & still clean as a whistle, but found there was no service port for section #3 of tank. We cut in a port for section #3 & found it was never cleaned & full of bugs/crud. He cleaned that section & removed all bugs, then polished fuel and returned to tank.

At his suggestion, he installed a modern Racor primary filter & replaced all fuel hoses to be sure no contamination, and installed a squeeze bulb in the input to Racor to make air bleeding easy compared to old method.

End result, never had a fuel problem after this extensive correction to fuel delivery system.

Yes it was pricey, but HAD to be done.

My recommendations; when ever you have fuel probs during or after a long passage have a cleaning port installed in the tank and inspect all sections, use endoscope for the other sections behind the baffles of the tank for contaminants and any other problems. If the bacteria adheres to the sides & bottom of the tank it will eventually clog filters at a high rate, and may clog them completely.

Hopes this helps your situation,

Wayne

[Annabel]

DLJ I didn't get back to your question, the boat, a Hanse 455 was new in 2019. We picked it up at Slovenia and sailed down to Greece. It holds 220 litres. If you are asking about usage, we usually keep it well filled, never go below quarter. We have had no trouble with it. It is just the length of time it has sat there getting older that was worrying us

[letsgetsailing3]

Not sure who you pay to dispose of fuel in Greece. Probably would cost the same to clean it.


Please do let us know what you end up doing.

[dlj]

Originally Posted by Annabel

DLJ I didn't get back to your question, the boat, a Hanse 455 was new in 2019. We picked it up at Slovenia and sailed down to Greece. It holds 220 litres. If you are asking about usage, we usually keep it well filled, never go below quarter. We have had no trouble with it. It is just the length of time it has sat there getting older that was worrying us

The boat is only 3 years old. So the O-ring seals on the fuel tanks are likely in good condition so moisture getting in through the fill connections is not likely. Unless one wasn't closed properly when you left. Coming back to the boat I'd carefully check the fill connectors - just to make sure they were properly closed when left. I would personally open them and see if they felt fully closed.

Not fully closed? - polish fuel.

Fully closed - Now the decision tree is affected by what you are going to do with the boat once you get back. Are you planning to head back to New Zealand? - polish the fuel, can't hurt. If you are going to burn off that tank in the Med essentially coastal cruising - I'd carry some extra fuel filters and not give in another thought...

We sailors can really get our panites in a wad about "what ifs".... You have to live with yourself. Only you know your personal risk level comfort. If it were my boat with what you are saying, I would simply carry extra filters (I do anyway) - start it up and go...

dj

[bil56]

I don't know the quality of your diesel in the United States;
but here in Europe (in France for me), there is a high percentage of so-called organic products, ethanol, esters extracted from cereals ... which makes the fuel more unstable over time, and in addition much less sulfur than before.
More, diesel stored for months/years in port tanks full of sludge and moisture.
Our main refiner Total only guarantees its diesel for 6 months. and the possible water associated with this diesel causes a lot of worries...

[NorthCoastJoe]

Set up a day tank and polish the fuel from the main tank on its way to the day tank. Run the engine off the day tank only.

[Annabel]

That's not an easy one. How many gallons are you talking about? How old is the boat? What is your normal diesel pattern with usage and filling?

The boat was launched in 2019 in Slovenia. Diesel pattern and usage is that we refill whenever we have an opportunity, and never let it get too low. We hold 220 litres. Thank you for your input

[mcarthur]

Also depends a bit on your engine - is it common rail or old-school (naturally aspirated or simple turbo)?
If common rail, then your filters need to appropriate, clean and working to really be sure that you're getting good fuel.
If old-school, you've got more leeway in poor fuel. Leeway doesn't equal putting crap in of course .

[Rumrace]

I used walnut shells dish soap and pressure washer. Brand new used.

[Annabel]

Originally Posted by bil56

Have you added an effective biocide to your diesel?
at start-up, it is possible to add a curative and non-preventive percentage ...

./.

No we didn't add a biocide. We will look at a possible curative. Thanks

[Annabel]

./.[/QUOTE]

Originally Posted by bil56

I don't know the quality of your diesel in the United States;
but here in Europe (in France for me), there is a high percentage of so-called organic products, ethanol, esters extracted from cereals ... which makes the fuel more unstable over time,...

We are actually from New Zealand, but the yacht is in Preveza, Greece.

[Dieseldude]

Originally Posted by Annabel

I hope this is in the right forum. We are returning to our yacht in Greece after the extended time of 2.5 years because of Covid (Grrrrr) we are a bit worried that our diesel may have developed a bug problem. My husband is rather convinced that we should empty the tank and replace it with new diesel. Any views on this anyone? Thank you

If the tank contains only a small amount, I would pump it out and properly disposed of it in marina waste oil tank. If a large amount, there should be a service who will do this. Whether worth hiring a fuel polishing or cleaning service just a cost of fuel vs. cost of service decision. But if you really have fuel algae or bacteria, the tank must be opened up and manually cleaned before filling with new or cleaned fuel. Pipe work must be flushed and filters replaced. Might be wise to send out fuel for lab testing, as minor growth will not be visible. How clear or cloudy does a sample look? You might consider sounding the tank with some water paste on the end of the sounding tape or stick. If it changes color, you have water. Water in fuel creates the environment for bio growth.


2 1/2 years is a long time to leave fuel in a tank, and it is quite possible for it to have developed bio growth. Cleaning is good maintenance anyway. If you do clean your tank, I would recommend dosing the first fill up with biocide to prevent regrowth. Whether to do your own tank cleaning or pay some one else depends on if you do not mind the messy work. Access to the tank could be the deciding factor. Is it a small tank that can be easily reached inside with long handled implements? If it is a large tank that must be entered, you have a whole set of safety issues. If done yourself, you can be confident in quality of the job. It must be thorough, or regrowth will happen.



I have found that along with scraping and scrubbing, a good strong degreasing detergent and hot water does the job. Then rinse with plain hot water and dry. A good marine or janitorial supplier should have a good choice of cleaning detergents. Do you have a portable pump for removing the used cleaning materials? Or perhaps a wet shop vac would be better. Of course there is the matter of legally and responsibly disposing of sludge and used cleaning water and detergent. Periodic biocide dosing can be good maintenance, or at least at off season lay up.

[2 Itchy Feet]

Originally Posted by Annabel

I hope this is in the right forum. We are returning to our yacht in Greece after the extended time of 2.5 years because of Covid (Grrrrr) we are a bit worried that our diesel may have developed a bug problem. My husband is rather convinced that we should empty the tank and replace it with new diesel. Any views on this anyone? Thank you

Great question that has been puzzling me as well. We have a full tank in a 2019 catamaran but didn’t put any biocide in at the time as we thought we would only be 6 months till next use. 2.5 years later I am wondering about this. The marina tech people said a year ago it was too late to put biocide in, so I am apprehensive!!!
If your boat is in Cleopatra Marina and you are there first week of May, look us up. 2 Itchy Feet, FP Astrea 42 currently on the hard but will be wet for a couple of days.