Simple DIY diesel scrubbing?

[Piers]

Why do you say "well above the tank's base"?

If the pick up is close to the base, the filter could become blocked quickly leading to a start/stop operation. Plumbed in the way described allows time for everything to be stirred up and filtered bit by bit rather than lump by lump.

 

[chuzzlewit]

If the pick up is close to the base, the filter could become blocked quickly leading to a start/stop operation. Plumbed in the way described allows time for everything to be stirred up and filtered bit by bit rather than lump by lump.

Mmm. Not fully convinced. Each season I poke a tube to the bottom of the tank and suck out about 20 litres, let it settle and then pour it back except for about half a cupful which contains a few black specks. Nothing clogs up. It struck me that a permanent pipe ,pump and filter would save time and mess.

 

[Piers]

Mmm. Not fully convinced. Each season I poke a tube to the bottom of the tank and suck out about 20 litres, let it settle and then pour it back except for about half a cupful which contains a few black specks. Nothing clogs up. It struck me that a permanent pipe ,pump and filter would save time and mess.

Morning C. OK, the full answer about the piping is:

1. To ensure everything is loosed and picked up from the tank base, you need to create a strong swirl, rather like a whirlpool.
2. This requires the pump's outflow piping to be parallel to, or at least angled at the base - not pointing at it.
3. If the pick up tube is too close to the outflow it's likely that you'd stand a chance of short circuiting the process by picking up mainly from the outflow rather than the tank's contents.

An issue in tank construction is that baffles are often installed to prevent fuel from surging whilst travelling. Muck can easily hide behind these baffles. hence, in tank construction, piping should (in a perfect diesel tank world) have multiple outlets, each ensuring nothing can hide.

 

[John100156]

All above are good points to consider and its good to consider all arguments so an informed choice can be made.

When a boat has a bug issue, marine engineers often use a similar set-up (likely more powerful) whilst on berth to clean the fuel but its best if they can also get to look in and clean the tanks , well lets face it, who wants to take a boat out with the bug in it.

I suppose on balance my thinking is: it must be beneficial to polish the fuel even if only local precipitated contaminants are removed and even if only from the bottom of the tank and I need to change the polishing filters a few times, after all, it will have mitigated some of the risk for when the fuel is stirred up again at sea, hopefully the active motion of the fuel in the tanks may keep the baffles reasonably clean. I don't know this, just reasoning on it.

I would like to try this at some stage in the future, as I have really good access to drain points on both my tanks. If I do, I may buy a couple of Separ filter units for polishing, then I could use them to add to my single units already in place at a later date.

Its all low down on my list as M16 seems to be working really well but a fun and interesting project.

 

[Hurricane]

This word "polishing"
IMO, It MUST have been dreamed up by a salesman wanting to sell a filter and a pump.
What tosh!!

 

[Portofino]

The rtn rate varies, it’s got a huge range within the same motors depending on the load and it varies between engine brands depending on the injectors .
Numbers seem to be as low as 10 % on idle up to 80 % with CR running at a healthy cruise say 80 % load .

So Hurricanes assertion has merit .
Consider this a typical Med scenario .
A bit of touring about for about a week or so , 3-4 hrs / day .
Using my own numbers an a arbitrary 50% rtn , .....800 L tanks for each motor ( 1600+ 600 long range total ) .
Sort of 2/3 full so 600 L , it’s a 4 hr trip to first port of call .
@ 80-90 L per side with a pool of 600 L to play with / side , and 50 % rtn this means 320-360 burnt but 1/2 that amount rtn d .
So 160-180 has been sent back in the remaining end of day 600 - 320/360 which makes more or less the majority has been through the first day .
So whats sat in the tank has been “ polished “ or gone through my centrifugal racors .@ 30 micron then a pair of in series 2 micron spin on type on the motors ...that’s 3 filters .

Tomorrows another day , a short day to a bay 1/2 hr away for lunch n swim , so another 1 hr running @ cruise .
The remaining 250 L or so .....80-90 used 45 @ 50 rtn rate is recycled , the pot is now 150-180 time to fill up .

Next day time to move on so a visit to the fuel pontoon to take on 500 L of fresh into each tank .....taking them to 650 .
Another 4 hr trek , another 350 L disappears another 175 returned ...levels now at 300 ish ....so every day it’s just going round + round + being topped up with fresh every other for 4/5 days .By day three I think it’s all been through by now .
If the rtn rate is higher nearer 80;% then it’s all been through on day 1 .

Surely with clear bowls + £10 filter elements, you would notice if the racors were fogging up and for the sake of £10 inquisitively just change out a filter to check for any muck ?


I have accessible tank drains and never noticed any muck .
Reason is last year we did 80 hrs mostly on 1/2 to 2/3 tanks .
I tend to dose up anyhow with what ever anti bug local chandlers stock.....either the water dispersant or antimicrobial ...not fussed .
Basically if you run your boat it’s filters recycle the fuel so much it’s pointless adding anything else .

Just pull a cartridge out and take a peek , if any doubts stick a new one in .

 

[John100156]

This word "polishing"
IMO, It MUST have been dreamed up by a salesman wanting to sell a filter and a pump.
What tosh!!

Yep, 'polishing' is also a term used in every laboratory in the UK, when installing water treatment equipment (RO/Milli-Q/Ultra-Pure) which is in essence, comprises filters and a pump ;-)

 

[John100156]

The rtn rate varies, it’s got a huge range within the same motors depending on the load and it varies between engine brands depending on the injectors .
Numbers seem to be as low as 10 % on idle up to 80 % with CR running at a healthy cruise say 80 % load .

So Hurricanes assertion has merit .
Consider this a typical Med scenario .
A bit of touring about for about a week or so , 3-4 hrs / day .
Using my own numbers an a arbitrary 50% rtn , .....800 L tanks for each motor ( 1600+ 600 long range total ) .
Sort of 2/3 full so 600 L , it’s a 4 hr trip to first port of call .
@ 80-90 L per side with a pool of 600 L to play with / side , and 50 % rtn this means 320-360 burnt but 1/2 that amount rtn d .
So 160-180 has been sent back in the remaining end of day 600 - 320/360 which makes more or less the majority has been through the first day .
So whats sat in the tank has been “ polished “ or gone through my centrifugal racors .@ 30 micron then a pair of in series 2 micron spin on type on the motors ...that’s 3 filters .

Tomorrows another day , a short day to a bay 1/2 hr away for lunch n swim , so another 1 hr running @ cruise .
The remaining 250 L or so .....80-90 used 45 @ 50 rtn rate is recycled , the pot is now 150-180 time to fill up .

Next day time to move on so a visit to the fuel pontoon to take on 500 L of fresh into each tank .....taking them to 650 .
Another 4 hr trek , another 350 L disappears another 175 returned ...levels now at 300 ish ....so every day it’s just going round + round + being topped up with fresh every other for 4/5 days .By day three I think it’s all been through by now .
If the rtn rate is higher nearer 80;% then it’s all been through on day 1 .

Surely with clear bowls + £10 filter elements, you would notice if the racors were fogging up and for the sake of £10 inquisitively just change out a filter to check for any muck ?


I have accessible tank drains and never noticed any muck .
Reason is last year we did 80 hrs mostly on 1/2 to 2/3 tanks .
I tend to dose up anyhow with what ever anti bug local chandlers stock.....either the water dispersant or antimicrobial ...not fussed .
Basically if you run your boat it’s filters recycle the fuel so much it’s pointless adding anything else .

Just pull a cartridge out and take a peek , if any doubts stick a new one in .

Just to play devils advocate a bit:

This may well be true but despite much recirculating it did stop Mikes relatively new P67 on one occasion despite I suspect a high turn-over of fuel and he does treat his fuel, so it can still creep in through marina tanks - on balance, I cant see any reasonable arguments not to try 'Polishing' (sorry Mike filtering) and possible benefits, albeit minor?

 

[John100156]

Come on then - we all understand the 'POSSIBLE' benefits, other than cost, terminology and buggering about setting up, what are the detriments?

 

[Portofino]

Come on then - we all understand the 'POSSIBLE' benefits, other than cost, terminology and buggering about setting up, what are the detriments?

None .
But still pointless if you use your boat .

 

[John100156]

Not so sure, I cite those reasons above and even IIRC Mark (Elessar) had the bug and stopped en-route from Vinaros(?) to SCM in his Sealine, albeit probably untreated and the boat had sat idle for a while.. .Therefore I see nothing detrimental and possibly some benefits....

Anyway, we have debated it in good spirit and people can make an informed-ish choice.

I am bound to try it though as my boat does not go out as much as others, due to work commitments, its low down on my list (new filters arriving at the boat from our friendly supplier in SC on the 8th), time is a precious commodity I have very little of...!

 

[Rocksteadee]

Not so sure, I cite those reasons above and even IIRC Mark (Elessar) had the bug and stopped en-route from Vinaros(?) to SCM in his Sealine, albeit probably untreated and the boat had sat idle for a while.. .Therefore I see nothing detrimental and possibly some benefits....

Anyway, we have debated it in good spirit and people can make an informed-ish choice.

I am bound to try it though as my boat does not go out as much as others, due to work commitments, its low down on my list (new filters arriving at the boat from our friendly supplier in SC on the 8th), time is a precious commodity I have very little of...!

IIRC from PBO article it takes 4 days for any treatment to fully work (Initially 2/3 work done in 1/3 of time). Fresh contaminated fuel could have stopped boat as would have taken a day and half to have mostly treated fuel

 

[Hurricane]

IIRC from PBO article it takes 4 days for any treatment to fully work (Initially 2/3 work done in 1/3 of time). Fresh contaminated fuel could have stopped boat as would have taken a day and half to have mostly treated fuel

Not quite sure what you are saying here.
But, IMO, it takes a day or two for contaminated fuel to get a hold and the bug doesn't grow in the whole tank - only where there is water (usually at the bottom).
So, IMO, dising every delivery of fuel stops it from even starting to grow.
And my experience is that you only need a very small amount of treatment to cover a lot of fuel.
My tanks are 2000 litres each side (a main tank and a wing tank each side).
Every time I fuel up, I put 100ml of Marine 16 in each side.
This dosage assumes that the tanks are empty - which, of course, they aren't so I am, effectively, over dosing.
But the cost of this treatment is very small in comparason to the cost of the fuel.
Its a "no-brainer" and, in reality, it keeps the bug away.

 

[Rocksteadee]

Not quite sure what you are saying here.
But, IMO, it takes a day or two for contaminated fuel to get a hold and the bug doesn't grow in the whole tank - only where there is water (usually at the bottom).
So, IMO, dising every delivery of fuel stops it from even starting to grow.
And my experience is that you only need a very small amount of treatment to cover a lot of fuel.
My tanks are 2000 litres each side (a main tank and a wing tank each side).
Every time I fuel up, I put 100ml of Marine 16 in each side.
This dosage assumes that the tanks are empty - which, of course, they aren't so I am, effectively, over dosing.
But the cost of this treatment is very small in comparason to the cost of the fuel.
Its a "no-brainer" and, in reality, it keeps the bug away.

Not my clearest writing.
The gist was supposed to be that you had taken on the bug when refuelling from a barge/ bowser where it had already developed and your own treatment would not have cleaned it up for a couple of days

 

[NealB]

Just wanted to say "thank you!!" to all contributors to this thread.

It's been very informative (I've learned a lot), and it's deeply relevant to me right now.

 

[John100156]

Yes good debate in good spirit

Mike remember each 100ml increases the volume of fuel in the tank by 100ml so don't forget to offset the cost of M16 against the cost of deisel.......

Lots of M16 in Panole, so will be going into my tanks and filling up once out there.... left them half full last visit as expected to be out again, think of all that condensation, yikes...

 

[superheat6k]

My preference is to draw through the filter and then to the pump. The pump quite violently smashes any water droplets into tiny patticles that can then pass though a sedimenter filter.

I have instant connectors on my boat so I can hook my polishing unit to either tank pickup line, drain point or spill line. I can move fuel between tanks, blowback any blocked pick ups and prime my Racors. I have never suffered contamination issues, but that said not only do I polish, but I also keep the filler tank cap threads thoroughly smothered in water proof grease. I don't bother wedging the tanks for winter as I personally believe the condensatiom in partially fileld tanks theory is just that, and does not happen with any signifciance in practice.

 

[Hurricane]

When we had the bug problem, I bought a complete water separator assembly with the aim of using it during the cleaning process.
Actually, I didn't use it.
I just pumped/circulated the fuel that was in the tanks at the time in an attempt to mix the Marine 16 up as much as possible.
Usually, we use a few tank loads each year so there is a better that average fuel turnover on our boat.

I can't remember if I mentioned it but the first load after our bug issue was treated with the Marine 16 Complete treatment.
They say that the Complete lubricates injectors and pumps etc and provides a more efficient fuel burn.
But we have only used it that once.
Maybe I should treat the system to a dose of Complete again.

 

[John100156]

I have looked at Complete too Mike, but on balance, I have never had any problems and rigidly stick to treating anyway with M16, unless I know I am going to burn all the fuel on a single day/run but even then, I would most likely treat, for me its a no brainer, its not that expensive...!

As you know, I don't turn-over anywhere near the fuel of you/others (18m to retirement though!) and have never had any issues. I am concerned because my tanks lie dormant sometimes for months, as is the case during C-19.

I like the simplicity of Superheat6k's, set-up.

I will definitely at some stage set-up something along those lines, probably adding suction and discharge gauges just for fun and using Hanson or equivalent quick couplers (I like that idea) and probably solid or even Goodridge steel braided fuel lines and fittings, without the marine tag. I used them many times on brakes and fuel lines when I prepared my rally car(s) soooo long ago now. We often re-shelled cars in SODS and MK and District Motor Club (which doesn't say much about our abilities)..... Aaaaah those were the days,,,,,,

 

[John100156]

I personally believe the condensation in partially filled tanks theory is just that, and does not happen with any signifcance in practice.

Agreed, you will understand the psychrometrics and how many milligrams per kg moisture is actually in the air in the tanks in the Med and would be likely to condense on surfaces below dew-point inside, to what are in the main, well insulated tanks - but, DONT TELL THE OTHERS... ;-)