Fuel Polishing onboard

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Man these are some nice clean setups you guys are posting pictures of .:thumb:
I ain't gonna be posting any pics of mine :nonono:
 
twistedtree said:
Because of all this, I seriously doubt that most boat polishing systems provide any real benefit that is not also provided by your main filters and the engine constantly circulating fuel. That will remove suspended impurities just as well as a polisher using the same pickup and return ports on the tank.
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Having bought into Bill Parlitore's (Passagemaker) crusade years ago on the virtues of "fuel Polishing, I have had two systems on two different boats. The last one was set up exactly as Twistedtree has outlined. The fuel was picked up on the bottom of the tank (actually in a little pocket below the bottom) & the flow rate was sufficient to scour the bottom of the tank. In the 10 years since that last polishing system & with a considerable effort to investigate said polishing systems, I have arrived & completely agree with the comment made by twistedtree. At best, most polishing systems I've looked at (not all) are no more than and extra layer of filters and a fuel transfer system. In my case, my Yanmars (440s) return fuel to the tank at a sufficient rate to guarantee that the fuel in the tank is turning over (being filtered again) more often than one would imagine. (Not polished, just filtered again.) There was quite a bit of dialogue on BoatDiesel about this very subject last year.:blush:
 
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While by strictest definition mine may not be a fuel polisher, I'm really more after cleaning the lowest corner of the tank where the water and impurities settle out to. My tanks slope from outboard to inboard and from stern to bow. All but the last few ounces can be drained from the port where the polisher is connected. IMO, keeping the bottom of the tanks clean and being particular about where you buy your fuel, is 99% of the clean fuel battle.

Ted
 
O C Diver said:
keeping the bottom of the tanks clean and being particular about where you buy your fuel, is 99% of the clean fuel battle.
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Thank you for finally making this point. Certainly, dirty fuel can be cleaned, but if your tanks are dirty, what difference will it make? Keep you tanks clean. Then, keeping your fuel clean (or as the case may be, regular cycling thru a filter system... call it polishing if you like) won't be needed. Your regular filters will do their job.

*I acknowledge the fact that not everyone has the access to their tanks to have them professionally cleaned. Therefore in this case, something is better than nothing.
 
Sunchaser alluded to the fact that the additive package that is in the fuel can be degraded over time, is there someway to test this, and to restore the additives when needed?
 
mramoo said:
Sunchaser alluded to the fact that the additive package that is in the fuel can be degraded over time, is there someway to test this, and to restore the additives when needed?
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There is a simpler approach, use the boat. Nothing good comes from letting fuel sit for years. Use the boat and strive to consume the fuel in the tank a couple of times a year. If the capacity of the tank is more fuel than you would use in a year, don't fill it all the way.

During my refit, the fuel in my tanks sat for 2 years. Some impurities settled out of the fuel and were filtered out through my polisher, but there wasn't any problem with the fuel. Going forward, the fuel will turned over several times a year and lublicity etc. just won't be an issue.

Ted
 
mramoo said:
Sunchaser alluded to the fact that the additive package that is in the fuel can be degraded over time, is there someway to test this, and to restore the additives when needed?
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I actually kinda doubt it. The diesel expert (non-active member here) has repeatedly presses the idea to me (he is my tank cleaning guy too in North Carolina) that using additives is not a good idea, considering you never know what all the previous storage and handling companies have added upstream. The bestlyest<!> way to keep fuel and tanks clean is to only buy what you will use in any given 30-60 day period. And buy from a source that is A) busy and B) has a regular tank cleaning schedule.
 
Whether a polishing system will help is, IMO, dependent on your engine types. Some engines will return several times more fuel to the tank than is burned.


That filter the fuel all the time. If you buy a used boat with uncertain history then a commercial service might be a good idea, once. From then on simply run the fuel low from time to time because when fuel is low it is circulated much more frequently through the filters. A day sloshing around with low fuel in a few foot waves will stir up the bottom of the tank.


The clear filter bowls are great for judging the cleanliness of the fuel.
So start by understanding your engine fuel system before spending unnecessary money.
 
Forgetting for a moment the overhyped boat store additives like stabil, startron or valvtec the only industrial additives I'm aware of are well upstream of the end user guys like us. In one case I know of badly fouled tanks on a larger vessel needed fuel supplier and refinery assistance for proper use of industrial biocides during external fuel polishing.

The large fuel farms I've been involved with routinely check incoming fuel for cetane, water, dirt, sulfur, density and flashpoint. These are contractual arrangements made by buyer with refiner and shipper.

OCD and others have nailed it - buy boat diesel from the right seller, use it and keep your filter changes up to date. BTW, buying from the back end of Joe's clapped out delivery truck introduces a few new questions.
 
Great post by Twisted. Makes a lot of sense to me.

I have a fuel transfer line that connects to the side of each tank right at the bottom. It has a transfer pump connected to it. I have been considering adding a filter/water separator to that line so that when the fuel is transferred, it gets filtered in the process. Definitely not a polishing system, but a chance to catch and filter out any water or crud that may be hanging out on the bottom of the tank. The pros are that it would be relatively cheap and easy to do. The cons are that it wouldn't be terribly effective.

I do need to install a timer on my fuel transfer switch somewhere. I have a spring loaded toggle on the console that drives the transfer pump. Hold it to port to transfer to the port tank, hold it to starboard to transfer to the other tank. It is a pain to hold that switch long enough to transfer a significant % of a 200 gal tank. I am thinking of replacing it with a non-sprung but lit toggle and then put a timer in the ER near the pump. I have to open up the valves in the ER anyway to transfer the fuel.
 
sunchaser said:
OCD and others have nailed it - buy boat diesel from the right seller, use it and keep your filter changes up to date. BTW, buying from the back end of Joe's clapped out delivery truck introduces a few new questions.
Click to expand...

Yes it does, but some don't always have a choice between good times and good locations for purchasing. Easy for those who only cruise populous boating heavy cruising grounds and only in peak season.
 
twistedtree said:
I think the best defense against bad fuel is to have some sort of fuel segregation policy where possible given the boats tankage. Purchased fuel goes in one place, and fuel to burn goes someplace else, and never the two shall mix - except via transfer through a filter and water separator. You can call it a day tank, but I think there are other ways to accomplish the same thing without a specific day tank. But it's all highly dependent on your boats configuration.

But segregating purchased fuel and burn fuel doesn't absolve you of the need to monitor and keep the purchased fuel tank clean, and so brings us right back where we started. But al least bit keeps the crap away from the engine, which I think is priority one!
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Well said. I certainly hope you're right because this is the approach I intend to take. We have a third, aft, 200-gallon tank (that had better last more than a day) that I plan to draw from exclusively while underway. The fuel that goes into it will be filtered each day. The tank is relatively easy to inspect, draws from a sump at the very lowest point and whatever doesn't get used, will get pumped back into the storage tanks rather than sitting for weeks at a time.
 
I suspect Joes old ratty truck delivers cleaner fresher fuel than the local marina where it sits for a while.
 
We have the ESI system. All pickups from the bottom of the tanks. We typically move fuel from one tank to another, polishing fuel in the process. When refuelling we transfer the remaining fuel to the forward tanks and fill the aft ones. We typically drawn from the forward starboard tank.

ImageUploadedByTrawler Forum1465358301.795740.jpg

ImageUploadedByTrawler Forum1465358527.408090.jpg


sunchaser said:
So here is the question - is a setup of off engine filters, valves, vacuum gauges and in some cases manufacturer decals really polishing or just good marketing?
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I agree. It's pretty impressive but I don't think I'd pay the big bucks to install one.

Jim
Sent from my iPad using Trawler Forum
 
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Nice setup JD. You gave it some thought and put it together to address the specifics of your vessel.

Can you dip your tanks to assess what if anything is lurking on the bottom? Shouldn't be anything I'd guess with your setup.
 
"The tank is relatively easy to inspect, draws from a sump at the very lowest point"

The usual draw from the sump at "the very lowest point" is to remove water and crap in the fuel that will settle there.

6 inches higher has a better chance of only picking up clean fuel.

IF all fuel tanks were built with good sumps , (that were serviced) there would be almost no need for fuel polishing.

A box for fuel instead of a marine fuel tank is cheaper to buy/install for the boat assembler..
 
FF said:
The usual draw from the sump at "the very lowest point" is to remove water and crap in the fuel that will settle there.

6 inches higher has a better chance of only picking up clean fuel.
Click to expand...

Agree -- for storage tanks. Since this is a day tank where filtered fuel will only be put in a day or so before it's used, and the tank can be fully emptied afterward, there should be no opportunity for crud to form. We'll see how it works.
 
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twistedtree said:
Just because a system has an extra filter and a pump doesn't make it an effective polishing system. Some key features that do help are:

- fuel pickup from the very bottom of the tank. This is where water and other guck will settle, and if you system can't pick it up then it's doing no good. Dip tube pickups are typically designed to have exactly the opposite characteristics and intentionally pick up from a point above the guck. Most of the Nordhavn I have seen work this was and as such are advertised as transfer systems, not polishing systems.

- a fuel return location and fuel flow rate that will actually cause some agitation in the tank. This will stir up settled gunk so it can be sucked through the polishing filter. Most builtin polishers do not accomplish this as all since they use the normal top of tank return port. But this capability is really only important to rectify a long accumulation of gunk, and if you have such a situation, a polishing service should have the necessary equipment with return hoses that can be directed to different areas in the tank.

Because of all this, I seriously doubt that most boat polishing systems provide any real benefit that is not also provided by your main filters and the engine constantly circulating fuel. That will remove suspended impurities just as well as a polisher using the same pickup and return ports on the tank.

I think the best defense against bad fuel is to have some sort of fuel segregation policy where possible given the boats tankage. Purchased fuel goes in one place, and fuel to burn goes someplace else, and never the two shall mix - except via transfer through a filter and water separator. You can call it a day tank, but I think there are other ways to accomplish the same thing without a specific day tank. But it's all highly dependent on your boats configuration.

But segregating purchased fuel and burn fuel doesn't absolve you of the need to monitor and keep the purchased fuel tank clean, and so brings us right back where we started. But al least bit keeps the crap away from the engine, which I think is priority one!
Click to expand...

I rarely polish fuel unless the tank level is down to the last 20 or 30 gallons and we're out in a seaway. We've burned thousands and thousands of gallons but probably have collected a total of a teaspoon of gunk in the Racor bowls over the years. The rest of it is trapped by the filters. If you burn your fuel load in a couple of months you probably aren't going to benefit from a polishing system. If you carry it for a couple of years or refuel from 55 gallon drums someplace you will, IMO.
 
sunchaser said:
Nice setup JD. You gave it some thought and put it together to address the specifics of your vessel.

Can you dip your tanks to assess what if anything is lurking on the bottom? Shouldn't be anything I'd guess with your setup.
Click to expand...

Ted: The PO put this system in after he replaced the tanks. I have inspection ports but I haven't dipped the tanks at all.

One approach to "fuel polishing" would be to move most of the fuel to other tanks and when the tank is near empty, set the "return" valve to have the fuel return back again to the tank being polished, thereby creating agitation to the remaining contents in the tank.

Jim
Sent from my iPad using Trawler Forum
 
"have the fuel return back again to the tank being polished, thereby creating agitation to the remaining contents in the tank."

Even 30 GPH of a Detroit being returned will not agitate the tank as much as falling off a wave, just once.

Fuel polishing may be great fun , but it does not clean a fuel tank.
 
My particular 'fuel polishing' system involves a Perkins 8 GPH fuel return line sucking from/ returning to one tank at a time. One day the port, The other day the stbd. Keeping fuel onboard to a conservative minimum (anticipating Fuel needed.) Last summer I used the boat 30 gallons/hours. So it pumped 240 gallons of fuel. I only have 50 gallons aboard. So the fuel was filtered(polished) to 2 microns approximately 4.5 times.

Agreed that an afternoon sloshing around in a seaway does more to 'loosen up' in tank crud than any polishing system.

Probably the most important tool in the box to figure out fuel tank/filter sludge status is a fuel vacuum gauge.

On my boat the engine runs normally around 2 lbs vac.

When the fuel line shows 7to 8 lbs vac the engine stumbles and hunts.

At 10 it shuts down. Ask me how I know this......

I learned this in delivery in the middle of Lake Erie.

Two summers ago I went through around 18 fuel filters after I bought the boat. The fuel ( 150gl) had been onboard for around 3 years. And I burned about 130 gallons on delivery.

Now two years later the tanks are clean. And I change filters once a year.
 
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