Fuel System Redesign

[O C Diver]

- I think on-boat polishing systems are highly over-rated. I just don't think they create enough agitation, or draw from low enough in most tanks to address the settled crud at the bottom, and that's what you really need to polish out. Any suspended crud will get filtered out very effectively by the main filters.

While I would agree with you in normal cruising conditions, when I'm rolling in 3 to 4' beams seas, everything that can get stirred up, will. The other factor is flow rate. At normal cruise, my lift pump flow rate (not fuel consumption) is about 20 GPH. The fuel polisher is about 180 GPH. I typically only polish the starboard side tank that feeds the engine and generator, when sea conditions would be stirring up any tank sediment. All fuel is loaded in the port side tank and polished as it's transferred.

The other nice feature on my setup is that fuel is returned at the opposite end (10' away) from where it's drawn, which should help to move all the fuel toward the polisher pickup.

Ted

 

[twistedtree]

Re fuel contamination, I would suggest a two step process to best protect against it.


Step 1: Thoroughly clean your tanks. All problems seem to emanate from crud that has accumulated over years and years, and that gets suddenly stirred up in rough conditions. Once clean, unless you take on bad fuel, they will stay clean for a very long time. I have seen 10+ year old tanks opened for inspection or repair that are immaculate, and the boats have been uses extensively. I think it's much, much better to proactively clean your tanks rather than put all sorts of polishers in place, wait for rough weather, and hope it all works.


Step 2: Once you have clean tanks as a starting point, quarantine purchased fuel and never let it mix with the fuel you plan to consume. This is the basis for the whole day tank concept. This requires a minimum of two tanks, one known-good to run off of, and one quarantined for purchased fuel. Then only put fuel in the consumption tank after filtering and separating out water. That way the consumption/day tank will stay clean indefinitely, and any crud that comes aboard from the doc will stay in the storage tank.


The day tank will be continually self-polishing by virtue of the engine filters and constantly circulating fuel.


If you want a way to pro-actively clean water and crud in the storage tank that you might have taken on when fueling, a "polishing" system that draws from the very bottom of the tank, filters and separates water, and returns to the same tank would be an effective way to purge crap. Then, in 10 years, inspect and clean the tank again, if necessary.


Now I realize it may not be practical to accomplish this on many boats given space, existing tanks, tank sizes, etc. But it should be food for thought.



And if nothing else, inspect and clean your tanks so you are at a known starting point. If you have a filthy tank and hit rough weather such that filters are starting to plug, I think there is a good chance that you will be flat out screwed trying to filter that out while still running, before you run out of filters.

 

[bridaus]

Re fuel contamination, I would suggest a two step process to best protect against it.

I feel like my design handles everything you just said except the initial cleaning. Good stuff.

 

[JDCAVE]

I agree, I always felt that a rolling boat was a viable way to stir up a tank, and that the next level wasn't a polishing system, but a pressure washer.



Stated another way, I don't think any return line even a dedicated one from a polishing system can match a rolling boat for stirring it up. IMO.



Lastly, I think polishing is more of a piece of mind thing. It can make a real difference at times, sure, but I bet 90% of the time it just makes us feel better. But that has value, I like feeling better, don't you?



Oh, and PS: The reasons I want to include the pump in my system are 60% for backup to the engine pump (and leaks), 30% priming convenience, 5% polishing, and 5% fuel transfer for maintenance reasons.

I replaced the filter element in my ESI polishing system (installed by the PO) after 4 years and it was completely clean. The system had been used regularly to move fuel from tank to tank, However, the regular use primary filter elements on the engine supply were needing replacement after about 500 hours. So I eventually put the ESI on the Inverter side of the panel so it could be operated whilst traveling and without using the generator.

All the above notwithstanding, I agree with TT: I would not bother installing one based on what I know now. I opened an inspection port last year and there was very little accumulation of asphaltenes on the bottom of the tank.

Jim

 

[Ski in NC]

A few thoughts:

1. Do keep the sight tubes. As soon as your electronic ones give a goofy reading, you will want sight tubes or the ability to dipstick tanks.

2. Gen and main engine should not share a supply and return. With one running and the other off, fuel (and air) can be drawn backward through the off machine and stall the one running.

3. Nothing wrong with gennie being fed from only one tank. They burn little and often are run infrequently. That is how I set mine up and many do the same.

4. If you have tank clean out ports, open up your tanks and clean them. Then a polishing system is not needed.

5. Keep it simple.

 

[bridaus]

A few thoughts:

1. Do keep the sight tubes. As soon as your electronic ones give a goofy reading, you will want sight tubes or the ability to dipstick tanks.

2. Gen and main engine should not share a supply and return. With one running and the other off, fuel (and air) can be drawn backward through the off machine and stall the one running.

3. Nothing wrong with gennie being fed from only one tank. They burn little and often are run infrequently. That is how I set mine up and many do the same.

4. If you have tank clean out ports, open up your tanks and clean them. Then a polishing system is not needed.

5. Keep it simple.

1. Good point. Though I could still manually check them with a quick manual sight gauge setup. How often do electronic gauges show funny data, and how critical is it when they do? My contention is that it's not that critical.

2. Wouldn't a check valve or two be more simple than full on duplicate lines? At some point they are going to have to tie together, I'm not drilling new holes in my tanks unless I have to.

3. Unless genny operation is considered important, and then being able to run on either tank would be valuable.

4. Reasonable, except I'm getting the polishing almost for free in terms of one tee and one valve (since pump is a given).

5. Yes.

 

[sunchaser]

Bridaus

Whether the "polishing system" is free or not, do as suggested in Ski's 1 - 5. Get everything working right and trouble free. Once up and running, you can assess the best way to install the polishing system - or if at all.

TT's comments are invaluable. Once you've cleaned your tanks out there is little chance to gunk them up unless you intentionally go looking for bad fuel. My tanks are pushing 15 years old, clean as a whistle and probably 15,000 gallons through them by now.

Lastly, if not done so, suggest you read sbarmarine's website on fuel systems and filtering. You may find a few hints on how better to set up your system as explained by a very smart marine engineer - Tony Athens.

 

[bridaus]

Bridaus

Whether the "polishing system" is free or not, do as suggested in Ski's 1 - 5. Get everything working right and trouble free. Once up and running, you can assess the best way to install the polishing system - or if at all.

TT's comments are invaluable. Once you've cleaned your tanks out there is little chance to gunk them up unless you intentionally go looking for bad fuel. My tanks are pushing 15 years old, clean as a whistle and probably 15,000 gallons through them by now.

Lastly, if not done so, suggest you read sbarmarine's website on fuel systems and filtering. You may find a few hints on how better to set up your system as explained by a very smart marine engineer - Tony Athens.

Ironically it works well now, I just don't know it well yet. Working on that. Wait until I send the pics of what it looks like though, scary. eek.

Will check out the site you mention too, thanks!

 

[bridaus]

I promised pictures...

Starboard side represented. Port side there are just the supply and return with no equipment/valving except right at the tank just like starboard.

It's all getting replaced this summer.

 

[O C Diver]

Well I haven't seen sweat copper fittings in boat fuel plumbing before. Hope somebody fired the house plummer.

Ted

 

[psneeld]

WRT sight gauges, I used Teflon tubing with self closing ball valves. The surveyor failed the original petcocks with some other ”plastic” material. Self closing valves are desirable. If your sight tubes fail in a fire, you don’t want your fuel tanks draining into the ER. The old petcocks weeped if they were accidentally left open. Transport Canada regulations call for self closing valves. Teflon has a broad operating temperature, all the way to 500 F. None of the other “plastics” come close to that temperature. Unlike glass, it’s also fracture resistant.

Teflon is a bit more opaque than the other options but is acceptable.

Original:

View attachment 85232

Replacement:

View attachment 85233

Jim

Not sure if Transport Canada thinks like the USCG, which separates pleasure regulations from commercial by a pretty wide margin.... and I second the last comment.

anyway...this was passed along to me referencing your surveyors comments....

"Again it looks like another (recreational) boat surveyor writing his own regulations. Transport Canada regulations calling for self closing valves do not apply to pleasure boats.
There are no regulations concerning the material used for diesel fuel sight glasses on pleasure boats. Self closing valves are not a requirement, just a valve that is closed when not reading the sight glass.........

.........I wish more boaters would demand "surveyors" provide written documentation that states the "regulation" they are supposedly referencing while screwing unknowing boaters."

 

[JDCAVE]

Not sure if Transport Canada thinks like the USCG, which separates pleasure regulations from commercial by a pretty wide margin.... and I second the last comment.

anyway...this was passed along to me referencing your surveyors comments....

"Again it looks like another (recreational) boat surveyor writing his own regulations. Transport Canada regulations calling for self closing valves do not apply to pleasure boats.
There are no regulations concerning the material used for diesel fuel sight glasses on pleasure boats. Self closing valves are not a requirement, just a valve that is closed when not reading the sight glass.........

.........I wish more boaters would demand "surveyors" provide written documentation that states the "regulation" they are supposedly referencing while screwing unknowing boaters."

No. For the record, I phoned the Transport Canada inspectors for information and the following is my recollection of what was said:

I asked if Teflon is approved as a material for sight tubes?

Response: No it is not.

I said but I understand that TC approves Acrylic for sight tubes and the fire rating for acrylic is lower than for Teflon.

Response: No we don’t approve acrylic for sight tubes, but we will ACCEPT acrylic for sight tubes.

Then would TC “ACCEPT” Teflon, for sight tubes?

Response: yes, we would “ACCEPT” Teflon as a material for sight tubes. And...the installation MUST HAVE SELF CLOSING VALVES on both sides of the tubes.

So the hangup was on the choice of words, ACCEPT is different than APPROVE.

So why did I phone Transport Canada? Because my surveyor insisted I phone them because he thought that someday my boat might be subject to TC “Steam Ship” inspection because I have a commercial fishing license on it. Evidently TC is considering more stringent inspection of smaller fishing vessels that are currently exempt. Why didn’t my surveyor phone TC or know this? I don’t know. Lazy? Perhaps. All I know is he had a definite bee in his bonnet over my original sight gauges and he insisted on an acceptable revision of my system based on what the Transport Canada inspector thought was acceptable. NOT what AYBC thought was acceptable.

“Again it looks like another (recreational) boat surveyor writing his own regulations.” No. This is not the way it was or is. I inquired with Transport Canada and the above is what they said. My installation would be acceptable based on the above paraphrased conversation.

Jim

 

[JDCAVE]

Further to this topic:

https://laws-lois.justice.gc.ca/eng/regulations/SOR-90-264/page-15.html

“Marine Machinery Regulations (SOR/90-264)
Fuel Oil Systems”

“14 b) for ships certificated to carry 12 passengers or less, the system may include the use of oil-level gauges with flat glasses and self-closing valves between the gauges and the oil tank, but may not include the use of cylindrical gauge glasses.”

Teflon isn’t glass.

 

[Wxx3]

Some random thoughts....


- I'd keep the sight gauges, but renew all the fittings and tubes, and install self-closing valves at the bottom.


- I think the single biggest improvement you could make would be the addition of a day tank. The goal is to isolate purchased fuel from fuel that you run on, and only replenish the day tank via a transfer filter. But I understand that might not be practical.


- I'd keep the on-engine pump


- Run dedicated feeds to each engine - nothing shared.


- For the returns, I personally like valves, but I remove the handles so a tool is required to operate them. The biggest issue I have encountered with no return valves is back siphoning when changing fuel filters, and uncontrolled fuel escape. This might not be a big issue depending on the exact plumbing, but even the residual fuel in the return line and be a lot of fuel dumping out when you unscrew a filter.


- I'd leave the inspection plates as they are.


- I think on-boat polishing systems are highly over-rated. I just don't think they create enough agitation, or draw from low enough in most tanks to address the settled crud at the bottom, and that's what you really need to polish out. Any suspended crud will get filtered out very effectively by the main filters.

I agree with TT most of the time, 99% in fact.
But my fuel polish system has kept me running when I needed to keep running.
Also, I use with whenever I buy fuel to check the fuel I bought, while at the dock. I may run it for 4, 12 or 24 hours depending.

It doesn't get more simple than sight tubes. Other measuring systems are simply not as accurate or as instantaneous.
I don't understand the drama about return valves.
Each tank should have a feed and return ball valve. That way you know exactly what is going on.

I also disagree a bit about day tanks. My engine likes cool fuel, not hot fuel. How do I know? It told me so over the last 20,000+ miles