Portable Diesel Tank?

[MikeD]

This was suggested on the Ariel forum and I thought it was a great idea. And since diesels are much less frequent per capita on that forum, I thought I'd ask the collective here for some additional input.

I only go through 1 or 2 gallons a year, and a 12-14 gallon tank seems unnecessary. This setup seems like it would solve a few issues: stale fuel, easier cleaning, weight in the stern. And specifically for me, water ingress through a suspect fuel fill cap mounted in a silly location - the cockpit sole. Yes, I should have moved it long before, but...

Simply remove it at the end of the season and refill next season with fresh clean fuel. Just take it home and top it off mid-season. For a longer cruise, bring another tank or two.

Are there any sort of regulations concerning this?

[One Way David]

I can't answer the regulations question 'cause I don't know. I know diesel is quite stable, much more so than gas. There are occasions where people talk of this bacteria that get in it and cause problems but I have seen tractors parked for years and if no water contaminated the system, they started right up. Its rare that a gas engine will do that if fuel is not treated and /or drained. Keep the filters changed and that fixes the sediment and gunk issue.

Diesel turns a lot of people off due to the mess and smell. I can't go near a diesel engine without walking away smelling like crap. I would think the coupler that you choose would leak fuel. It's of lillte safety issue but a mighty mess and smell. A fixed system would not have that problem.

I'll sit back and listen to what others have to say.

Dave.

[Tim]

ABYC H-33 does not preclude the use of a portable tank for diesel fuel, and in any event ABYC H-33 is not a "required" standard in that it is not incorporated by reference into any legally-encorceable set of code requirements. Diesel fuel, being less volatile than gasoline, does not fall under such stringent restrictions and requirements for its storage and piping on board.

However, any tankage--and related hoses, mounting, and so forth--should meet all applicable portions of this standard in terms of labeling, hose connections, means of securing, fire resistance, etc. These aspects of the standard are too lengthy and diverse to cover in a non-specific way here, but the standards exist for a reason, and one is wise to comply with the basic suggestions at a minimum.

Beyond that, what is acceptable is up to you, and perhaps to your future insurance surveyors' opinions as to what constitutes an acceptable installation.

The easiest way to ensure tankage compliance is to use a tank specifically manufactured for use with diesel fuel, and labeled as such. What did you have in mind for your tank, specifically? Where and how would you mount it?

[MikeD]

I'm still mulling this over and haven't researched tanks or connections or anything yet.

Maybe it could be stored it in one of the lockers or the lazaret or under the cockpit sole where my tank is now. Perhaps a shelf could be built that could slide forward to gain access to the portable tank through the cockpit hatch, then slide it back under and lock it in place out of the way?

I like the idea of a lightweight, small and easily cleaned portable tank.

Beyond that, what is acceptable is up to you, and perhaps to your future insurance surveyors' opinions as to what constitutes an acceptable installation.

I take it from your reply you're not too keen on the idea?

[Tim]

I'm still mulling this over and haven't researched tanks or connections or anything yet.

Maybe it could be stored it in one of the lockers or the lazaret or under the cockpit sole where my tank is now. Perhaps a shelf could be built that could slide forward to gain access to the portable tank through the cockpit hatch, then slide it back under and lock it in place out of the way?

I like the idea of a lightweight, small and easily cleaned portable tank.

Beyond that, what is acceptable is up to you, and perhaps to your future insurance surveyors' opinions as to what constitutes an acceptable installation.

I take it from your reply you're not too keen on the idea?

You haven't given enough information yet for me to think one way or another, but assuming Micky Mouse isn't involved, and the installation is safe, effective, and generally meets applicable standards as well as the straight-face test, there should be no reason not to proceed with the concept. But you'd be wise to consider the ramifications in terms of the applicable standards if you make changes, to avoid potential issues in functionality and perceived compliance down the road--which is what you're doing by asking the question.

Now, we just need details of your proposal to suggest how well or not it does against the standards to which it might someday be held.

[Case]

Well...

I have seen pictures of people testing diesel engines outside (after working on it) and they were attached to a portable gas tank. The very same sort you use with outboards. They apparently works. I wonder about the fuel return lines but on the other hand, the diesels I saw in the pictures were old ones. Old diesels often don't have return fuel lines.

There are diesel outboards being sold out there (not in the US) so looking at tanks for those outboards might be a possibility. The best option would be getting a small plastic diesel tank and make it somewhat removable. I have seen some in the 6 gallon sizes, maybe smaller ones exist.

I have just realized something important while typing this - diesel engines must have fully bled fuel lines. Air bubbles are a bad thing and will stop a diesel dead in the water. So... aiming for a truly portable fuel tank might be a waste of time because each time you install it, you might have to bleed the fuel lines. Its a messy and nasty work. Maybe its not a problem with some newer self-bleeding diesels, though.

- Case

[sail_fix]

This was suggested on the Ariel forum and I thought it was a great idea. And since diesels are much less frequent per capita on that forum, I thought I'd ask the collective here for some additional input.

I only go through 1 or 2 gallons a year, and a 12-14 gallon tank seems unnecessary. This setup seems like it would solve a few issues: stale fuel, easier cleaning, weight in the stern. And specifically for me, water ingress through a suspect fuel fill cap mounted in a silly location - the cockpit sole. Yes, I should have moved it long before, but...

Simply remove it at the end of the season and refill next season with fresh clean fuel. Just take it home and top it off mid-season. For a longer cruise, bring another tank or two.
Are there any sort of regulations concerning this?

Might I suggest that you look at the base problem and see if it warrants this much work/anguish.
Strictly IMHO... a 12 to 14 gallon tank is already very small; a small diesel often averages about a half gallon per hour, so this is not much of a cruising range to start with.
Next, a lot of Good Old Boats have their tanks under the cockpit, and a fair number of 'em have the fill in the sole of that cockpit.
Next, after XX number of decades, it's probably time to pull and pressure-test that tank, install a new short (!) fill hose, and a new fill cap. When you do that, machine a circle of 1/4" G10, and glass that down first to raise the fill cap slightly above the rest of the sole so that no standing water will remain over it. Chamfer the edge of that G10 donut. Paint to match.

Then you're good for another couple of decades or so. Note that a lot of other boaters are jealous of your present fill system -- any little spillage can be easily caught before it makes its way into the outside water. Also, if the fill is directly over the tank, you have a back-up measuring system for your fuel... a marked stick can be inserted and read.

Note B: if using portable tanks with snap-apart fittings for fuel, you will find that diesel is a lot messier to clean up than other more evaporative fuels. The return line often carries little actual fuel, but still needs to be there, too.

Just another .02 worth.
or less with holiday discount...........
:)
L

[MikeD]

There's really not much more info on "the installation". I had water a algae in the fuel tank this year thanks to a failed o-ring on my fuel cap. This restarted me thinking about my fuel fill location.

So... aiming for a truly portable fuel tank might be a waste of time because each time you install it, you might have to bleed the fuel lines.

Good point - I've read about folks installing squeeze bulbs to assist in bleeding the lines. Is this a common practice?

Note that a lot of other boaters are jealous of your present fill system -- any little spillage can be easily caught before it makes its way into the outside water. Also, if the fill is directly over the tank, you have a back-up measuring system for your fuel... a marked stick can be inserted and read.

Actually, a stick is my primary "system" to check my fuel level. I didn't realize that this was a common place to put a fuel fill, and you also make some very good points. Also, the kids are getting old enough now and liking our "over-nighters" on the boat, and I'm hoping in the next few years we'll all be ready for some longer passages and real coastal cruising. So the larger tank may be nice to have then.

...machine a circle of 1/4" G10, and glass that down first to raise the fill cap slightly above the rest of the sole so that no standing water will remain over it.

...Been on on my to-do list along with a additional cockpit drains. Eh hem! :)

I'm much more lukewarm on the idea today, and there's probably a reason why you don't see a portable diesel tank often. Still an interesting idea which would solve a couple issues mentioned earlier with how I currently use the boat.

In the end, I suppose there's really no substitute for a well maintained and permanent system, and you could always just keep the tank partially full. The weight difference is probably not that much either.

As always - thanks everyone for your input!

[radicalcy]

I'm a bit late to this thread, but since I've had to address this problem, here goes.
I use a standard 6 gallon outboard tank with my Yanmar 2QM.
My main tank algaed up, and the fuel system clogged in the middle of Chesapeake Bay two years ago. I needed a quick fix, so after being towed to a transient marina, bought the auxiliary tank and hose, closed the petcock on the main tank, disconnected the lines at the fuel filter, connected the new lines from the 6 gallon tank, changed out filters, bled the system, and all has been good since. I removed the quick fittings and installed hose nipples. The smaller tank is installed in the cockpit lazerette and tied down with nylon straps and stainless padeyes. I have had no leaks, and the new tank is as easy , or easier to fill as the original and no worries about over filling and and fuel spills. Next time I haul out for maintenance I'll deal with the primary tank problem.

[Quetzalsailor]

By the time you mount and connect your small tank properly, it's no longer portable. There's nothing wrong with the idea of a small tank, except perhaps for convenient, spill-free filling. If you were to get your prime tank clean and filled with clean fuel, and you had a decent filter, it would not be a problem again, soon, either.

Our PO used to keep two 2.5 gal diesel jerrycans in the lazarette. I could not see the reason for that when the prime tank had 40 gallons and there was no way to independently feed the engine from the them, and I did not like the smell from the inevitable weeping from the jerrycan lids.

[radicalcy]

If there is diesel on board, there is some diesel smell....so if the little tank weeps...it weeps.
The point wasn't to make the tank portable, but rather to install a functional tank quickly and cheaply. Additionally, like many others here, I'm sure, I burn much less annually than the 20 gallons that my primary tank holds unless I'm doing an extended cruise (80 hours of engine time) so there is the issue of algae growth. I have space for two 5 gallon jerry cans in the same lazerette if I need them.
Also If I allow the larger tank to drop to less than half full, I risk introducing air into the fuel system when the fuel sloshes around exposing the pickup tube to air. The tank is original to the boat (1977) and I have no idea whether or not there are baffles installed in the tank. So, until I can find time to pump out the fuel in the old tank, and clean it, or replace it with a newer, better alternative, my $25 auxiliary tank works

[Zach]

Actually... If you have a set of glass fuel filters, racor and the like you could avoid the line bleeding by having a valve at the filter. With the engine off, turn the filter to the off setting. Put a petcock under the fuel filter in the fuel line at the quick connect. Set your tank in place, open the petcock and have a glass jar handy. Let the air out and let the diesel start to run out. Close the petcock on your fuel line, turn the fuel valve back on at your fuel filter and keep on going. Your fuel filters should hold a vacuum, and your injector pump should not bleed out the return line so the system ought to stay primed if it is in good shape.

Basically all you've done is made a day tank. Around here, the pre-historic method of a fuel water separator is a mini-fuel tank at the low point of the fuel line system. At the bottom of this tank is a petcock which you drain out a few ounces of fuel every day and prove that there is no water in your system. This might be a 50 gallon tank on a trawler, with a shutoff coming in and the return line going to the main tank (So it doesn't recirculate until the fuel gets hot, and you've only a days fuel to be contaminated if you run through the rough stuff and stir up 50 years of sediment in the main tank. Most old diesels run on a loss system where whatever fuel isn't needed by demand is sent back to the tank. Same reason why on some diesels you can hop up the injector pressure by restricting the return line...

If your fuel line doesn't gravity fill, you'd need a lift pump at the tank anyway... which just means you could use a solenoid or valve that runs back to the tank and have an automatic priming system. My opinion is a second to best installation from the start. But then I'm the kind of guy that on a tank with a fuel sender installed, will use a stick anyway....

Zach

[Zach]

Oh... The other thing you may want to think about for your fuel line if you are concerned about introducing air, is just to run real over sized off the tank from its lowest point. Think 1 inch stuff. Get within a foot or two of your engine, and reduce it down, put in a valve and run 3/8ths or whatever hose to your filter. That way you can cut off the valve on your fuel line and replace the short hose without draining the tank. These are all hydraulic lines with JIC fittings, so you can get them made up anywhere....

You can pull a 3/8ths air bubble, but it is hard not to burp air back into the tank on a large diameter hose or pipe when the demand is nil, and the engine could run for 10 minutes on the contents of that pipe or hose.

Lastly, I'd spend as much time or more on getting your ground tackle where it is easy to set. If you are reliant on your engine to get you into and out of jams in rough conditions... it'd be wise to make sure that everything is rigged up and ready. My two cents is to take the route you'd take, distance wise from shore if you were sailing while you are motoring. Everyone seems to charge into tight spots, and cut the slews when there is an engine running, while under sail its a bit more laid back and the safety factor is larger.