Gas v/s diesel for trawlers

[Hidro]

Something I didnt see in this thread is the addition of alcohol in the gasoline. 10% here now, 15% on the horizion. Alcohol, water, gasoline...It is a real headache even with Racors.

 

[Art]

If I were to engage in the technical aspects of this discussion on either side it would be equivelent of Goofy sitting in on a strategy meeting of Amazon.com's board of directors. I would contribute nothing of value and be perceived as an even bigger goof than I already am.

Marin, well said! - - > Ditto - Here!

 

[Marin]

....erhaps you can ask them if trailing a wind turbine behind the 787 or windmilling an engine to turn the generator will contribute to increased efficiency and reduced fuel burn.

The only direct observation I can bring to this is I was on a Lauda Air 777 production test flight in the late 90s when Lauda was considered one of the world's best airlines. Niki himself was flying the plane as part of his 777 checkout, which is why we were on board.

One of the items on the the test checklist was the rat. The rat is a ram air turbine, aka "ptopeller-on-a-stick" which drops out of a compartment in the fuselage in the vicinity of a wheel well. The propeller, which is about five feet long, is then turned by the slipstream and turns a hydraulic pump or generator or both to provide minimal electrical and/or hydraulic power in the event of a complete loss of engine and APU power during flight. This provides the flight crew sufficient control of the plane to get it down and land it.

When the rat was deployed on this flight I was amazed at the vibration and noise it made. Since the rat cannot be retracted in flight it remains down for the duration of the flights that conduct this test. Even on the flight deck of a big 777 its vibration and snarling sound were very apparent.

I don't know how much power this thing is capable of generating nor do I know what the parasite drag penalty is of having it out there. But if the vibration it produces is any indication at all, the penalty would seem to be significant.

With regards to boats, we have freewheeled a propeller for a short time (our shafts have to be tied off if we shut down an engine). I was in the engine room frequently monitoring the temperature of the shaft log as my wife ran the boat on the other engine. We ran the working engine at the same rpm we always do. The boat's speed dropped to about six knots from eight but what I noticed was that the freewheeling prop and shaft did not turn very fast. Not as fast as the powered shaft beside it at any rate.

The 1650 rpm of our engines is fed through marine gears of 1.9:1 and 2.1:1. So that would mean the shafts are normally turning about 825 rpm. So the dragging propellor would be turning at less than that rpm. And if it was turning a generator with a load on it, the shaft rpm would be even less.

So my question is would a generator turning at what in essence is the idle speed of the engine (or slower) produce enough energy to "cancel out" the drag penalty of the unpowered propellor?

Because if it doesn't then it's a wash with what would seem to be no overall benefit or perhaps even a penalty. If it does produce more energy than what is lost to the dragging prop, then I can see it could be worthwhile in the "something is better than nothing" sense.

 

[SomeSailor]

What if you went one step further and used a single engine vessel with the electric drive system in series with the main diesel engine then both would operate more efficiently. Right?

That would the perfect scenario. Get a single engine hull... turn the engine around and mount a 100KW Perkins genset in it's place. Replace the transmission with a large electric drive motor. Find a few Prius nickle hydride packs and you could have yourself a diesel-electric hybrid. The problem is all those goodies and speed controllers and wiring would set you back about what a new boat would cost.

Definitely not a smart investment, but would be a fun project if money wasn't an object.

 

[BruceK]

The only direct observation I can bring to this is I was on a Lauda Air 777 production test flight in the late 90s when Lauda was considered one of the world's best airlines. Niki himself was flying the plane as part of his 777 checkout, which is why we were on board.

One of the items on the the test checklist was the rat. The rat is a ram air turbine, aka "ptopeller-on-a-stick" which drops out of a compartment in the fuselage in the vicinity of a wheel well.

OT, but here goes. I flew many times with Lauda, Sydney-Vienna on 767 and 777. Great service. Lauda, never in uniform, was pilot several times; crew said the plane went faster with him on board. We were never troubled by a rat (topic now justified). Lauda were early long haul users of both planes, it was a our loss when Austrian took over and later dropped the route.

 

[jeffnick]

5 gallon bucket 3/4 filled with 95% gasoline (pure or ethanol included) and 5% Toluene. Let set for 24 hrs mininum. Pick up carb and turn in mixture many times as well as holding above and letting fluids flow out then again refill by turning over and over inside mixture.

Mixture turns tan/brown color with dissolved gunk and varnish. Place carb back on motor and pour colored mixture into a car or truck tank that already has bout ½ or more fill. Disolved gunk/varnish have no effect when diluted and toluene will simply help keep fuel system clean. Drive, errrr boat on! Use good quality rubber gloves while working in the gas/toluene mixture.

I was a gravure printer by trade. Tolusol was the thinner for our inks...we used hundreds of gallons a day. I had access to unlimited quantities. I tried it as an octane enhancer in my old truck, cleaning agent, stove fuel and other things, ultimately abandoning most efforts. One thing I learned is that toluene will swell most rubber compounds. I'm not saying that 5% will cause problems, but because some is good, doesn't mean more is better. If you have a rubber component to your needle/seat, keep that in mind.

As far as rubber gloves - it's a good idea, and today breathing filters are used for press cleanups. In my day, we had the stuff running down our arms and soaking our shirts, not to mention the highs we got in confined spaces...but I'm pushing 70 and still kicking.

Finally, if you've gone to the trouble of taking the carb off your motor, you might as well disassemble it for cleaning?

 

[psneeld]

ethanol gas is actually a good varnish stripper in itself...the major problems occur when you first switch over and the ethanol starts stripping and clogging filters or when you store it long enough/let water mix so that it phase separates.

 

[FF]

The other problem was ethanol actually takes apart some internal GRP fuel tanks.

Since one side of the tank is the HULL, this is a consideration.

Custom bladder tank lining is simple effective but far from cheap solution.

 

[Art]

I was a gravure printer by trade. Tolusol was the thinner for our inks...we used hundreds of gallons a day. I had access to unlimited quantities. I tried it as an octane enhancer in my old truck, cleaning agent, stove fuel and other things, ultimately abandoning most efforts. One thing I learned is that toluene will swell most rubber compounds. I'm not saying that 5% will cause problems, but because some is good, doesn't mean more is better. If you have a rubber component to your needle/seat, keep that in mind.

As far as rubber gloves - it's a good idea, and today breathing filters are used for press cleanups. In my day, we had the stuff running down our arms and soaking our shirts, not to mention the highs we got in confined spaces...but I'm pushing 70 and still kicking.

Finally, if you've gone to the trouble of taking the carb off your motor, you might as well disassemble it for cleaning?

Yo, Jeff - Toluene was my friend too, by the 55 gal drum for about a year, when I was pretty young. Used it in many ways for fiberglass boat building in a Maine factory. I fell in love with that caustic “Big T” liquid as to what it could liquefy and clean up. Bad ass stuff on its own, at 100% pure. I too had it dripping down my hands/arms some times... probably not as much as you though, as it appears I didn't work closely with it for near as long. But, since my first encounters I’ve used it for cleaning purposes, when needed. In the enclosed "chopper gun" FRP areas the fumes would put cha on da moon. I've seen guys pulled out of draped hull confines by their feet and propped against an open outside door till they were able to talk/walk properly again. Back when... we thought that was funny. Basic rule was we were not supposed to stay "chopping" or in areas where Big T was present for more than 15 minutes, but we'd push that bubble way out sometimes.

Anyway - With taking only four main bolts and a couple clips/hoses off to place carb in a bucket for a 5% "Big T" to 95% gasoline solution to strip/liquefy the varnish and gunk out of an old carb’s interior is simple and easy and greatly reduces time-effort for basically same end result without disturbing gasket seats and “O” rings or needing to screw around with internal springs, levers, needles and things,. After 24 +/- hours of soaking with hand manipulated rinse through of the mixture I've found real good results. Been using one 4bbl Rochester for many years since that method of cleaning... with no problems. It had been well gunked and varnished after sitting for several years prior. On a 1990 “Malibu Skier” 20’ ski boat I’m restoring w/ a 620 hr 270 hp 350 cid, I plan to do same with its 4bbl that has set on engine unused for nine (9) years. I’ll also lube engine’s internals with special mixtures of Miracle Oil, kerosene, WD-40, Liquid Wrench and a pinch of pure rubbing alcohol poured over the valves and rockers as well as inside each cylinder. Let set for a week, then hand crank her over and over. Then drain oil pan and refill with new oil. Put a little new oil over valves and rockers and a pinch into cylinders and then turn her over many times with starter. Then put plugs back in (leaving ignition off-hooked) and turn her over till oil pressure is reached at least three or more times. Then hook up ignition and gas line, give her a whiff of starter fluid... and fire her off! Let’s Go Sking! I’m rebuilding this baby boat with my 12 yr old grandson!! Of course... He gets first dives at launch! See picts.