Forget Electric or Junk Gasoline - Here Is The Way . . .

[mbianka]

Originally Posted by Don Lucas

hell my Honda 2HP dies more than it runs!

Don:

That's unusual for a Honda product from my experience.

[BuckeyeTom]

Originally Posted by Cheechako

on propane the engine should last forever. Carring a propane cyl around in the dingy doesnt sound like fun though... and propane is usually alot more work to get filled than getting gasoline. When I was just out of high school i worked as a mechanic for a time. The local cabs used propane. The conversions were really simple. Those engines were clean as a pin inside even after 100k miles. Bright shiny silver heads and piston tops...

It would occurred to me that propane is not as good a lubricant is using either gasoline or diesel doesn't be lubricated parts walls and rings become more worn when using propane

[HopCar]

Buckeye Tom, Lubrication doesn't seem to be an issue. There are plenty of fork lifts and taxi cabs that run day after day on propane. Time will tell with the outboards.

[Sailmonkey]

Gas isn't a lubricant either, that's why 2 strokes need oil mixed in

[svBeBe]

And, you can get your propane engine repaired where?

Get 15hp gasoline outboard and a dinghy that will handle 15hp so that you will be able to use the little boat to move the big boat or carry 4 adults with dive gear. Anything smaller is a toy.

If you plan to sail anywhere other than marina to marina, be sure to try and equip with common stuff. If you equip with weird stuff, you will be very sorry.

Bill

[Sailmonkey]

Originally Posted by svBeBe

And, you can get your propane engine repaired where?

Get 15hp gasoline outboard and a dinghy that will handle 15hp so that you will be able to use the little boat to move the big boat or carry 4 adults with dive gear. Anything smaller is a toy.

If you plan to sail anywhere other than marina to marina, be sure to try and equip with common stuff. If you equip with weird stuff, you will be very sorry.

Bill

Propane engines are no different than any other engine, the carb is the only thing that has changed.

I don't consider our 2.6m dinghy a toy, and I have no desire to flop a 15 up onto the rail of our 32' boat. Our 5hp mariner has been one of the least problematic things we have. Size is relative, our outboard has in fact moved the mothership about 15 miles down the ICW following an exhaust failure of the main engine, not to mention other standard dinghy duties throughout mexico, belize and guatemala.

[HopCar]

A service network is being set up using existing outboard shops. The engines really are just like gasoline engines except for the propane carb thingie. Sorry I don't know what they call it, but it isn't a repairable part anyway. If it goes bad you just plug in a new one. Any mechanic that works on modern outboards will be comfortable working on these.

[osirissail]

I do all my own repairs be it the diesel engine or my outboards. The economy of using a 5hp outboard versus a 15hp is significant since I have both on board and have used both for a decade. Since these new "propane" outboard engines are basically only modified gasoline engines, parts for anything other than the propane carburetor should not be a problem.

So I was thinking about the Propane Outboards for possibly fuel savings as compared to gasoline of the same size engine. But from my calculations below there seems to be less than 10% difference between the cost of fuel used between the two types. IMHO, not significant unless the repair and maintenance costs are significantly different - which we won't know until the Lehr engines have been in use for a number of years.

Current propane cost $4.39/gallon
5 gallons Propane = $21.95
Propane is 4.2 lb./gal = 21 lb.
Propane = 92,000 BTU/gal. 5 gallons = 460000 BTU
1 hp = 10,000 BTU/hr 5hp needs 50,000 BTU/hr

460,000 / 50,000 = 9.2 hours on 5 gallons of Propane

$21.95 / 9.2 hours = $2.386 / hour to run Propane

Current gasoline cost $3.73/gallon
5 gallons Gasoline = $18.65
Tohatsu 5hp outboard burns about 0.7 gallons/hour

5 gallons / 0.7 gal/hr = 7.143 hours.on 5 gallons of gasoline

$18.65 / 7.143 = $2.611 / hour to run gasoline

Gasoline 5hp Outboard $2.611 /hour
Propane 5hp Outboard $2.386 /hour

Propane is about $0.225 per hour cheaper.
Or, 8.6% cheaper to run (fuel only)

Sources for calculations:
Fuel Consumption
Tohatsu Outboards - Fuel Consumption Chart

[sailorboy1]

Yes, but to me the attraction is not really cost, it's dependability (but less cost is always better). Since I don't use my gas outboard all that much the gas is the biggest problem, along with the spark pug problems caused by the gas.

So since the propane solves this is is looking like a winner to me! And now you tell me it will cost less to run.

[haaho]

Originally Posted by 44'cruisingcat

Propane will form an explosive fuel/air cloud far more readily than petrol will.

I think it is just the opposite.

[Kettlewell]

The one big downside I see for the long-term cruiser is the need to cart around the heavy propane tanks. In my experience it is very rare to find propane at a marine fuel dock, or within reasonable walking distance to the water. I have carefully noted where I can get propane for my cooking stove along the East Coast and I carry enough for a minimum of 3 months between fill ups. If I was using the propane outboard every day like I would when cruising I would need to fill tanks much more often, which would be problematic without a car, etc. However, if I was just in my home waters, had access to a car, and knew exactly where to go for propane it would seem to be pretty convenient. There would be no worries about the dinghy filling with water in a heavy rain and polluting your gas tank, if the engine runs cleaner it is good for the environment and probably means less engine maintenance too, and propane is reasonably cheap. No more worries about phase separation with ethanol fuel either.

By the way, a full five-gallon gasoline tank weighs in the vicinity of around 34 pounds and a full five-gallon steel propane tank is around 40 pounds, so the difference is not all that extreme.

[Kettlewell]

Just for kicks I called up my friendly neighborhood hardware store and they charge $19 (including tax) to fill a 20 lb. propane tank, which should be about 5 gallons. Regular gasoline at the pump is around $3.97 per gallon around here, making the relative cost per gallon very similar. Two other advantages I forgot about are there is no need for adding 2-stroke oil (if you have a 2-stroke outboard) and no issues with the fuel going stale over the winter. I don't think propane ever goes bad.

This article discusses the relative efficiency of propane vs. gasoline vs. natural gas and concludes that a propane generator would burn 1.36 times as much as a gasoline one, so to equal the efficiency of 5 gallons of gasoline I would need about 6.8 gallons of propane. At today's prices around here that would mean $25.84 in propane to equal $19.85 worth of gasoline. However, to that gasoline I would be adding some rather expensive 2-stroke oil and some StaBil to keep the mess from going bad, so the difference in cost would be less than at first blush.

[deckofficer]

I don't want to burst your bubble, but you can't add oil to propane, so both the 2.5 and 5 hp models are 4 stroke. If you run propane on a 2 stroke it would last a couple of minutes before becoming a paperweight without oil in the intake mixture.

[Kettlewell]

Nobody's talking about adding oil to propane. Just pointing out that you have to add that into your cost calculation when comparing a 2-stroke outboard to a propane-powered one.

[deckofficer]

Whoops, didn't read too closely did I? me bad.