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

[Cheechako]

Originally Posted by 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

Nice to see the numbers. Not sure where you're getting your propane though. Currently $2.09 a gallon up here... I'm starting to like the Propane OB idea though, assuming they come up with tanks in a rectangular cage so they are not rolling around! The real down side is getting to the propane refill source. In many places they seem to be miles away from the water! With gasoline you can likely fill the tank from a fuel dock.

[osirissail]

Originally Posted by Cheechako

Nice to see the numbers. Not sure where you're getting your propane though. Currently $2.09 a gallon up here. . . .

I called up the local propane dealers here in and around Cocoa, Florida and that was the price they quoted over the telephone. Looking up the "average USA price for propane" you get the figure $1.25 for wholesale and $2.87 for retail.
Cost of Propane | National Propane Prices

Like anything else, if there is a "demand" at local marinas, etc. for propane they will start handing it. Especially since it seems to have a serious profit margin as compared to gasoline.

But Propane is and was available most everywhere in the US east coast, Bahamas and down island in the Caribbean. In the islands the locals use it for cooking and heating their house water. You would have to get some transportation to get to an "Ace Hardware" or "RV" store and other places who all sell and refill your cylinder.

Since we boaters normally have propane cooking stoves on board, there is already access to refills most everywhere cruisers stop. So getting refills is not a problem anymore than refilling our cooking stove/oven propane bottles.

Rigging a hold down system for a bottle in your dinghy is also not a major problem. What I see is a resistance to "changing" over to propane, I suspect we are used to dealing with gasoline tanks in the dinghy and resist doing something "different." There are a dozen different shapes and sizes of propane tanks in the "Defender" marine parts supply catalog so finding one to fit your dinghy should not be much trouble,
Cylinders/Tanks

[Ironhorse74]

This thread got me thinking. How about converting an existing outboard? First off it would have to be a four cycle or a two cycle with oil injection. With the "C" style kit you could leave the gasoline side intact. This would make the motor even more versatile. May have to find a cheap used outboard and give it a shot.

Simple Explanation

[deckofficer]

Originally Posted by Factor

On a more serious note I am really looking forward to battery technology getting ever more mature - one day I look forward to a electric dinghy motor that weighs (including batteries) the same as my petrol one, gives similar performance and has the same range from the motor with a 10 litre tank. I imagine that it wont be too many years, its just not yet.

Might be sooner than we thought. I had grown accustomed to the 5% per year of increased energy density of batteries, looks like a 300% increase for hopefully next year.
Envia Systems | Powering the next generation of electric vehicles

What is encouraging to me is this R&D company is based in California and has a manufacturing facility in China unlike Esstor, the so-called great hope from Texas. Esstor, IMHO, is just a shell company for big oil, intending to slow venture capitol from the real R&D battery firms.
http://en.wikipedia.org/wiki/EEStor

[capn_billl]

I personally like the idea of being able to plug in the BBQ tank to take the dinghy for a spin, I'm unlikely to try to run the BBQ off of unleaded

Having 1 fuel to keep on hand, and in a small lightweight compact container that basically just plugs in, is great. It also runs my torch, lights, and space heater, ....

[stevensuf]

osirissail i think your comparison with a 2stroke tohatsu is unfair, id imagine the propane powered units are 4 stroke or where does the lubrication come from?

You'll find the 5hp four stroke tohatsu consumes 1.7l per hour at wot versus 2.5l for the four stroke! Now using these numbers, I think youll find the four stroke hammers the propane!

[deckofficer]

I also prefer a single fuel, diesel, because it can come from renewable sources. As to how I want to use the energy from the diesel, nothing but electrons for all end use. Electric galley all the way down to the 1500 watt BBQ on the railing, electric propulsion for both the boat and dinghy. No propane or gasoline, and since we can not make our own fossil fuel, it is nice to know we can roll our own electricity.

[s/vfootloose]

I don't know about everywhere else but it seems in the states(S. Fl. at least) every 7/11, Walgreens, Home Depot, minimart has a swapout for propane tanks for about 20 bucks.

[Cheechako]

I like the idea. However, I usually filled my boat propane maybe every 5-6 weeks. Other than in the US it most often involved a cab ride etc. In fact, right in Ft Pierce Fl it cost me $18 cab rides plus the cost to fill.
For a dingy I might have to make the trip every week.... How about a pontoon dingy with each pontoon a propane cylinder? Ha ha...

[sailorboy1]

Originally Posted by Cheechako

.... How about a pontoon dingy with each pontoon a propane cylinder? Ha ha...

Sure, but how are you going to get that into town to refill?

[Cheechako]

fill it once for a world cruise.... Also handy for pirates...boom!.

[44'cruisingcat]

Originally Posted by Lagoon4us

Just cannot see anyone spending the bucks developing an outboard solely to run on gas.
More so an aftermarket conversion kit would be more likely.

As i said before, here in Australia we have run our cars on gas using aftermarket kits for 30+ years, not sure any car manufacturer has jigged their assembly lines to cater for the market.

Ford Aus is manufacturing Falcons which run solely on liquid injected propane. They actually perfom slightly better than the petrol ones. Holden is soon to follow I believe.

[Lagoon4us]

Originally Posted by 44'cruisingcat

Ford Aus is manufacturing Falcons which run solely on liquid injected propane. They actually perfom slightly better than the petrol ones. Holden is soon to follow I believe.

And that supports my comment, the manufacturers have taken this long in Aust to manufacture from the beginning.

As i said conversion kits would be most likely the go and IRONHORSE is onto it!!!

Cheers and thanks.

[44'cruisingcat]

Well no, dedicated LPG Falcons have been available from Ford dealers for decades, but they always had less power and economy than the petrol ones. Injecting liquid phase LPG is fairly new, and eliminates the power drop.

You still get less kilometers per litre compared to petrol though, due to the lower energy dnsity.

[HopCar]

Ironhorse, that in home Natural Gas compressor is pretty neat. I wish I had natural gas available in my neighborhood. I'd use it to heat water and run an emergency generator. I'd cook with it but my wife won't let me have a gas stove. Don't get me started on that fight!

I'm still having a hard time getting propane outboards. Lehr really jumped the gun in showing them at the Miami boat show. I've got customers waiting for them and I want one.