Propane Outboards

[Rich Young]

Cruising World has an item on a new line of propane-fueled outboards.  Available in 2.5 and 5.0 HP models; only the 5HP model is available in a sailboat-friendly long shaft.  The article indicates that the energy in a 20-pound propane tank is about equivalent to 5 gallons of gasoline.

Besides cleaner emissions, I see a couple advantages to this fuel. 

1. Fewer systems on the boat - you could use a single tank system for both cooking and propulsion
2. No liquid fuel spills in the water when refilling, disconnecting for storage, etc. That means cleaner marinas & harbors, healthier marine life
3. Cheaper to operate
4. Refueling is faster than charging the batteries for an electric outboard
5. Lighter - if gas is 6lbs/gallon, 20lbs of propane provides the energy of 30lbs of gas.  So significantly easier to lug around.  Also lighter in the boat than a battery-based electric system

And disadvantages:

1. Propane may be harder to find than gas or diesel out there in the wider world
2. If you're using disposable mini cannisters, you lose some of the "green" benefit
3. Not mid-ocean refillable like an electric outboard is
4. Propane leaks are dangerous (because it's invisible and heavier-than-air) unless the tanks vent over the side

Am I missing anything?  Do others feel like this is a neat new product, or just hype?

[Galway Bay]

I checked out the link - this looks really good. I used propane powered 12hp generator at work for years it was top class. Also I ran a Renault 18 station-wagon [pick-up]for several  high-milage years maybe the best thing I ever drove...

[Rich Young]

Yeah, the "20lb propane ~= 5 gal gas" figure was kind of offhand in the article and I didn't know how accurate it was. It seemed surprising  - if it really offers that much better energy density, why would we be "discovering" propane so late?