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post #1 of Old 02-24-2010 Thread Starter
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Announcing the Lean Green Machine Challenge

Here's the throw-down on this hoe-down:

Build an electric propulsion system that works as well as, if not better, than my diesel engine.

Here's the low-down:

I have an aging Yanmar 1GM-10 engine powering my Georgian 23. I have a 10 gallon fuel tank. My engine puts out a raging 9 hp and 13 ft/lbs of torque. It burns 1/3 gallon/hour at cruise (3000 rpm) At that engine speed, it pushes my boat comfortably at hull speed (5.5 knots, roughly). Based on the numbers, under power I have a 30 hour range. Total weight of the propulsion package including full fuel tank is under 320 lbs. it also has an alternator which handles charging my starting battery and house battery. My slip is on an unserviced dock which means that shorepower charging is not an option so we are already running pretty lean and mean with our electrical usage. I don't have much room for a big solar array, although I am installing 30 watts worth of panels on my new davits. because this is a small cruiser, there is not a lot of spare space aboard, so it's nice to have a compact propulsion system that hides under the cockpit sole.

Sadly, I need to freshen my engine this year. Compression is getting lowish, so I see new rings and a freshened head in my future. Likely gonna cost me about $1000 and a weekend of my time (I do my own wrenching.) I am contemplating whether it makes more sense to pull the engine out and install a new one, which would be in the $5k range.

So, the discussion about electric propulsion got me thinking...

If a new engine would set me back $5k, then:

**I will offer $1000 to anyone who can build and demonstrate a reliable system that will do what my Yanmar does for the same money, weight and space. Furthermore I will BUY the system that meets the parameters outlined below:**

30 hour range at hull speed*. (*New! Revised! Proof that I really really want somebody to succeeed! The range requirement is now 50% LOWER!!!!!!!! 15, FIFTEEN, ONE FIVE hours!!)
Charging onboard electrical systems.
Total weight under 320 lbs.
Must fit under cockpit. 74" long x 24" wide x 20" high.
Total cost under $5000.

This is a small cruiser, 20' at waterline, displacing 4350 lbs.

So all of you inventors, dreamers, clean/green propulsion proponents, this is your change to convert me, and earn some cold hard cash at the same time.

Last edited by bljones; 02-24-2010 at 10:04 AM.
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