T-Pain Is On A Boat: Re: [Electric Boats] Re: Hello Everybody!

Tuesday, July 19, 2011

Re: [Electric Boats] Re: Hello Everybody!

Hi Eric,

Quick one... you say 1kW per ton? I assume you're not referring to metric tonnes, so can you tell me in lbs or kgs what a ton in the US is?

My boat will displace around 3,300 lbs. Would the 4kW I was anticipating would be overkill?

Thanks,

Mike

On 19 Jul 2011, at 15:24, Eric wrote:

Hi tntcontrol,

Welcome to the group! You've got 2 steps to an electric repower project. You need to determine the size of your electric drive and once you have an idea of what your "watts to knots" ratios might be, then you can size your battery bank to deliver whatever range that you desire (within reason)

I've finished the conversion of my 1964 Cheoy Lee Bermuda 30 ketch with a 5.5kW electric drive from Propulsion Marine in Santa Barbara. I also chose to install an 8kWh (160Ah @ 50V) Lithium battery pack that gives me an electric only range (to 80% depth of discharge) of a little more than 20nm at a little more than 4kts.

I suggest that you contact all of the regular vendors here, AMeP, ASMO, Electric Yacht and Propulsion Marine and see how you feel about their offerings. Because they are vendors, you should watch thier "spec-manship". Make sure that they qualify performance numbers, for example, quoting a range that goes to 100 depth of discharge isn't entirely practical, you would have no reserve and running any battery down that far isn't good for it. But that number might still be useful for comparisons.

The good news is that your boat falls into the "sweet spot" for the electric conversion of auxiliary sailboats. At a displacement of 10,000 pounds, your boat should have a drive with at least a 5kW continuous power rating. The rule of thumb here is 1kW per ton of displacement. My Bermuda 30 has a displacement of 10,200 lbs, so our boats should be pretty close in power requirements.

If you have time to come up to Marina del Rey some weekend, I can show you my boat and give you an idea of how yours might turn out.

Fair winds,
Eric
Marina del Rey, CA

--- In electricboats@yahoogroups.com, tntcontrol <no_reply@...> wrote:
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> Awesome to find this group! i own a '66 islander '33 that i am wanting to convert to a e-boat. i am starting my research and am interested in finding a electric drive that could get my boat from Long Beach to Catalina (26 miles or so) on a no wind day. Also i am replacing my gas Atomic 4..... I will be stoked to get rid of that.... Any suggestions are appreciated. Thanks you!
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