T-Pain Is On A Boat: Re: [Electric Boats] Electric set-up for cruiser

Thursday, December 9, 2010

Re: [Electric Boats] Electric set-up for cruiser

Denny:

Thanks Denny, I actually got alot of info off of your article in WB magazine. Sorry I forgot to mention that in my initial post.

I used the dimensions from your boat to come up with a beam to length ratio slightly higher than yours. WL is just under 33'.

Building is some time off as I have to finish building my house first.

Also thanks for the wooden boat design forum suggestion; I will post there to see what people think of the hull design etc.

Cheers!

Shawn

On Wed, Dec 8, 2010 at 9:10 PM, dennis wolfe <dwolfe@dropsheet.com> wrote:

Hi Shawn and welcome to the group. You are starting off the right way, with a boat designed to cruise efficiently at displacement speeds.

You didn't state the wl length but guessing 30' I ran a few numbers for a 7,000 # weight hull with a 300ah 48v battery bank. At 85% electrical efficiency and 80% depth of discharge you would get:

4 mph 7.9 hrs 1.3 kw 1.7 hp

5 mph 3.7 hrs 2.5 kw 3.4 hp

6 mph 2.0 hrs 4.3 kw 5.8 hp

Your 20 - 30 mile range at 4-5mph is doable with just the batteries.

I don't know much about solar cells but averaging 2kw, especially in your neighborhood, takes a lot of loonies, weight and area. Electric boats are dirt cheap to run if you can recharge from the grid, very expensive otherwise.

Best of luck with your project.

If you are building your boat out of wood, be sure to check out the Woodenboat forum. The folks there would love to follow your building progress.

Denny Wolfe

www.wolfEboats.com

----- Original Message -----

From: Shawn Gates

To: electricboats@yahoogroups.com

Sent: Wednesday, December 08, 2010 3:25 PM

Subject: [Electric Boats] Electric set-up for cruiser

Hello everyone:

This is my first post, so please forgive any mistakes, etc..

I have been reading some of the discussions going on and thought that I would join in, mostly to learn from your collective knowledge.

I am interested in an electric drive for a new displacement cruiser. I know that most of you are sailors and your electric systems are set up to act as an auxilliary (sp?). My boating area is system of lakes, rivers and canals that stretch from Lake Ontario (Kingston, Ontario) to the Ottawa River (Ottawa, Ontario) Either way I get to the St. Lawrence or the Great Lakes.

I am also very new to boat design but have put pen to paper ( or, mouse to autocad) to come up with a 33' double-ended cruiser that, given your experience with "slippery" displacement hulls designed for sail, I feel is worthy of consideration for electric power. I come to this conclusion after reading lots of books and articles (mostly, it seems by Dave Gerr) about hull shape and power requirements. I have also been inspired by a neighbour of mine who runs an old 30' Maine lobster boat converted to a hybrid system that has both an 8 hp DC motor and a 10 hp AC motor with a 10 kw diesel generator. His boat is as I said 30' and displaces about 16,000 lbs. Now, he only runs off batteries for a portion of his 4 hour cruise. (check out rideauboattours.com).

I plan on installing the 8kw dc motor that is offered by Thunderstruck along with the associated electric gear. I'm hoping that, like Mundoo III (See WB magazine for article), to eventually run this vessel in the 4-5 mph off of some solar panels, but initially using 8 AGM 6 volt batteries from Lifeline (either 300 ah @ 20hrs or 220 ah @ 20hrs rate). I think that a range of 20 to 30 miles is a reasonable expectation given the speed and hull shape. I can only swing a 16" prop. probably with at least a 2:1 gear reduction (toothed belt). The boat I estimate to displace approx. a little over 3 long tons (7,000 lbs) I've also estimated a DL ratio in the 120 region (quite light for it's length, but then I'm pretty well confining myself to lakes & rivers.

What do all of you think. I welcome any comments or advice. Thanks!

Shawn