T-Pain Is On A Boat: Re: [Electric Boats] electric drive for a pram tender

Saturday, September 5, 2009

Re: [Electric Boats] electric drive for a pram tender

Rob,

I have a Torqeedo 801 and it is almost as powerful driving my dinghy at full throttle as my 2hp 2-stroke outboard. Unfortunately, full throttle will drain the battery completely in about 20 minutes. To get 1 hour or operation, the motor needs to be run at half throttle or less. This equates to about 3kts in an inflatable, in still water, no headwind.

I use this motor on my inflatable with my F-27 trimaran at the isthmus at Catalina Island and I try to anchor as close to the dock as possible. At a couple of hundred yards, I can get 4-5 round trips in a protected anchorage over the course of a weekend, though I run slow whenever possible. I also carry the small wall charger that comes with the motor and plug in any where I can while I'm ashore.

Realistically, a 2hp ICE outboard will cost less than 1/2 the price of a Torqeedo, and run over 3 hours at full throttle on 1 gallon of gas. With a gas engine, you won't have to worry about range or power.

I bought the Torqeedo to be able to carry the motor folded in one of my float compartments. Now that I own it, I have accepted the considerable limitations of the system and have adjusted my usage to match the motor. It is the most efficient answer available today in electric motors considering total operating size and weight, but the cost is prohibitive. Normal trolling motors with just one L/A battery are cheaper, but will weigh 3-4 times the Torqeedo or an ICE equivalent.

Given your description of your situation, I would probably choose the Yamaha. I'm a big fan of electric, but trying to use electric under difficult conditions will be an expensive experiment that could end up very dissatisfying.

Good luck,
Eric
Marina del Rey, CA

--- In electricboats@yahoogroups.com, Rob Johnson <dopeydriver@...> wrote:
>
> I've checked out the torqeedo site , they look pretty good.
> I have a mate whose boat isn't as far out as mine , and who is a very strong rower , and he has been stuck on his boat for half the day , waiting for the wind to die down enough to row ashore .
> How would the torqeedo handle those sort of conditions ?.
> Regards Rob J.
>
> --- On Sat, 5/9/09, dennis wolfe <dwolfe@...> wrote:
>
> ----- Original Message -----
> From: dopeydriver
> To: electricboats@yahoogroups.com
> Sent: Friday, September 04, 2009 5:53 PM
> Subject: [Electric Boats] electric drive for a pram tender
>
>
> I have a little 6ft 6 inch tender that I need to motorize.
> I've checked my options , it seems it gets down to a 2 hp 9.8 kg Yamaha..
> I checked out a Minn Kota , but the battery weight was just prohibitive .
> Its use will be to get me and/or passengers and gear out to my yacht on a swing mooring , often working in to strong headwinds.
> I spoke to the appropriate salesman in a very reputable company , and he explained that the problem lies when I need to do more than one trip , out and back.
> And then on return , out and back.
> The Yamaha could do it on its little tank full , or a spare litre of juice , but the Minn Kota ?.
> I haven't made any decisions yet . I'd prefer not to go to an IC engine , but I can't see how I can get around it , without going to a very expensive battery.
> And when I do get to go sailing , I'll not be leaving the engine on the tender , it will have to come on board the yacht.
> Any practical suggestions ?.
> I'm in Sth Australia.
> Rob J.