Friday, March 26, 2010

[Electric Boats] Re: Torqeedo speed prop

 


Greeting everyone, I have been following along for quite some time. I am a small wooden boat builder and I have had interests in electric power since 1995. I am converting 2 boats (both personal boats at the moment) to electric power. One is a 38 foot sailboat, the other is a 16 foot sailboat. I am an innovator, designer, fabricator, inventor and I prefer using bits and pieces to get to the end product rather than buying off the shelf for self-rewarding reasons, not to mention financial considerations.

In the near future I will be posting my procedures and methods. Maybe my idea will work and maybe it won't or perhaps just not efficient enough, but the challenge is just as rewarding as the success rate. However something Capt. Todd said about the old school trolling motors not having enough power, but being quieter since they are submerged, got me to thinking.

Minn Kota has a model called "salt water engine mount". Which I might consider using, if my home made plan fails. http://www.minnkotamotors.com/products/trolling_motors/engine_mount/saltwater.aspx Seems they are dual motors that mount on the cavitation plate of an outboard. On their model page it states they have a 160lb thrust model RT160EM, but on the "full story page" it mentions there is a RT202EM model.

I have experienced the Minn Kota 55 and found that it moves a 14 foot dinghy style boat along quite well. It appears that the RT160EM model is about 3 times the power, so would these dual motors not have sufficient power for the style and size of sailboats commonly mentions on this forums postings? It would seem that all is required is to fabricate a plate for them to attach to and then mount that plate to the hull, after removing the existing prop shaft. Then all you would have is the wiring coming up the transom.

By the way I am assuming that the combined lb thrust of the 2 motors equals 160 and 202 lbs thrust for the biggest model.
Thanks for your thoughts and ideas
Peter

--- In electricboats@yahoogroups.com, "epowermarine" <todd@...> wrote:
>
> FWIW, here are my comments on the recent `Torqeedo noise'; complaint. Disclaimer, I do sell Torqeedo's (and Parsun, Ray, DualPro, ElectraCraft, and others certainly) but I also USE all of these products which (for these purposes) is perhaps much more important than selling them.
>
> Anyway, The original Torqeedo planetary gears did make some noise. Those are the TRAVEL 401/801 and Old Cruise 2.0 Tiller models. Many changes have been made, and the new Travel 1003/503, Cruise 2.0/4.0Remote and 2.0 Tiller have much, much quieter gears. It's the incremental improvements being added to the entire lineup and it really is a big change. If you have heard an `old' motor you really need to hear a `new' one to appreciate the difference. My assessment is that the noise is not objectionable, by my terms nor any of my passengers.
>
> Brushed air-cooled motors make their own unique noise, as do brushless DC, belt drives, gear drives, and chain drives. As previously said by another poster the only thing truly silent motor is the submerged old-school trolling motors; but they don't have enough power to do what most of us need to do. Anything spinning pretty much makes some kind of noise.
>
> BTW: If anyone happens to be in the West Palm Beach FL area please do come by the boat show and say hello! I'll be there thru Sunday.
> Capt. Todd
> www.epowermarine.com
>
>
> --- In electricboats@yahoogroups.com, "dennis wolfe" <dwolfe@> wrote:
> >
> > My $0.02 on noise: Anything moving makes noise, spinning things make noise, especially if they are a little bit out of balance (i.e. real world spinning things). Prop blades create a pressure wave that can make a little vibration in the hull as the tip goes past. The brushes scraping over the commutator gaps makes noise in a DC motor. Gears especially make noise. Lets keep electric drive noise in perspective - exploding fuel REALLY makes a lot of noise.
> >
> > The smaller Torqeedo's have a double planetary transmission needed to reduce the high speed of a small brushless outrunner motor low enough to drive a big efficient prop. (that's the secret of their high efficiency). You can hear the gear whine on youTube videos. I understand the new larger 2.0 and 4.0 models are significantly quieter but have not heard one run myself. Maybe Cap'n Todd has a comment?
> >
> > The quietest drive I know of is an old fashioned trolling motor. All the moving parts are under water, the motor is small and there are no gears as they are direct drive.
> >
> > Denny
> >
> >
> >
>

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