Re: [Electric Boats] Re: Small leg question

Hi Gavin, sorry for napping...Club election stuff to chase. Anyway,
we generally don't think about reverse in our applications but we've
done a few like the electric kickers and patrol boats we've used when
testing on a couple electric only lakes, and for motor tests. One of
those can be seen in the photos section...it's the green aluminum
skiff on the trailer. The motor in that case was a cheap golf-cart
motor. That unit uses a Yamato racing gearcase, and reverse was
through a contactor. A note here: I've gone edited the e-racing album
to include photos of the current 48v runabout and 144v hydro record
holders and Fred's UIM world record certificate.

I recall seeing a comment about outboards slipping in the wrong
direction...Not sure what that meant but I'll guess he was speaking
of converted shifter units popping into neutral under load in
reverse. Generally the problem there is that conversions remove or
weaken the makers' detent/lockout devices. When reverse loading
forces the gearset to neutral there's little to nothing preventing
it. We generally locked the gears in place...sometimes, when an
opposite turning prop offered advantage, in reverse.

For the most part we ran non-reverse units. They were simpler,
weighed less and at least one (Yamato) used roostertail water thrown
from the prop for cooling and had no water pump. In those
applications where we needed reverse a contactor or a Rube Goldberg
Frankenstein-switch series worked fine. Reversing doesn't appear to
damage motors. It's only a short term low-RPM thing and shouldn't be
a problem.

Another thing worth looking at when picking a unit might be the way
shafts are supported. Racing and many commercial use units use
bearings, while family blasters and fishing motors tend to use
bushings. Bushings probably don't affect reliability much, but they
do add friction. The red motor on out 48v hydro in photos runs an OMC
25 hp commercial fishing unit with bearings. Another trick to
consider is fairing the unit with Bondo. You can make a unit much
slipperier by shaping, and it can be measured with an amp-meter
reading on tests between shaping sessions...We cut amp-draw by 50%
using this trick.

I'll shoot out a picture to you and to Jon n Wanda of a motor setup I
think might answer the original question. It's a 1hp Bosch PM on an
OMC 2hp leg we used on a foam sailboat. Too bad we can't attach pics
here.

John

On Oct 18, 2009, at 8:50 AM, Colin Girvan wrote:

> I thought I had read somewhere that there was a problem with using
> the electric motor for reverse. Has anybody been able to solve this
> as I am thinking of having the outboards controlled remotely and
> though more expensive using reversing contactors would be much
> simpler. The other advantage would be that shifting would be
> smoother and faster.
>
> A quick question for John Paramore if he's online lately, I thought
> the outboards they use for racing don't have a reversing gearbox so
> would these work running an electric motor backwards. If so are
> they readily available and what cost. I guess that's three questions.
>
> Thanks for any help.
>
> Colin Girvan
>
> BC Canada
>
> --- On Sun, 10/18/09, Myles Twete <matwete@comcast.net> wrote:
>
> From: Myles Twete <matwete@comcast.net>
> Subject: RE: [Electric Boats] Re: Small leg question
> To: electricboats@yahoogroups.com
> Received: Sunday, October 18, 2009, 4:34 AM
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>> Most outboard gearboxes slip in the wrong direction.
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> I knew there was a good reason why I used the mechanical direction
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> __________________________________________________________________
> Get the name you've always wanted @ymail.com or @rocketmail.com! Go
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