T-Pain Is On A Boat: Re: [Electric Boats] 3201 BROWNING GEARBOX

Tuesday, September 20, 2011

Re: [Electric Boats] 3201 BROWNING GEARBOX

James

I take it that you are a distributer. I kind of remember talking with you several years ago about your systems.

From: James Lambden <james@toolboat.com>
To: electricboats@yahoogroups.com
Sent: Tuesday, September 20, 2011 2:43 PM
Subject: Re: [Electric Boats] 3201 BROWNING GEARBOX

Aaron,

Be careful that your pitch and gear ratio will give you the desired top end speed. Going upwards of 3:1 without enough pitch might not give enough top speed.

When choosing a very high reduction gear ratio, to get a high enough pitch requires a larger propeller which can get very expensive quickly.

Do you need a supplier for the gearbox?

James

Propulsion Marine

http://www.propulsionmarine.com

On Sep 20, 2011, at 3:17 PM, Eric wrote:

Hi Aaron,

For a 10kW system, a 3301 seems like the right selection from the Browning Helical gearbox line.

Since you're building the boat from scratch, you might be able to work in a larger prop. It would take a bigger reduction ratio, but it should be more efficient (on the general theory that larger slower props are more efficient). Browning has gear ratios past 5:1 for their gear boxes.

I had to enlarge my aperture just to fit my 13 x 15.5 prop as part of my conversion. Given that maximum prop size, the ratio that James selected of 2.55:1 seems to strike an effective balance between power and speed across my normal operating range.

Eric

--- In electricboats@yahoogroups.com, Aaron <akenai@...> wrote:
>
> I am back looking at installing an electric motor in the 36' steel sailboat I am building. 31' LWL, 10'6" Beam, 10 ton disp. I have a used Westerbeke 44B 40hp diesel but would rather not use it.
> EBay has a 3201 gearbox but I was thinking it was too small.
>
> From: James Lambden <james@...>
> To: electricboats@yahoogroups.com
> Sent: Tuesday, September 20, 2011 10:25 AM
> Subject: Re: [Electric Boats] 3201 BROWNING GEARBOX
>
>
> Aaron,
>
> The limitation is most often the continuous thrust rating of the bearing at the back of the motor, though torque and input rpm are issues too.
>
> The 3301 is rated at 550 lbs of continuous thrust and the 3401 is rated at over 1,000.
>
> The larger gearboxes can't spin as fast as the smaller gearboxes.
>
> What is the torque of the motor, and the rpm where you are producing that much power?
>
> We don't exceed 2,000 input rpm with the gearboxes we use on our units, and most often set the drive up at 1900 rpm.
>
> James
>
>
> http://www.propulsionmarine.com