Is This True

[matt76]

The Briggs and Straatton 3hp 48v motor says it produces 150lbs of thrust:
http://www.smalloutboards.com/bg3.htm

Does this mean that the minn kota MK202/EM with 36v 202lbs of thrust could be compared to 4hp?
http://www.minnkotamotors.com/produc...ail.asp?pg=fem

something tells me no?

[ted655]

Is there a scale or formula that equates #s of thrust to HP? If so, then I guess you can metreculate.
But if it is possible to create thrust through gear ratios, then it becomes a marketing game.
Better way to compare would be a SAE ratingm To me, I would want to know the discharge rate, speed @ ? RPM and "perfomance data.

[Guest625101138]

Thrust does not mean much unless you want a tug boat. Thrust gets down to grip in the water not so much HP. Big diameter prop will give better grip and more thrust for the HP if it is pitched right.

To get the best from the HP you need to match the prop to the application.

Rick W.

[jehardiman]

They are talking bollard conditions here and there is a lot of hype and a little smoke and mirrors.

A B-series propeller produces ~35 lbs of thrust per shp at bollard wether it is 3" in diameter or 25'

A Kaplan prop in a well designed nozzle produces ~40-50 lbs of thrust per shp at bollard depending on tip conditions. I have designed a Kaplan that has produced 65 lbs of thrust per shp in at bollard. But better results are acchieved with open water props.

I have also designed a set of counter-rotating props that achieved 215 lbs of thrust with 0.75 shp in. It's just a game you can play depending on how you set up your design conditions.

Like Rick said, the more important point is designing for your operating point, not some numbers game for ads.