Boat Horsepower Claims Over The Years

[MonacoMike]

I have heard from multiple sources that various manufacturers have used different measures for horsepower over the years. The most common story is that at one point most manufacturers measured horsepower at the prop, then some started measuring it at the crank so they could advertise a higher horsepower number (or the same horsepower cheaper), and later most all manufacturers measured it at the crank which is todays standard.

So my 1985 Monaco is marked a 260 hp. I was told that was a prop hp for that era and if measured at the crank it would be near 300 hp. Any truth to that? My 85 will out-plane and outrun many advertised 260 hp vessels in a race. I get that there may be other differences.

MM

 

[FootballFan]

Curious topic, one I have wondered about.

Way long ago, when I was a small tyke, I remember our ski boat which had a 40hp evinrude. Would pull 2 slalom skiers.

And I mean jerk them out of the water, not drag them forever.

Are there many 40hp motors today hat would do that?

 

[MonacoMike]

The standards for many things have been far less than "standards" for years.

MM

 

[Lazy Daze]

Actually, it's the other way around. It used to be measured at the crank. Somewhere in the mid-90's the transition to advertising prop-shaft HP happened. I can only speak about Merc, though. But it is still prop-shaft HP that is advertised.

Why can you beat other boats? WAY too many variables. Anything from hull design to weight to style of boat and even the way the operator runs/trims the boat. And probably more variables, still.

2-strokes are screamers, for sure. They do make their power very quickly (rev up fast) since they make power (internal explosion) every time the piston moves up, as opposed to every other time... "2" strokes (up/down) as opposed to "4" strokes (up/down/up/down). And who knows - maybe the manufacturer's weren't quite as accurate in their HP-measuring ability a long time ago.

 

[MonacoMike]

Actually, it's the other way around. It used to be measured at the crank. Somewhere in the mid-90's the transition to advertising prop-shaft HP happened. I can only speak about Merc, though. But it is still prop-shaft HP that is advertised.

Why can you beat other boats? WAY too many variables. Anything from hull design to weight to style of boat and even the way the operator runs/trims the boat. And probably more variables, still.

2-strokes are screamers, for sure. They do make their power very quickly (rev up fast) since they make power (internal explosion) every time the piston moves up, as opposed to every other time... "2" strokes (up/down) as opposed to "4" strokes (up/down/up/down). And who knows - maybe the manufacturer's weren't quite as accurate in their HP-measuring ability a long time ago.

Dennis where do you think my HP number came from on the SR 1985, crank or prop?

MM