A question about horsepower

Using the Bandit as a benchmark with a quoted horsepower somewhere between 100 and 120 (correct me if I am mistaken)

I've just been looking at jetskies and have seen several specs quoting 165HP up to 300HP with engines around 1200cc-1300cc

I'm guessing that the Bandit horsepower is measured at the back wheel where the jetski somewhere on the engine drive.

Is this trick advertising or are there several ways to state horsepower from an engine.

there are a couple of ways to calculate hp but they produce similar results.

Bandit hp as shown in your manual will be measured at the flywheel. knock about 15-20% off for driveline losses and you'll get a ballpark rear wheel hp figure. The Bandit is more about torque than hp.

Watercraft donks don't need a lot of torque they rely or RPM to drive the jet/prop. Engines with high rpm have the potential to generate higher hp (eg an F1 car 2.4 litre V8 revs to 19 grand and makes 850hp). My mates ski boat has a 1.5 litre supercharged unit rated at 400hp so your jetski figures seem about right to me.

A couple of years ago I had a look at at couple of jetski's at the Sydney boatshow. From memory one of the Yamaha's was using a supercharged R1 motor and the Kawasaki a supercharged ZZ1400 engine, pulling something like 250 HP! 1250 bandits generally pump 100 - 105 BHP rear wheel on a dyno, (I think this is what Dale quotes on Holeshot). Horsepower is the product of force and distance over time. That's why its dimentions are ft-lbs per second (i.e. 1 hp = 550 ft lbs per second).