b1 gear ratio
 

Question from a novice: A 1.5:1 ratio means that for every 1.5 revolutions of the engine, the prop turns 1? Is this correct? Also, what gear combinations are available for a B1? Thanks........Casey

Re: b1 gear ratio
 

Casey,
That is correct. Gear reduction also acts like a torque multiplier, which is good since we don't have multi speed transmissions like cars.
For most boats that run in the 70-100 MPH range, 1.50s are fine, as the propeller selection is broad (say from 24" to 34"). Over 100, most opt for 1:23/1.36 ratios, which allows the boat to run lower pitch propellers (than 36"+), and still maintain decent acelleration.
There is also a school of thought amoung propeller specialists that extremely high pitches (36"+) are not as efficient (more slip) as lower pitch props.
Regards,
Steve