A: A CRF GPH rating is a prediction of how fast a boat should sail around a 1 mile course whose content consists of 1/3 VMG upwind, 1/3 VMG downwind, and 1/3 reaching, in a wind range of 8-12 kts.  This suggests that a boat with a CRF GPH handicap of 600sec/mi should get around a 10nm course (whose content and weather conditions are near the rule targets) in 600sec/mi*10nm=6000sec, or 6000/60=100min, or 1 hr 40 min.  This prediction can be a huge help to race organizers and officers in deciding on appropriate class breaks and course lengths.  For the sailor, it can be helpful in estimating when his boat may finish a race, and thus when the crew should get home for dinner (or to the bar).  The CRF GPH can also be very useful in post-race analysis, by dividing a boat’s elapsed time for a race by the course length, and comparing that to the boat’s CRF GPH.  If a boat sails a course slower than her rating, (eg the boat with the CRF GPH of 600 actually took 1hr 41 min 17 sec to sail that 10 mile race, so she did it in 1*3600+41*60+17=6077sec, or 607.7 sec/mi), the wind might have been light, the current adverse, or the boat had two bad tacks, or some combination thereof.  If, on the other hand, the boat sailed the course faster than her rating, there likely was a lot of breeze, and/or the course content included a lot of reaching.  (NB that in CYOA Technical Committee uses this same comparison between rated and ‘as sailed’performance every year in its analysis of how well CRF predictions match up with on the water realty over a full season of racing).