Not all sailboats sail the same speed in the same conditions. Differences in size, hull design, and equipment all influence the speed of a sailboat.
In order to eliminate these differences, several handicapping systems have been established. The one the Michigan City Cruiser Class (and many others) has chosen to adopt is PHRF.
For more information:
Basically, PHRFs represent the relative speed of a sailing vessel based on empirical evidence assuming good sails, a good rig, a fair bottom, and a competent crew. They are expressed in seconds per nautical mile.
For example, boat A may have a PHRF of 150 and boat B may have a PHRF of 180. That would mean that boat A ‘owes’ boat B 30 seconds per nm of the race. It is expected that boat A will sail a nautical mile in 30 seconds less than boat B. In a 6 mile buoy race, boat A would need to beat boat B by more than 180 seconds ((180-150) * 6) to be the corrected time winner.
Some PHRF are established by large racing committees (New England PHRF, Lake Michigan PHRF) with much empirical data to consider. You can submit your boat and sail measurements to them and they will calculate your official PHRF rating.
This isn’t necessary for our casual style of racing. Some boats in the fleet have an official PHRF. Most do not. We are able to look up ratings for most boats.
If you are interested in how this plays into our race scoring, please contact me (firstname.lastname@example.org) and I will send you the spreadsheet used to calculate corrected race times.