The Northern California PHRF board introduced "Certified PHRF" ratings, or C-PHRF in 2014. The intent of C-PHRF is to obtain more accurate data to provide more accurate ratings- specifically downwind ratings.
The two numbers on your rating certificate that are most critical to the boat's performance are displacement and waterline length. These numbers are notoriously inaccurate on a typical PHRF application. Most people report "brochure' displacement and waterline length. Actual displacements are almost always heavier than brochure. Effective sailing length can be significantly different than waterline length, depending on slope of the bow and stern overhangs.
In 2010, the NCPHRF committee introduced downwind ratings. This rating is formula based initially. In other words, a formula is used to suggest a rating and the committee then decides whether to use that number directly or apply an adjustment based on performance. More accurate displacement and sailing length data will give the committee a better answer.
Because boats are usually heavier than reported, a certified rating is unlikely to affect your downwind rating in a negative way. You are likely to get 0-6 second more favorable rating. Since the normal PHRF buoy rating is empirical, it is unlikely to change with a C-PHRF certificate; but the committee may be moved to make a change if the displacement is significantly affected.
Why you might want a CPHRF certificate:
In 2016, the Pacific Cup will require a C-PHRF certificate for all boats who wish to compete for the overall Pacific Cup trophy. Possibly in the future other downwind races will start to require C-PHRF certificates.
How to get a CPHRF certificate:
If you have a valid* ORR or IRC certificate, submit a copy of those certificates with your application requesting a C-PHRF. No other action or fee is required. All the information needed is on those certificates. (*"valid" means a current certificate that accurately represents the configuration you will sail under in PHRF.)
If you do not have a valid ORR or IRC certificate, you must have your boat weighed and hull profile measured by a licensed US Sailing measurer. The measurer must measure IRC profile data and will weigh the boat in IRC measurement configuration. IRC configuration is essentially empty, all sails and loose gear removed. Please read our Measurement Preparation Guide and then the Guide to Measurement Process and Ratings for 2016 Pacific Cup Entrants, published by the PacificCup.org
The Pacific Cup will arrange a few specific dates where groups of boats can be measured together, thus significantly reducing cost. These group measurements will be conducted by measurer Dick Horn at Berkeley Marine Center, and are expected to cost $200/boat. A boat that measures solo can expect a normal haul out rate and Dick Horn's hourly rate.
ORR displacements are typically 1-2% higher than IRC because more gear is allowed on board for ORR measurement. The PHRF board will consider the data source and adjust displacement to suit in calculating downwind ratings.