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Base PHRF Handicap Numbers

To:  Race Participants

For the past many years, the Boon Island Race has been conducted using “base PHRF handicap numbers” for the boats participating in the race. Base numbers assume a boat to be in “as-built” configuration.

The base number does not take into consideration differences in pre market or after market options such as prop design, spinnaker configuration, boom length adjustments, standing rigging adjustments, etc.

However, some of the boats participating in the Boon Island race do qualify for these adjustments. Some adjustments increase the handicap number, such as three or four bladed props, while others detract from the handicap rating, such as folding props, added boom length, added rig height, full spinnaker design, etc.

We have had one or more boats participating in past Boon Island Races that have PHRF Certification. Such certification has been granted by PHRF based on a detailed review of the options employed on a given boat. In other words, design adjustments were taken into consideration

This year we would like to put all boats on a more even footing by making appropriate adjustments to the base PHRF rating.

To do this, the race committee will need some additional information about your boats to determine the proper handicap.

In the interest of not making this process too complicated, the committee asks that adjustments be made only for prop design and sail design. These seem to be the most common alterations of boats in out fleet.

A three or four bladed prop would qualify for an adjustment of +6-+9 seconds. Similarly, an outboard fixed in a well with a two bladed prop would qualify for a +6 second adjustment. A collapsible or folding prop would qualify for an adjustment of -3 seconds.

As to sail design, recreational sails, meaning one asymmetrical spinnaker and regular sails, meaning no Kevlar or other high tech sailcloth, would qualify for a +6 second adjustment.
Please see the charts below to determine your adjustments.

These don’t seem like big numbers, but when applied to a 26-mile race, an adjustment of +12 seconds amounts to about a 5-minute advantage. We’ve had many races decided by less than a 5-minute difference.

When you submit your registration form for the 2022 Boon Island Race, please include specifications both on the prop design for your boat and the sail configuration. This information will be incorporated into determining your adjusted PHRF rating.

Questions can be directed to Peter Hatch (

See attached PHRF New England “adjustments” page
It can also be viewed at


1 June 2014

The following are adjustments that PHRF-NE normally makes to a base boat for non standard equipment.

The base boat is assumed to in as-built configuration with a 155% genoa (unless only a non-overlapping sail can be carried), a spinnaker/whisker pole length equal to J, a spinnaker width equal to 1.8 times J, a spinnaker height equal to .95 times the square root of I squared plus J squared, and either a folding or feathering propeller on an exposed shaft, a two bladed solid propeller in an aperture, or an outboard motor sufficent to drive the boat at the square root of the waterline length in knots. IMS sail definitions apply, particularly with respect to mainsail girths for other than One Design boats. Sprit boats will be handicapped in the configuration shown on the application. If the boat differs from the base boat, the following adjustments apply:
Boone Island Race Adjustments will be for the following 2 criteria, Auxiliary Power and Recreation Adjustment.


Two bladed solid propeller on an exposed shaft    
+6 sec/mile

Three bladed solid propeller on an exposed shaft


Three bladed solid propeller in an aperture


Two bladed feathering propeller in an aperture


Three bladed feathering propeller in an aperture


Outboard fixed in well with two bladed solid propeller


Inboard with exposed shaft in place of outboard

+3 to +9


Limited inventory, above deck jib roller furling, polyester, pentex, or mylar only in working sails, no exotic sail materials such as kevlar, spectra, technora, etc..
A maximum of:
One nylon spinnaker
One jib with Lp > 110%
One jib with Lp =< 110%
Heavy weather jibs and storm sails are allowed. Staysails are allowed if the boat has a true cutter rig and the staysail is used upwind. Staysails are allowed if they are only used as part of the heavy weather/storm sail configuration.

Working roller furling with sail attached to swivel and above deck drum are required. If the drum is below deck, the credit will be halved. Boats that come with built in roller furling are not eligible for this credit. In cases where the intent of this adjustment is not honored, the credit will be denied. The credit may also be reduced on performance boats to 3 seconds per mile. Special racing roller furling sails are not allowed. As a rule of thumb, the foot skirt should not exceed 3 percent of the foot length in depth. If the boat is cutter rigged, the staysail must also be roller furling and be capable of being used upwind.

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