Rating & Handicapping

Our handicapping fomula is the 1974 Off Soundings Club Rating Rule:

Rating in feet = [ {L + (2 * MSA * RA)} / 2.5 ]*PA
where L = PL +/- BC
PL = ( LOA + LWL ) / 2
BC = 2 * ( LOA / 4 - beam )
MSA = Measured sail area
PA = Propeller Allowance
RA = Rig Allowance

The critical elements of this formula are the boat’s dimensions, sail area, prop and rig type. Measured Sail Area is the theoretical area available for lowers, and reflects the rig type and size, not the boat’s sail inventory. There is no provision for spinnakers, topsails, etc. so boats carrying these sails have an advantage. Each boat’s handicap is computed anew every year, so any errors of transcription or computation are not likely to persist from year to year.

Measurements

Roughly speaking, these are measured:

P = Main leech
B = Main foot
H = Luff (gaff main)
G = Head (gaff main)
B1 = Fore boom
P1 = Fore boom to fore truck
P3 = Fore boom to main truck
J = Jib foot
LP = Jib diagonal
P2 = Deck to headstay
LOA = Length on deck

Measured Sail Area Formulas

Bermuda Main: PB / 2
Gaff Main: [ ( B * H ) + ( G * D ) ] / 2 where D = .96 [ ( B * B ) + ( H * H ) ]
Area Between Masts (ABM): .75 * ( P1 + P3 ) / 2 * B1
Jib (no overlap): ( P2 * J ) / 2
Overlapping Jib: 0.5 ( P2 * J ) + [ ALH - 0.5 ( P2 * J ) ] + 0.2 J ) ] + 0.2 J ( P2 - 2J ) where ALH = [ ( P2 * J ) / 2 ] * LP
Sail areas for Main, ABM and Jib are totalled. Three- or four-masted vessels have multiple ABMs.

Rating Adjustments: Penalties and Credits

This is a fun race, so a penalty is applied to prior winners: the first vessel in its class is assigned a 10% penalty in its next race; the second vessel in its class is assigned a 5% penalty in its next race. If a schooner does not start in a given year, her penalty carries forward until she races again.

If a vessel consistently performs well outside the range of her class (for instance, excessive displacement for her rated length), the race committee reserves the right to make appropriate adjustments in allowances or class placement until the vessel becomes competitive. For example, Norfolk Rebel receives credit for the drag of her tires in the water when heeled. The first time a schooner competes, she normally races without adjustment. Any questions regarding ratings should be directed to the race committee.

Fleets and Classes

Classes are determined by rated length before penalties or credits are applied. (The race committee reserves the right to determine classing by rig, displacement, performance or other criteria, as well as rated length.) Classes have changed over the years, as has the course length for each class. Large classes may be split.

Thimble Shoal Fleet (127 nm course)
Class AA rates 50 feet or more
Class A rates from 40 to less than 50 feet

Windmill Point Fleet (80 nm course)
Class B rates from 30 to less than 40 feet
Class C rates less than 30 feet

Corrected Time Computation (Seconds per Mile Allowance)

We use the North American Yacht Racing Union Table of Allowances, which uses the nearest tenth of a foot rated length.

Allowance = (2160/√rated length) - 176.36
Allowances taken from the Table of Allowances (1999 race and earlier) vary slightly from the result of this formula (used for all entrants starting in 2000). To compute a vessel's Allowance, multiply the result of this formula by the course length, and convert the answer to hours, minutes and seconds. This amount will be applied to a vessel's Elapsed Time to determine its Corrected Time.

An example of how to handicap the competition:
Vessel A rates 32.40 feet and 203.11 sec/mile
Vessel B rates 45.60 feet and 143.51 sec/mile
Multiply allowance by distance in nautical miles (Thimble Shoal): 127
Vessel B (25,795.35 seconds) = 7:09:55
Vessel A (18,225.57 seconds) = 5:03:45
Difference = 2:06:10
Vessel B (longer) must beat Vessel A (shorter) by more than 2 hours, 6 minutes, 10 seconds to win on corrected time at Thimble Shoal.