Boat Modification Rating Changes

Rating adjustments for modifications are considered and applied on an individual basis. The following GUIDELINES are useful for estimating the rating effect of changes, but do not necessarily reflect the actual adjustments that would be made. Sometimes the penalty, or credit, applied is less than the sum of the individual components in these guidelines. This happens most often when two or more of a combination of modifications fall between break points in a complimentary fashion. Other reasons for deviating from the guidelines are usually based on the different ways in which the same change might affect boats of unlike characteristics.

1. Rig Adjustments. Guidelines for ratings adjustment due to rig changes are based on percent change to the calculated Sail Area (SA). SA includes 100% foretriangle and mainsail area, including mainsail roach.

   1. Guide for I alone, J alone, I & J together, or I & P together.

      1. Adjustment = 3 sec/mi for up to 2% change

      2. Adjustment = 6 sec/mi for over 2% up to 4% change

      3. Adjustment = 9 sec/mi for over 4% up to 6% change

      4. Adjustment = 12 sec/mi for over 6% up to 10% change

      5. Adjustment = 15 sec/mi for over 10% up to 15% change

   2. Guide for P alone, E alone, or P & E together (affecting main only):

      1. Adjustment = 3 sec/mi for up to 5% change

      2. Adjustment = 6 sec/mi for over 5% change

   3. Replacement of a yacht's mast with a new mast differing from the original mast in manufacturer, extrusion section, standing rigging, or design, shall cause the yacht to be designated a 'MOD' and individually rated based upon observed performance. Changes to running rigging or backstay adjuster type shall not constitute a modification.

2. Spinnaker, Pole, and Bow Sprit Adjustments. Symmetrical and asymmetrical spinnakers may be used on the same yacht as requested by the owner at the time of application or renewal of the boat's rating, in accordance with fleet policies. A boat choosing to race with both types of spinnakers is subject to a rating penalty for using both types of spinnakers to be determined on a boat by boat basis by the Board of Handicappers.

   1. GUIDE FOR SYMMETRICAL SPINNAKERS AND POLES. No penalty is imposed for the use of symmetrical spinnakers, provided they do not exceed the guidelines defined in the 'Standard Sail and Equipment Guidelines.' These guidelines apply to the largest spinnaker, if more than one is used. These guides are almost always applied as shown. Combinations not shown are considered unusual and must be evaluated by the Board of Handicappers.

      1. Spinnaker Pole Length (SPL) alone; penalty = 3 sec/mi per 10% above unpenalized maximum, not to exceed 6 sec/mi.

      2. Spinnaker girth (G), or maximum width, alone; penalty = 3 sec/mi per 5% above unpenalized maximum, not to exceed 6 sec/mi.

      3. Spinnaker luff length (SL) alone; penalty = 3 sec/mi per 5% above unpenalized maximum, not to exceed 6 sec/mi.

      4. Combined SPL and G penalty, if both match each other (i.e., G is 180% of SPL); penalty = 3 sec/mi for each 5% increase of SPL over 100% of J.

   2. GUIDE FOR ASYMMETRICAL SPINNAKERS, POLES AND BOW SPRITS. No penalty is imposed for the use of asymmetrical spinnakers, provided they do not exceed the guidelines defined in the 'Standard Sail and Equipment Guidelines.' These guidelines apply to the largest asymmetrical spinnaker, if more than one is used.

      1. Asymmetrical Luff (ALU) penalty = 3 sec/mi for up to each 3% variation (+ or -) from unpenalized size range.

      2. Asymmetrical Foot (AF) penalty = 3 sec/mi for up to each 3% addition to unpenalized maximum.

      3. Asymmetrical Mid Girth to Asymmetrical Foot (AMG/AF) ratio penalty = 3 sec/mi for up to each 3% reduction from unpenalized minimum.

         Penalties will be assessed based on:

         1. The displacement, S/A, and hull shape of the boat subject to penalty. 2) The size of the headsail the boat is rated with.

      4. Extended spinnaker poles or Bow Sprit (BS):

         1. Penalty = 3 sec/mi for up to 25% increase over J

         2. Penalty = 6 sec/mi for 26% to 50% increase over J

         3. Penalty for over 50% increase over J shall be evaluated by the Board of Handicappers.

3. Keel Rating Adjustments. Credits and penalties for keel variations or modifications, including boards, may vary from 3 to 12 seconds per mile. The Board of Handicappers will evaluate each case on an individual basis.

4. Engine Rating Adjustments. The rating differential between boats of the same type, on powered by an inboard motor, and the other by an outboard, may vary from 3 to 6 seconds per mile. The actual adjustment depends on the size, weight, and design configuration of the boat. Six (6) seconds per mile is normal. Boats rated without an auxiliary engine shall have a penalty adjustment of 3 or 6 seconds per mile.

5. Roller Furling Genoa/Jib Adjustments. Roller furling credits may be given if a roller furling sail meets material guidelines and has UV protection on the leech and foot. A credit of 9 seconds per mile may be given if the roller furling drum is located wholly above deck level. A credit of 6 seconds per mile may be given if the roller furling drum is located at or below deck level. Roller furling headsails built of a laminated material having continuous woven taffeta outer skins, and have a woven leech and foot cover of at least 4oz UV protected woven material with the roller furling drum located wholly above deck level may be given a credit of 3 seconds..

6. Propeller Rating Adjustments. Credits to ratings may be provided for various types of fixed bladed propellers based on the type, number of blades, and the propellers 'exposure'. The actual adjustment depends on the size, design, number of blades, and exposure as installed in the particular yacht. Evaluation of the design of the propeller will depend upon the intended purpose being primarily to propel the yacht under power (i.e., a cruising design). The recommended guidelines are:

   1. Credits = 12 sec/mi for 3 bladed solid prop on exposed shaft. (Changed from 9 at ADM 2016)

   2. Credits = 9 sec/mi for 2 bladed solid prop on exposed shaft. (Changed from 6 at ADM 2016)

   3. Credits = 9 sec/mi for 2 or 3 bladed solid prop on outboard fixed in well. (Changed from 6 at ADM 2016)

   4. Credits = 9 sec/mi for 3 bladed solid prop in an aperture. (Changed from 6 at ADM 2016)

      No credits are recommended for any propeller on a retracting outboard motor, 2 bladed solid propellers in an aperture, retracting propeller shaft or any 2 or 3 bladed feathering or folding propeller, whether installed on an exposed shaft or in a hull aperture.

7. Mainsail Roach Adjustments. Mainsail roach exceeding the values listed in paragraph 10C of the Standard Sail and Equipment Specifications by up to 5% may receive a –3 sec/mi adjustment. Excessive girth mainsails may be adjusted –6 sec/mi or more depending on the amount of increased girth. In addition, handicappers may review headboard size and if the headboard exceeds 6 inches, or .04E, whichever is larger, an adjustment may be applied.

8. Stored Energy Adjustments. If stored energy is used to help in adjustment of sails, rigs, or to otherwise enhance performance, a rating adjustment may be applied.

9. Roller Furling Mainsail Adjustments. Roller furling mainsail credit may be given if the mainsail can be furled on a drum and spindle mechanism mounted within the mast or boom extrusion. A credit of 3 seconds per mile may be given if the mainsail does not have battens. A credit of 3 seconds per mile may be given for mainsails with full-length battens that furl within the boom. Roller furling mizzen sails may be given a credit of 3 seconds per mile.

   1. For Air Battens – the pressure in the air battens shall not be adjusted during a race.

   2. Roller reefing boom, where the mainsail is rolled around the boom, is not eligible for a rating credit.

10. Headsail Rating Adjustments. Boats designed for the use of overlapping headsails may receive a credit when the LP measurement of the largest headsail is less than 140% of J. The penalty for headsails exceeding 155% of J has not changed. Generally, the adjustments will be as follows:

    1. LP up to 109% - 6 sec/mi. credit.

    2. LP between 110% and 139% - 3 sec/mi. credit.

    3. LP between 140% and 155% - 0 sec/mi. (No Credit)

    4. LP over 155% - 6 sec/mi. penalty.

       Note: Boats designed for non-overlapping jibs are not eligible for this credit.