PHRF of the Chesapeake, Inc.

Making Measurements for PHRF Applications

      The measurements as reported on a yachts rating application form are critical to the establishment of the PHRF rating.   The responsibility for supplying accurate measurements rests solely with the owner of the boat.   Although builder-supplied information can and should be consulted, particularly with regard to hull measurements, considerable variances between yachts of the same class can be possible.   Variances in rig and spinnaker pole, dimensions are quite possible, and common, which could result in the rating being declared invalid if the owner supplied incorrect information.   To establish better understanding of, and consistency in the reported measurements, some definitions, and guidelines are provided, along with the unpenalized PHRF limitations, if applicable.   

See Sail and Rigging Measurements for example showing measurement locations  

MEAS

LIMITS

DEFINITIONS

LOA

 

Length Over All (LOA) of the hull.  Note bowsprit and or boomkins separately.

LWL

 

Loaded Water Line (LWL).  If unmeasured, use brochure LWL.

BEAM

 

Maximum beam of the vessel.

DRAFT

 

Deepest draft of hull.  If centerboard or daggerboard yacht include draft with board up and down.

DISPL

 

Vessel displacement in pounds without crew, water, fuel, stores aboard.   If unmeasured use brochure DISPL.

BAL

 

Ballast (BAL) of vessel in pounds.  Note any additions or deletions from standard and the location.

J

 

Distance perpendicular from fore side of mast line to the point of intersection of the forestay with deck.

I

 

Height of fore triangle.  Measured from deck sheer line abeam the mast to highest point of sail attachment.

P

 

Luff length of mainsail measured from boom to head board in its highest position.

E

 

Foot length of mainsail measured from the mast to clew in its most outboard position.

P2

 

Luff length of mizzen (two masted boats only) measured same as “P”.

E2

 

Foot length of mizzen (two masted boats only) measured same as “E”.

SH

100% “I”

Spinnaker Hoist (SH) measured from the deck sheer line abeam the mast to the highest point of spinnaker attachment

LP

 

Length of the Perpendicular (LP).  Distance perpendicular from the luff to the clew of the largest jib or genoa.

LP%

 155%

“LP” length expressed as a percentage of  “J”.

SPL

 

Spinnaker (or whisker) Pole Length (SPL) measured with the pole in fitting and in a horizontal position athwartship.

SPL%

100%

“SPL” length expressed as a percentage of “J”.

BS

100% “J”

Distance perpendicular from the fore side of mast line to the point of intersection with the outermost point of sail attachment with the bow sprit.

G

 

Spinnaker maximum Girth (G, also SMW), measured luff to luff.  Fold on centerline, measure width, multiply by 2. 

G%

180%

“G” measurement expressed as a percentage of “J”.

SL

 

Length of Spinnaker Luff (SL) measured along luff tape from head to clew on the largest spinnaker.

SL%

100%

“SL” measurement expressed as a percentage of .95 times square root of (“I” squared + “J” squared)

ALU

 

Length of asymmetric spinnaker luff measured along longest luff tape from head to tack.

ALU%

 <110%

“ALU” measurement expressed as a percentage of the square root of (“SH” squared + “BS” squared)

ALE

 

Length of asymmetric spinnaker leech measured along shortest tape from head to clew.

AF

 

Length of asymmetric spinnaker foot measured along foot tape from clew to tack.

AF%

180%

“AF” length expressed as a percentage of  “BS”.

AMG

 

Asymmetrical maximum girth (AMG) measured from mid-point on luff to to mid-point on leech on asymmetric sail.

AMG%

>80%

“AMG” width expressed as a percentage of  “AF”.

 ROLLER FURLING CREDIT REQUIREMENTS AND LIMITATIONS   (This information is required on the application form).

        a.     Whether the furling drum is completely above deck level, or partially or completely below deck level.

        b.     All RF headsails must comply with paragraph 17 of the Standard Sail and Equipment Specifications.  

        c.     All headsails must be tacked above the furling drum and have the head secured to the bottom of the head swivel.

d.        Describe the: Furling System Type; Headsail Material; Year sail was built, and type of UV protection on RF headsail.

 FIXED PROPELLLER CREDIT REQUIREMENTS AND LIMITATIONS  (This information is required if you are requesting a prop credit).   To be eligible for rating credit, propellers must be of fixed design, with no folding or feathering mechanisms.    The information required below must be provided with the request for credit, and is in addition to checking the proper block on the renewal or application forms.   This information is required to assess each yacht’s propeller, and propeller installation, for approval of rating credit.   The diagram included is intended to show approximate examples of exposed, and aperture installations only.   Individual yacht installations may vary.

a.        A detailed diagram, or photo, of the propeller installation must accompany all requests for fixed prop credits.

b.        You must specify the type of propeller installation

1)        _______ Aperture or,

2)        _______ Exposed

c.        ______ Specify the number of blades of the fixed propeller

d.        ______  Specify the diameter of the propeller in inches.

e.        ______  Specify the pitch of the propeller in inches

f.         ______  Specify the minimum distance from the propeller to the trailing edge of the keel in feet (EXP, in diagram).

g.        ______  Specify the length of the propeller shaft exposed (from hull/keel exit to propeller in feet (SHAFT in diagram).

 

EXPLAIN ANY MODIFICATIONS.  (Report any variations from standard hull, rig, mast, keel, etc. on separate sheet)