# R Class Specifications and Restrictions

Specifications and Restrictions (Rules) for the R Class Skiff

# New Zealand "R" Class Skiff Rules

**Specifications**

Any amendments to these specifications shall, after being approved by the national conference, be confirmed by a vote of all boat owners registered annually on the NZ R Class Register.

A two thirds majority is required to confirm the amendments to these specifications.

If a two thirds majority is not achieved the specification amendments shall not be resubmitted until either: a period of five years has elapsed, or the National Conference votes to include the amendment on three consecutive years.

**Restrictions**

**1.0 Round bilge**- Rule Deleted - Sept 2004.

**2.0 Length**- 2.1 The length must not exceed 3.9 metres measured to the extreme length of the hull between perpendiculars to the waterline.
- 2.2 Deck extensions, bowsprits, rudder frames or outriggers do not form part of the hull.
- 2.3 The stem shall be clear to within 60 mm of its base. (This restriction shall apply to all new boats, or boats altered after 30 July 1994)
- 2.4 No part of 2.2 above shall attach to the hull any lower than 50mm. to the keel line or projection thereof.

**3.0 Beam**- 3.1 The extreme beam measured to the outside of the hull must not be less than 1.4 metres measured between perpendiculars to the waterline.
- 3.2 The full width of the forward section of the boat, measured across the boat, 300mm back from the stem must not exceed 700mm.

**4.0 Crew**- 4.1 A minimum crew of two must be carried.
- 4.2 Trapezes and other forms of supporting the crew beyond the gunwale may be used, but must be so constructed so as not to cause serious injury to boats or persons. This rule shall be to the satisfaction of the measurer.

**5.0 Mainsail Release**- 5.1 Mainsails shall be able to be lowered on the water. The hoist must not be lashed, and where a shackle is used a shackle tool must be carried on board.

**6.0 Outriggers**- 6.1 Sails may be sheeted or tacked over or through an outrigger.

**7.0 Safety**- 7.1 All boats must comply with the YNZ safety regulations except for R class rules.

**8.0 Sail Numbers**- 8.1 The National secretary maintains the national register of sail numbers and allocates all numbers.
- 8.2 Spinnakers shall not need sail numbers.

**9.0 Sail Measuring Procedure**

Download Measurement Form (Excel 52k)- 9.1 General
- 9.1.1
**The objective is to measure the maximum surface area of the working sails as fairly as possible. If the recommended technique should prove inadequate the measurer shall make appropriate adjustments to achieve this objective**. - 9.1.2 Working sails may be measured wet or dry and shall not exceed 13.0 sq metres. Spinnakers may be dry when measured.
- 9.1.3 Working sails shall be measured on the floor and stretched out to measure the surface area of the cloth. Battens shall be set to racing tension.
- 9.1.4 The jib shall be stretched sufficiently to remove wrinkles down the luff, then smoothed out so that as much cloth as possible lies on the floor.
- 9.1.5 The main shall be stretched so that the foot, leech and luff are tight with no significant wrinkles.
- 9.1.6 Leech and foot cords shall be freed or fixed at a maximum distance.
- 9.1.7 All measurements are in metric.
- 9.1.8 All sails shall be marked near the tack point with the measured area/perimeter, date measured and measurer's initials.

- 9.1.1
- 9.2 Definitions
- 9.2.1 The peak shall be the uppermost point of the intersection of the luff with the leech.
- 9.2.2 The tack point shall be the lowermost point of the intersection of the luff with the foot.
- 9.2.3 The clew point shall be the intersection of the foot with the leech.
- 9.2.4 The luff length (M Luff) or (J Luff) is the distance between the peak and the tack point.
- 9.2.5 The leech length (M Leech) or (J Leech) is the distance between the peak and the clew point.
- 9.2.6 The Foot length (M Foot) or (J Foot) is the distance between the tack point and the clew point.

- 9.3 Mainsail Measurement
- 9.3.1 The main triangle area (MA) = M Leech x 1/2 MT to L Note if (M luff)is longer than (M Leech) use (MA) = M Luff x 1/2 M Clew to luff
- 9.3.2 Any roach or hollow in the luff or foot is measured at the maximum point and calculated using:

luff MAlf = M Lex*x*2/3*x*M Luff

Foot MAf = M fex*x*2/3 M Foot - 9.3.3 The leech roach is measured by dividing M leech into 10 equal parts and measuring the distances at each point to the leech at right angles to the line from the tack and clew points, Then calculating using MAr = L Sum (R1-R10) /10 x M Leech
- 9.3.4 If the mainsail does not fully enclose the mast, then the mast less fittings but including the sail track shall be able to pass through a circle of 100 mm diameter. Any excess shall be measured by multiplying the length of the mast by the maximum excess dimension.

ie MAm = Mast length x excess mast section. - 9.3.5 If the mainsail does not fully enclose the boom then the boom less fittings but including the sail track shall be able to pass through a circle of 150 mm diameter. Any excess shall be measured by multiplying the length of the boom by the maximum excess dimension.

ie MAb = Boom length x excess boom section. - 9.3.6 The total mainsail area MA total

Is the sum of the main triangle (MA)

Plus the luff roach/hollow (MAlf)

Plus the foot roach/hollow (MAf)

Plus the leech roach (MAr)

Plus any excess mast area (MAm)

Plus any excess boom area (MAb)

- 9.4 Jib Measurements
- 9.4.1 The Jib triangle area (JA) = J luff x 1/2 the shortest distance from a line joining the peak and the tack points, to the clew (JL to C)

ie. (JA) = J Luff x 1/2 J luff to Clew - 9.4.2 Any roach or hollow in the Leech, luff or foot is measured at the maximum point and calculated using:

Leech JAlh = Jhex x 2/3 Jlh

luff JAlf = Jlex x 2/3 Jluff

Foot JAf = Jfex x 2/3 Jfoot

Note: Any of the above hollow areas are deducted. - 9.4.3 If a fore spar is used the area of the fore spar shall be calculated as the length of the fore spar (Fl) multiplied by the maximum fore aft width (Fw) giving a fore spar area (FA)

ie. FA = Fl x Fw - 9.4.4 If a fore boom is used the area of the fore boom shall be calculated as the length of the fore boom (FbI) multiplied by the maximum depth (Fbd) giving a fore spar area (FbA)

ie. FbA = Fbl x Fbd - 9.4.5 The total Jib area JA total

Is the sum of the Jib triangle (JA)

Plus the luff roach/hollow (JAlf)

Plus the foot roach/hollow (JAf)

Plus the leech roach/hollow (JAlh)

Plus the area of the fore spar (FA)

Plus the area of the fore boom (FbA)

- 9.4.1 The Jib triangle area (JA) = J luff x 1/2 the shortest distance from a line joining the peak and the tack points, to the clew (JL to C)
- 9.5 Total Working sail area
- 9.5.1 The total working sail area shall be the sum of the total mainsail area (MA total) Plus the total Jib Area (JA total)
- 9.5.2 Total working sail area shall not exceed 13.0 sq metres.

- 9.6 Spinnakers
- 9.6.1 All spinnakers shall be triangular when suspended.
- 9.6.2 Spinnakers shall be measured when stretched firmly and wrinkle free at each corner with edge cords released.
- 9.6.3 The perimeter shall be measured by taking the luff length, the leach length and the foot length and adding these three lengths together.
- 9.6.4 The calculated perimeter shall not exceed 20 metres.

- 9.1 General