MOUNT GAY 30 RULE revision 3.1
Contents
Part 1 - General
101 Introduction
102 Certificate 103 Measurers
104 Units and Calculation of Measurement 105 Dates
Part 2 - Basic Requirements and Limitations
201 Design
202 Measurement
203 Surface Finish
204 Internal Ballast
205 Special Regulations
206 Crew Weight
Part 3 - Measurement Ashore
301 Presentation
302 Flotation Water Plane
303 Waterline Level Forward
304 Limits of Length
305 Measurement Stations
306 Measurement Ashore
307 Edge of the Working Deck
308 Sheerline
309 Outline
310 Hollows
311 Stem Profile
312 Radius of Curvature
313 Keel
314 Rudders
315 Coach Roof
Part 4 - Engine & Propeller
401 Engine Installation
402 Propeller Installation
403 Fuel Capacity
Part 5 - Measurement Afloat, Weighing, Displacement
501 Lifting
502 Measurement Condition
503 Weighing
504 Measurement Afloat
505 Freeboards Afloat
506 Water Ballast
507 Righting Moment
Part 6 - Accommodation
601 Headroom
602 Berths
603 Cabin Sole
604 Head Compartment
605 Galley
606 Gear Stowage
607 Navigational Area
Part 7 - Rig and Sails
701 Rig Limitations
702 Rig Weight and Center of Gravity
703 Rig Measurement
704 Sail Measurement
705 Jib Measurement
706 Mainsail Measurement
707 Spinnaker Measurement
708 Drifter Measurement
709 Derivation of Sail Area
710 Sail Limitations
711 Restrictions on Setting Sails
Part 8 - Construction
801 Builder's Declaration
802 Panel Weight
Appendix 1 - Permitted Materials
Appendix 2 - Sail Insignia
MOUNT GAY 30 RULE - Part 1 General
Introduction
101.1 - The Mount Gay 30 Rule (M30) is a system of measurement and limitations to classify yachts for competition offshore without time allowances.
101.2 - It is not possible to foresee every eventuality nor to anticipate design innovation. Consequently, the rule may be changed or amended from time to time and the Class reserves the right to interpret clauses in the rule at any time and if necessary, refuse classification.
101.3 - The Class Association shall be responsible for interpreting the rule.
101.4 - The Class Association may permit exemptions for yachts which comply with the Mount Gay Rule Policy but which do not meet all the requirements and limitations of the M30 Rule. Such exemptions shall be granted on a case by case basis and may limit further modification without reconsideration by the Class Association.
Certificates
102.1 - Certificates of Conformity with the Rule will be issued by the Class Association and shall include a Measurement Inventory.
102.2 - To be valid, the Certificate must bear the name and stamp of the issuing authority. The authority for the maintenance and revalidation of the Certificate shall be that in whose area the yacht normally lies.
102.3 - No yacht may have more than one valid M30 Certificate at any one time.
102.4 - A Certificate must be signed by the owner who has primary responsibility for presenting the yacht for measurement and ensuring that the yacht complies with the Rule. A Certificate is automatically invalid upon change of ownership, or a change to the yacht that affects the Rule measurements.
102.5 - When the Issuing Authority has reasonable evidence that, whether or not by her own fault, a yacht does not conform to her Certificate, the Certificate shall be withdrawn and the owner informed in writing.
102.6 - When the Issuing Authority intends to withdraw a Certificate while the yacht is under the jurisdiction of a race committee, it shall report the matter to the race committee, which will proceed under the provisions of the ISAF.
102.7 - The Certificate will normally be valid until 31st December of the year of issue.
102.8 - Any valid Certificate is available to any person on payment of a copy fee.
102.9 - A copy of the current Certificate shall always be on board the yacht.
Measurers
103.1 - Only measurers specifically appointed by the Class Association shall measure yachts under the M30 Rule.
103.2 - Neither a measurer nor his assistant shall participate in the measurement of the yacht or its sails wholly or partly owned, designed or built by himself or in which he is an interested party or in which he has acted as a consultant, whether or not any payment is involved.
Units and Calculation
104.1 - Linear measurements, including headboards and battens, shall be of taken in meters to three places of decimals. Dimensions of sails shall be taken in meters to two places of decimals.
104.2 - Units of weight shall be recorded in kilograms to the nearest I0kgs, except that weights below 500kgs shall be to the nearest kilogram.
104.3 - Intermediate stages of calculations shall use the full values but resulting areas or volumes shall be recorded on the certificate to two places of decimals.
Dates
105.1 - The Age Date shall be the date the yacht was first measured afloat.
105.2 - The Hull Date shall be the date of measurement ashore of the yacht or the first yacht of a production series. Modifications requiring remeasurement of the hull will attract a new Hull Date.
MOU NT GAY 30 RULE - Part 2 Basic Requirements and Limitations
Design
201.1 - Owners should note that the Mount Gay 30 Rule contains a series of absolute limits and there are no provisions in the Rule for tradeoffs.
201.2 - As an example an increase in weight will affect the location of Freeboard Reference Points and these may compromise the values of Deck Height Offsets.
201.3 - Compliance with the M30 Rule does not imply any approval of the structural integrity of the yacht.
Measurement
202.1 - The yacht shall be measured ashore (Part 3 & 4); weighed and measured afloat (Part 5 & 6).
202.2 - The keel shall also be weighed and measured prior to fitting to the canoe body (Part 3).
202.3 - The rig shall be measured prior to stepping in the yacht (Part 7).
Surface Finish
203 - The surface of the hull and appendages shall not be textured or coated with the intention of reducing drag, other than a conventional painted finish.
Internal Ballast
204.1 - Internal ballast not exceeding a total of 40kg may be located at one or more locations selected by the owner, which shall be recorded on the measurement inventory.
204.2 - The ballast shall be fixed and sealed to the hull to the satisfaction of the measurer.
204.3 - Exceptionally, ISAF 22.2 and 57 shall be waived in respect of water ballast only.
Special Regulations
205.1 - Irrespective of the requirements of a Notice of Race or Sailing instructions, the yacht shall conform in all respects to the ORC Special Regulations Governing Offshore Racing, Parts 5 & 6 to Category 2.
205.2 - Cockpits (ORC Special Regulations 6.21-6.25).
205.2a - A cockpit is defined as any deck surface below the level of the local edge of the working deck forward of AFS.
205.2b - The total Cockpit Area (CPA) shall not exceed 5.00m2, measured at the height of the local working deck.
205.2c - The Cockpit Sole Height (CPH), including any extension abaft AFS, shall be not less than 0.180m above FWP.
205.2d - The total Cockpit Volume (CPV) shall not be greater than 2.000m3.
205.3 - Anchors (ORC Special Regulations 8.3)
205.3a - The yacht shall carry an anchor of minimum weight 9kg and at least 4.500m of 8mm chain.
205.3b - The stowage of the anchor and chain shall be recorded on the measurement inventory.
205.3c - For races requiring an additional anchor, it shall be carried forward of the mast.
Crew Weight
206 - Total crew weight shall not exceed 350kg, except that when water ballast tanks are not fitted, or emptied and the system rendered inoperable, the crew weight may increase to 575kg.
MOUNT GAY 30 RULE - Part 3 Hull Measurement
Presentation
301.1 - The yacht shall be set up on a reasonably level hard surface, level athwartships and on the Flotation Waterline Plane declared by the designer.
301.2 - The yacht shall be firmly checked, both fore and aft and athwartships.
301.3 - The weight of the yacht shall rest on the keel except as is necessary to chock the yacht.
Flotation Waterline Plane
302 - Flotation Waterline Plane (FWP) is defined as the waterline of the yacht in the afloat condition defined in Clause 502.
Waterline Level
303.1 - Waterline Level Forward (WLF) is defined as the intersection of FWP with the centerline of the stem. A permanent datum mark, parallel with FWP, not less that 0.025m high and 0.100m long, shall be painted in a contrasting color on each side of the canoe body at the stem with the lower edge passing through the datum point.
303.2 - The 0.100m buttock line at the After Freeboard Station (305.3) shall lie on or above FWP.
Limits of Length
304 - The limit of length shall be defined as a vertical, transverse section located at the extremity of the canoe body, forward (LLF) and aft (LLA), excluding any fittings, protective additions, rudders and their associated fittings. Length Overall (LOA) is the distance between LLF and LLA.
Measurement Stations
305 - There shall be three measurement stations on vertical transverse sections of the yacht:
305.1 - Forward Freeboard Station (FFS) shall pass through a point 0.050m above FWP on the centerline of the stem.
305.2 - Mid Length Station (MLS) shall be established at a distance 55% of LM (306.4) from FFS.
305.3 - After Freeboard Station (AFS) shall pass through a point 5% of LM (306.4) forward of LLA.
Measurement Ashore
306.1 - Maximum Beam (BMAX) of the yacht shall be recorded as BMAX and shall not exceed 3.350m.
306.2 - Beam Forward (BF) The beam of the yacht between FRP (306.5) at FFS (305.1) shall be recorded as BF and shall not exceed 0.500m.
306.3 - Beam Aft (BA)· The maximum beam at AFS (305.3) shall not exceed 90% of BMAX.
306.4 - Measured Length (LM) shall be recorded as the horizontal distance from FFS (305.1) to LLA (304). LM shall not exceed 9.144m.
306.5 - Freeboard Reference Points (FRP) shall be established at the measurement stations at FFS, MLS and AFS (305.3) 0.920m, 0.765m and 0.650m above FWP (302) respectively. FRP at each station shall be permanently marked on both sides of the canoe body, with a screw head or indentation.
306.6 - Forward Overhang (FO) shall be the horizontal distance from FFS (305.1) to the centerline of the stem at the height of FRP on FFS. FO shall not exceed 0.400m.
306.7 - Deck Height Offset (DH01..3) shall be the vertical distance from the edge of working deck (307) to FRP (306.5) and shall not be less than 0.100m. The values DH01..3 shall be measured port and starboard at the three measurement stations, FFS, MLS and AFS (305.3) and the mean values recorded.
Edge of the Working Deck
307.1 - The edge of the working deck shall be defined as the most outboard point on the deck at which any hull deck joint radius commences. It shall not be more than 0.100m from the outline of the canoe body in plan, except across the top of the transom.
307.2 - The hull deck joint radius in any transverse section shall not exceed 0.100m. Otherwise there shall be no tumblehome.
Sheerline
308 - The sheer of the yacht in elevation at the edge of the working deck between a point 0.200m abaft the LLF (304) and AFS (305.3) shall be a fair continuous curve whose minimum radius of curvature shall not be less than 10.000m.
Outline
309 - At any point, the outline of the canoe body in plan shall not be concave. From 0.200m abaft LLF (304) to AFS (305.3) the outline shall be a fair, continuous curve whose minimum radius of curvature shall not be less than 8.000m.
Hollows
310 - There shall be no hollows in the surface of the hull except:
310.1 - On the hull deck joint radius.
310.2 - Forward of 2.500m from LLF (304) not exceeding a depth of 0.050m over a length of 1.000m.
310.3 - Within the 0.100m buttocks from 2.500m abaft LLF (304) to LLA (304).
310.4 - Within a rectangle on the surface of the hull 0.300m wide, whose major axis, not exceeding 125% of the keel mid-chord in length, is upon the centerline of the hull.
310.5 - Within a rectangle on the surface of the hull 0.200m wide, whose major axis, not exceeding 125% of the maximum immersed rudder chord in length, shall pass through the centerline of the rudder stock.
310.6 - Where the cockpit opens aft to the sea.
310.7 - No point on the canoe body, in any transverse section, may be lower than any point nearer to the centerline.
310.8 - At a construction joint between the hull and the transom, not exceeding 0.050m in depth.
Stem Profile
311 - No part of the canoe body shall be forward of a straight line passing through the FFS (305.1) point and LLF (304). No fixed fitting may extend more than 0.050m forward of this line.
Hull Radius of Curvature
312.1 - Radius of curvature shall be checked normal to the local hull surface.
312.2 - In any transverse section in way of the water ballast tanks, the radius of curvature, from the sheerline to the 0.150m buttock, shall not be less than 0.500m, excluding the hull deck joint radius.
312.3 - A chine built yacht is permitted provided that the chines have a radius of curvature less than 0.030m running continuously from 2.500m abaft FFS (305.1) to AFS (305.3), or disappearing into the centerline of the hull. A chine shall have an included angle greater than 135 degrees and any batten girth shall comply with 312.2.
312.4 - In profile, within 3.000m of LLA (304) the minimum radius of curvature of the 0.150m buttock shall not be less than 10.000m.
Keel
313.1 - The keel assembly is defined as all the component parts of the keel, including fixings, which may be separated from the canoe body. For the avoidance of doubt it includes keel bolts, nuts, washers and spacers.
313.2 - Keel weight (KW) shall not be less than 900kg nor exceed 1150kg.
313.3 - Vertical Center of Gravity of the keel assembly (KG) shall not be more than 1.500m below FWP (302).
313.4 - No part of the keel below the canoe body shall be less than 0.080m or more than 1.000m athwartships nor more than 2.000m fore and aft.
313.5 - Draft Measured (DMS) shall be the maximum draft below FWP and shall not exceed 1.950m.
Rudders
314.1 - Of the appendages, only rudders shall be movable and the only movement allowed shall be rotation about one axis.
314.2 - The movable part shall be one piece not exceeding 0.075m in thickness.
314.3 - The axis of rotation of any rudder may lie forward of the LLA (304) but not more than 0.075m abaft it when measured on the waterplane of the aftermost point of the hull.
314.4 - No more than two rudders may be used, symmetrically placed about the yacht's centerline, on the same transverse section, abaft the after edge of the keel.
Coach Roof
315.1 - A coach roof is defined as any deck surface not less than 1.200m above FWP (302), which lies more than 2.500m from LLF (304).
315.2 - The Coach Roof Area (CRA) shall be not less than 2.800m2, over Coachroof Length (CRL), not less than 2.000m.
MOUNT CAY 30 RULE - Part 4 Engine & Propeller
Engine Installation
401.1 - A production water cooled marine diesel engine of at least 9 rated H.P shall be installed, with the crankshaft fore and aft and conforming to the following conditions:
401.2 - The installation can be demonstrated to be capable of driving the yacht at a speed not less than 6.0 knots in calm water, with 350kgs crew weight, all equipment excluding stores on board and with 300kgs water in the ballast tanks.
401.3 - The engine and propeller shall be ready for use at all times.
401.4 - Engine Dry Weight (EW) shall be the dry weight of the propulsion engine, taken from the manufacturer's catalogue. Reverse and reduction gearboxes and engine driven auxiliaries shall be included in the engine dry weight. EW shall not be less than 75kgs.
401.5 - Engine Weight Distance (EWD) shall be the horizontal distance of the center of the engine cylinder block from LLF. EWD shall be more than 6.000m.
Propeller Installation
402.1 - The propeller shall be 2 bladed and may be fixed or folding driven by an exposed shaft, supported by a conventional strut, or series production strut drive. The propeller shall not be retracted, housed or shielded except by the strut and shall conform to the following limits:
402.2 - Propeller Diameter (PRD) shall be the maximum diameter of the propeller disc. PRD shall not be less than 0.350m.
402.3 - Propeller Hub Diameter (PHD) shall be the minimum projected dimension of the propeller hub. PHD shall not be less than 0.040m.
402.4 - The propeller shaft shall be of constant, circular cross section, except in way of couplings and the propeller hub.
402.5 - Propeller Shaft Diameter (PSD) shall be the diameter of the shaft exposed to the water flow. PSD shall not be less than 0.022m.
402.6 - The Strut Thickness (ST1) shall be the minimum projected thickness of the strut at any point between the hull and the shaft line. ST1 shall not be less than 0.025m.
402.7 - Strut Width (ST2) shall be the width of the strut parallel to the shaft at any point between the hull and the shaft line. ST2 shall not be less than 0.080m or more than 0.125m.
402.8 - Strut Hub Diameter (SHD) shall be the minimum projected dimension of the strut hub. SHD shall not be less than 0.055m for an exposed shaft installation or 0.085m for a strut drive.
Fuel Capacity
403.1 - The minimum capacity of the fuel tank shall be 45 liters.
403.2 - It shall be equipped with a sight gauge or other system such that it may be checked empty when the yacht is weighed (502).
403.3 - Its location shall be recorded on the measurement inventory.
MOUNT GAY 30 RULE - Part 5 Measurement Afloat, Weighing & Displacement
Lifting
501.1 - The yacht shall be fitted with tackle such that it may be suspended from a single point, in essentially level trim, with ballast tanks full or empty. Lifting tackle need not be on board for racing.
502.2 - For the avoidance of doubt, the use of slings, which encompass the canoe body, is not permitted when the yacht is weighed.
Measurement Condition
502.1 - The yacht shall be ready for sailing with water ballast tanks (506) empty, the internal ballast (204.1), mast, rigging, batteries, and all fixed propulsion, radio and navigation equipment installed and recorded on a measurement inventory.
502.2 - Crew, boom, poles, bowsprit, sails, fuel, water, anchors, chains, warps, halyards, sheets, guys, deck gear and all movable stores and equipment shall be removed.
Weighing
503.1 - The yacht shall be weighed on a single, certified load cell.
503.2 - Displacement (DSPL) = Cell Weight, corrected for the weight of strops (501).
503.3 - In the condition of 502, DSPL shall not be less than 2300kg.
Measurement Afloat
504.1 - Immediately after weighing, the yacht shall be placed in the water.
504.2 - Specific Gravity (SG) of the water, taken approximately 0.300m below the surface shall be recorded as SG.
504.3 - FWP Measurement. Floating in water of specific gravity 1.015 and in the condition of 502, the WLF datum point, (303.1) shall lie at the water surface.
504.4 – Sink. If the specific gravity of the water is different from 1.015, all flotation data shall be corrected by 0.20mm per 0.001 variation in SG from 1.015.