FROM OUR YEARBOOK:
3.0 AMS and SMS Measurement Rules
3.1 Principles and Administration
3.1.1 It is the responsibility of all owners to work within the spirit of the Australian and Sportsboat Measurement Systems and no attempt should be made to achieve a better rating by exploiting, in an artificial manner, the elements of this system. This system can only work to the benefit of all participants if it is used in a fair and equal manner by all boat owners.
3.1.2 All measurements must be taken according to these guidelines and boat owners are duty
bound to declare any matters that may affect the rating.
3.1.3 The measurements and the application form must be approved and signed (or electronically submitted) by the authorised Measurer and the boat owner.
3.1.4 Ratings are determined by the YRSA Office in good faith and to the best of the ability of the system. No responsibility is taken for the accuracy of the rating, except that the committee shall attempt to provide ratings that are fair and reasonable and should enable participants to compete in an equal manner as outlined in this document.
3.1.5 YRSA attempts to minimise the expense of sailing and through the use of volunteers, ensures that rating costs are minimised.
3.1.6 All yachts sailing under the AMS or SMS rule shall be responsible for obtaining a valid certificate and whilst every effort will be made to provide certificates in a timely manner, a lead-time of two weeks should be allowed from the date of submission of the data to the Rating Office. Expedited certificates within 5 working days may be provided for an additional fee.
3.1.7 The AMS and SMS algorithm will be updated when new or better data is obtained and whilst this procedure will occur on a regular basis the Committee reserves the right to vary measurement systems if the need arises.
3.1.8 The Ratings and certificates provided under the AMS and SMS are protected by copyright.
Requests for interpretations of the AMS or SMS rules should be made in writing as detailed in paragraph 2.13
3.1.9 It should be noted that the issue of a certificate does not imply that the vessel meets the ISAF, National Authority, Club or Notice of Race safety requirements. It is the
responsibility of the owner to ensure that these requirements are met and that the boat is suitable, sound and is properly crewed for the conditions encountered.
3.2 General Measurement Rules
3.2.1 Sails must be clean and dry and should be tensioned to remove wrinkles along the line being measured.
3.2.2 Dimensions shall be in metric units to the nearest centimetre or kilogram unless otherwise specified in these rules. (Rule 2.7.7)
3.2.3 The corners of sails shall be measured to the intersection point of the extension of the sides of the sail except in the case of a headboard where they shall be measured to the top edge of the headboard or as described. Refer to Figures 6 and 7.
3.2.4 Measurement dimensions may be provided from other rating certificates if they are consistent with the requirements of this system.
3.2.5 One Design Class ratings may be requested by a region or Class Association for a design that meets published One Design rules. The class must enforce these rules. Refer to Definition: "One Design"
3.2.6 The ISAF Equipment Rules of Sailing (ERS) apply to measurements except where specified otherwise in these rules. Changes to the ISAF ERS may not be adopted by the AMS or SMS.
3.2.7 RRS 50 applies to the setting and sheeting of sails unless altered in these rules.
3.2.8 RRS 50.4 does not apply. Refer to rule 3.7.1
3.2.9 Sails shall be measured according to ERS Part 3, Section H.5 unless specified otherwise in these rules.
3.2.10 Exotic materials used in sailcloth may be rated from time to time.
3.2.11 There are no crew weight or crew number limitations.
3.2.12 Transom width for designs without a transom shall be measured at a nominated distance determined by the YRSA Office taken from the Stern Point. Refer Figure 1 and Rule 3.8.
3.2.13 Unless noted otherwise on the certificate the Rating does not apply to vessels that utilise devices or procedures to move ballast. RRS 51 applies.
3.2.14 Unless noted otherwise on the certificate the Rating is based on the use of a mainsail, headsail, spinnaker, hull shape, ballast and overall design as broadly defined in these rules and the Yachting Australia Special Regulations, Part 1 of the RRS.
3.3 Boat Weighing Requirements
3.3.1 All boats must be weighed. When weighing, the water tanks must be empty and the bilges sponged out. Fuel in tanks may be estimated in litres from dip tubes or gauges. (Rule 2.7.7)
3.3.2 Outboard motors must also be weighed separately and must be carried on the transom or in a designated location ready for immediate deployment. An Inboard engine is to be fully installed.
3.3.3 One set of genoa and spinnaker sheets, guys and permanent control lines may be left on board when the vessel is weighed. Anything else not mandatory for Category 6 safety equipment must be removed. Bunk cushions, if always carried must be dry.
3.3.4 All fenders, warps, scullery gear, navigation gear, books, contents of drawers, tool kits, all sails, spare standing or running rigging, gas bottles, cooking and kitchen implements, food, clothing, bedding, spares, loose gear and crew may not be left on the boat. Refer to Appendix 1 for further details.
3.3.5 Batteries and all permanent fixtures must be installed in their normal position.
3.3.6 If rated to a class standard then the standard fitout must be presented for weighing.
3.3.7 The weight of the permitted items (Rules 3.3.1, 3.3.2, 3.3.3, 3.3.4) if these are weighed separately, may be added to the empty weight of the boat.
3.3.8 All Ballast, Moveable Ballast and Unweighed Items must be declared. (Rule 3.8)
3.3.9 Weighing procedures are included in Appendix 1
3.4 Hull, Rig and Appendages
3.4.1 The measurements to determine the length of the waterline plane (LWP) and the overhangs, where required are shown in Fig 2. These measurement are to be taken with the boat in the correct weight trim. Overhangs are to be measured from a plumb line hung from the LOA positions atÂ each end of the hull to the waterline intersection point using a floating rule.
3.4.2 All appendages must be declared. The YRSA Office may increase the draft to allow for the span of a wing keel.
3.4.3 Twin rudders are permitted.
3.4.4 Interior fitout is taken into account in determining a rating and must be declared.
3.4.5 Exotic materials with a specific gravity higher than lead may not be used as ballast in keels.
3.4.6 A Rig rating adjustment may be applied in the case of unusual, high tech or less efficient systems that are not already adequately rated in the standard system.
3.5.1 The following dimensions are to be measured (shown in Fig 1) for the largest headsail carried:
Luff Perpendicular LP
Half width HHW
Three quarter width HTW
Seven Eighth width HUW
Sail headboard HHB
Head Width HWH
Luff Length LL
Foot Offset HF0
3.5.2 Headsails may only be sheeted from a single point on the sail.
3.5.3 A headsail is any sail tacked down in front of the forward mast except a sail defined as a spinnaker. Refer to rule 3.7.1
3.5.4 RRS 50.3 is amended as follows:
Headsails no larger than the measured largest headsail may be attached to a spinnaker or whisker pole provided that a spinnaker is not set, STL is not exceeded and any whisker pole length does not exceed the J dimension.
3.5.5 Where a bowsprit is primarily used to attach a headsail tack the J dimension shall be measured to the tack attachment point on the bowsprit.
3.5.6 Furling headsails do not receive a rating allowance.
3.6.1 Sails are to be measured as shown in Fig.1 ,Fig. 6 and Figs 7a and 7 b. Refer also to Section 3.8.
3.6.2 The adoption of new shapes for the head of the mainsail may require the measurement of the Head Width Mainsail HWM dimension in place of the Headboard MHB.
3.6.3 For the measurement of square top mainsails refer to Figures 7a and 7b.
3.7.1 A spinnaker is a three cornered sail set forward of the foremost mast, where the half width (SHW) is greater than 75% of the foot dimension (SF) and which does not contain battens. Fig.1, Rule 3.2.7. All other sails tacked down forward of the mast are headsails.
3.7.2 Symmetric and asymmetric spinnakers are rated differently and the largest of each type must be measured by an approved Measurer. If an asymmetric and symmetric spinnaker are both carried then the largest of each type must be measured and the measurements submitted. Refer to Definition "Spinnaker Type".
3,7,3 A spinnaker may only be sheeted at a single point.
3.7.5 A spinnaker may not include a yard arm.
3.7.6 The STL dimension shall be taken from the forward face of the mast to the extremity of the longest spinnaker pole or to the extremity of any bowsprit to which the spinnaker is tacked or to any tack point on deck.
3.8 Abbreviations and Measurement Definitions
(Refer also to ISAF Equipment Rules of Sailing)
AMS Australian Measurement System
Beam The maximum horizontal width of the hull (and wings if any) as described in Fig. 7 excluding any fittings such as toe rail or rubbing strake.
Ballast Any item, material or substance built into, added or removed from the boat that is used for the purpose of changing its trim or stability.
Bands: Adopted in some locations for SMS. Bands are optional in AMS and must be used if multiple mainsails are to be measured. Painted on the boom and mast in contrasting colours to indicate the maximum effective P and E length permitted. Entered into the Input Form as P and E and noted on the form.
Moveable Ballast: Any item (including the keel, sails or provisions), material or substance that is moved during a race in order to change the trim or stability of the boat. Includes water ballast and canting keels.
BO Bow overhang. Measure the overhang of the bow at the water line from the forward end of the LWP to the forward end of the LOA. Use a plumb line off the bow and a floating ruler. To be measured in weighing trim.
DISP AMS weight measured in RRS Safety Category 6 racing trim or as otherwise specified for Sportsboats.
Draft The maximum depth of the vessel in measurement trim below the waterline.
Drive Saildrive, stern drive, in line (shaft)drive.
E The length taken along the boom to the inside edge of the band (Fig 1).
Es The length of the foot of the mainsail from the tack to the clew.
E-band The distance from the aft of the mast (bridge any gaps) to the inside edge of the band along the boom. Refer to ISAF, ERS.
ERS ISAF Equipment Rules of Sailing.
FL The forestay length taken from the deck at the attachment point to the mast set with the rig in its âbaseâ rake position for 10-15 knots of wind.
Leech Aft side of a sail.
Luff Forward side of a sail.
Hull Form: Some examples of hull forms are included in Fig 8. Photos should be attached to Input forms if possible.
HHB The largest headboard top width for the largest headsail. Measured fore and aft at right angles from the luff extension to the aft leech extension of the sail at the widest point of the headboard or head of the sail. Refer to rule 3.5.3. and Fig 6. Also refer to HWH and HWM below.
HHW Headsail half width is the shortest distance measured from the half leech point to the luff. Any reverse curve or hollows in the leech must be bridged.
Hiking Lines Flexible lines, replacing lifelines in sportsboats, approved by official class rules and which do not contravene the Notice of Race for the event.
Hiking Devices Trapeze, Wings, Hiking lines or any other device that extends the crew weight to windward of the gunwhale. To be noted on the Application form.
HFO Headsail Foot Offset: The maximum distance from the foot of the sail to a chord line taken from the clew to the tack measurement points and expressed as a percentage of the chord length. Fig. 8
HTW Headsail three quarter width is the shortest distance measured from the three quarter leech point to the luff. Any reverse curve or hollows in the leech must be bridged.
HUW Headsail seven eighth width is the shortest distance measured from the 7/8 leech point to the luff. Any reverse curve or hollows in the leech must be bridged.
HWH Replaces HHB on headsails with square tops or without a conventional headboard.
HWM Replaces MHB on mainsails without a conventional headboard or as shown in Fig.7. HWM must be greater than 0.75m.
Refer to MHB below.
J The foretriangle base measured from the foreside of the mast to the attachment point of the forestay to the deck or bowsprit. This dimension is parallel to the waterline and may need to be projected.
Keel Type: Determined with reference to the standard drawings in Fig.4. Photos should be attached to Input Forms if possible.
LOA The overall length of the hull from bow to transom. Exclude all fittings, rigging, bow sprit and pulpits. Do not included a transom hung rudder or rudder fittings. Do not include a transom scoop that artificially extends the LOA. Refer to definition of SC.
LL Measure the Jib Luff Length from the tack to the head along the luff using the intersection points of the sidelines if in doubt about the position of measurement points.
LP The shortest distance measured from the clew point at the intersection of the jib leech and foot lines to the outside of the luff including the luff tape.
LWP Calculate the length at the waterline by subtraction of the bow overhang and the subtraction of the stern overhang taken at the LOA measurement point, from the length overall (LOA). Refer to definition of LOA and Figure 3.To be measured in weighing trim.
M Mast dimension measured from the top of the boom to the base of the crane or to the base of the masthead turning block if no crane exists. Refer to Fig. 1. A measuring tape may be pulled up on the main halyard in order to take this measurement. (A retrieving line may be useful). Add the distance from the top end of the tape to the halyard attachment extremity of the shackle or to any stopping device on the halyard (ie a plastic ball).
MHB The mainsail headboard measurement is the measurement fore and aft at right angles from the luff of the mainsail to the leech of the sail or its extension at the widest point of the headboard. MHB may not exceed 0.75m. See Figure 6 and refer to HWM above.
MRO Measurement YRSA Office.
MHW Mainsail mid width measurement (measurement point is determined by folding the head of the sail to the clew and marking the leech at the fold point). Measure the girth from the leech fold point to the nearest point of the luff including any bolt rope.
MTW The mainsail three quarter (Â¾) width measurement point is obtained by folding the head of the sail to the mid leech point and marking the leech at the fold point. Measure the girth from the leech fold point to the nearest point of the luff including any bolt rope.
MUW The mainsail seven eighth width measurement point is obtained by folding the head of the sail to the three quarter
leech point and marking the leech at the fold point. Measure the girth from the leech fold point to the nearest point of the luff including any boltrope.
For square top mainsails the MUW measurement fold point may be located above the leech extension point used to measure HWM. In this case the MUW must be included as 0 (Zero) on the input form. Refer to Figures 7a and 7b. In this case MUW must be included as 0 (Zero) on the input form. Refer to Figures 7a and 7b.
One Design: A One Design class rating is based on the maximum sail, hull and rig dimensions and the minimum displacement permitted under the class rules.
P The length taken up the mast to the inside edge of the top band. (Fig 1).Refer to P-band below.
Ps The length of the luff of the mainsail from tack to head. Measure to the intersection points of the sidelines if in doubt about the position of the head and tack measurement points. If the tack is placed in a position that artificially shortens the Ps dimension then also measure Pext and add 50% of Pext to the measurement from head to tack to arrive at Ps.
P_band Used in place of Ps where mast bands are used. Indicates the extremities for the mainsail settings. Add 50% of Pext to P-band where applicable. This is shown as P on certificates.
Pext Pext is the extension of Ps to a position consistent with a right angle formed with the position of the clew and the extension of the tensioned bolt rope . This dimension only applies where Ps is artificially reduced by raising the location of the tack. See Figure 6.
RRS Yachting Australia Racing Rules of Sailing.
SC A transom scoop that artificially extends the LOA of the hull. Measure separate to LOA. Refer to Figure 3.
SF The spinnaker foot length of the largest spinnaker is the distance between the clew and tack points measured according to Figure 6.
SO AMS only. Stern overhang taken to the LOA measurement point and to include dimension Y (Fig 3).To be measured in weighing trim.
Spinnaker Type: If an asymmetric and symmetric spinnaker are both carried then the largest of each type must be measured and the measurements submitted. The measurement for the spinnaker pole, SPL and /or bowsprit, STL to be used with each spinnaker type is to be submitted with the spinnaker dimensions.
SPL When the largest spinnaker pole or whisker pole is attached to the mast and measured from the front face of the mast held horizontal along the centerline
of the boat to the end of the pole.
Square Top Mainsail: A square top mainsail is defined as a sail where HWM applies.
Stern The Stern Point for the measurement of TW is defined on vessels without a transom to be the aft intersection of the deck and the hull. Refer to Figure 1.
STL For bowsprits, measured to the extreme end of the pole or bowsprit including the end fittings, or to any other tack point on the deck. If there is any extension piece between the block and the tack point then tension the block forward and measure to the aft edge of the block snap shackle.
SHW The half width of the largest spinnaker carried is the distance measured between the mid luff and mid leech points from luff to leech.
SLE The length of the leech of the largest spinnaker measured along the edge of the sail from clew point to head.
SLU The length of the luff of the largest
spinnaker measured along the edge of the sail from clew point to head.
SMS Sportsboat Measurement System
TW The maximum width of the transom excluding any fittings such as a toe rail or rubbing strake. If no transom exits then this measurement is taken at a defined distance for that particular design forward from the Stern Point. Refer to Figure 1.
Unweighed: All additional items not weighed other than sails, running rigging, personal gear, reasonable quantities of provisions, cooking equipment and items specified in the RRS Special Regulations for the Race Safety Category and which are not part of the weighed Displacement (DISP) and are carried in a race. To be noted on the application form.
Wings Any extension to the beam of the boat, including flared topsides, incorporated into or added to the sides of the hull. To be included into the beam measurement of the boat and to be noted on the application form.
Y AMS only. Height above the water at the underside of the transom intersection point. Fig.3 AMS only.