CLASS MEASUREMENTS AND RESTRICTIONS
INSTRUCTIONS FOR MEASURING
THE MG14 & MG14B DINGHY
The duties of the approved Club Measurers are to measure all boats and equipment presented to them, to accurately record the measurements on the Class Measurement Form and to forward the completed form to the Association Measurer for approval.
The following instructions are meant for individual elected measurers and have been divided into four (4) sections:-
2. CENTREBOARD AND RUDDER
SECTION 2.1 HULL MEASUREMENT AND WEIGHING
Hull material used and hull construction should be inspected. Any boat that is found to be structurally unsound should be rejected.
In most boats that are to be measured it will suffice to estimate the waterline and drop perpendiculars for and aft of the boat upon that line. However, should there be a borderline measurement, the boat with crew and rigging should be floated in still water to establish the waterline. The crew should have a combined weight of approximately 140kg and should be positioned as for sailing to windward.
A spinnaker pole for an asymmetric spinnaker, or a support tube, wire or bracket for a spinnaker pole, which is attached to, protrudes from or forms part of the hull is not to be included in the overall length measurement, provided that it is wholly located at least 200 mm above the bottom of the stem of the hull. Support struts or brackets which serve to increase the waterline length are not permitted. A wire or rope may run from the pole and attach to the hull at or below the waterline without infringing this rule.
To assist in the measurement of beam, a caliper should be made as below:-
The hull should be turned upside down and the beam measurement checked 2.5m from the bow with the 200mm caliper arms set on the 1.22m mark. While the boat is upside down apply the taut tape rule 1:7.
Reset the caliper to 1.6 m and check that the beam at the widest part is not less than the caliper setting.
The minimum beam 200mm above the bottom of the keel controls the stability. It is measured to the outside of the skin of normal shapes but to the inside of any bilge keels or unnatural protuberances in the skin shape.
An unnatural protuberance is a bulge or extension of the hull skin outward from its natural form which:
(i) in the vertical plane does not form a fair curve or which forms a fair curve whose radius is less than 150mm.
(ii) in the horizontal plane does not form a fair curve over a distance of 1000mm on either side of the minimum beam measurement point.
Examples of the application of this definition are shown below:
Turn the hull upright, set the caliper to the 1.83m mark and apply the caliper to the hull with both the hull and the caliper held in the horizontal position. The hull should pass through the caliper.
Determine the depth using two parallel straight edges 2.0m long as illustrated below:-
Subtract distance A from distance C to obtain minimum depth B.
Apply the caliper to the hull using the 660mm arms and a straight edge. The hull, excluding all fittings and the mast step and pin, must pass through the 660mm gap between the caliper and the straight edge.
Ensure that any horizontal projections outside the normal extremities of the hull, with the exception of a spinnaker pole or support tube, wire or bracket for a spinnaker pole, comply with the rule and will collapse or bend on impact.
Apply the taut tape if not already applied when checking Rule 1:3.
Check to see that requirements are met
Should there be any doubt about buoyancy the volume should be measured by constructing and integrating a curve of areas, and this volume should exceed 0.45 cubic metres. A flotation test with full rig and crew should also be carried out when in doubt, as the main factor is the boat's ability to remain afloat and be sailed on after a capsize in heavy weather.
The hull shall be weighed while suspended from a single point and the weight of the sling deducted. Weighing both ends separately is not allowed. The Measurer shall be present at the weighing. When being weighed the hull shall be dry and everything removable shall be removed. This includes everything shackled on (such as pulleys, etc.) but not permanently fixed (such as rudder pintles).
If in the opinion of the Measurer, fittings or components that are not essential and are so loosely fitted that they could be removed for racing, shall be removed for weighing. If something normally removable, such as a rudder, is fixed “permanently”, e.g. by having the pintles welded with the apparent intent or effect of outwitting this rule, the Measurer should demand that it be removed for weighing, or be included in the length of the hull.
A hull must weigh not less than 64kg when it is raced. If it is weighed at the end of a season and ballast removed, it may be under weight and therefore illegal in the following spring due to drying out.
SECTION 2.2 CENTREBOARDS AND RUDDERS
Both centreboard and rudder should be examined to ensure that no increase of thickness exists. Measurers must use their discretion and minor variations to say 1.5mm overlooked as this rule is meant to stop the use of lead bulb upon the end of the board and not to catch the minor constructional variations in a centreboard or rudder.
Provision must exist for the tiller to be securely fixed to the rudder and for the rudder to be fixed to the hull so that neither can become unshipped during a capsize. Centreboard and rudder blade restraints must ensure that the centreboard and rudder remain entered in their respective cases during a capsize.
SECTION 2.3 SPARS
A 100mm internal diameter ring should be applied to spars to ensure they will pass through it.
Masts shall be either completely sealed to prevent the entry of water when capsized, or be filled with sufficient foam so that the mast will float, or have drain holes within 300 mm of the base of the mast capable of emptying a mast full of water within one minute. If there is any doubt a flotation or drainage test must be conducted.
For MG14: Check that the painted band is clearly marked and in the correct position relative to the deck (or bottom of the keel), and that the spinnaker halyard exit point is at least 800 mm below the bottom of the painted band.
For MG14B: Check that the mast height does not exceed 5.65m above the deck or 6.31m above the keel. Check that the spinnaker halyard exit point is not more than 5.1m above the deck or 5.76m above the keel.
A spinnaker pole for an asymmetric spinnaker, whether attached to the hull or otherwise, and when fully extended if applicable, must not project more than 1.4m from the bow of the hull. Such a pole must project approximately parallel to the centreline of the hull, and be fixed in the lateral direction, so that the tack of the spinnaker, when hoisted, is in line with a forward projection of the centreline of the hull. Spinnaker poles which can be set at a variable angle to the centreline of the hull are permissible only for setting of double luff spinnakers of maximum area 7.5 square metres.
No sail other than a spinnaker may be set beyond the bow of the hull from a spinnaker pole or its supports.
SECTION 2.4 SAILS
Sails shall be measured as described below. When measurement of sail area is specified, the Measurer shall use a method which measures surface area as distinct from projected area. The Association or Club Measurer shall sign each sail measured and shall mark thereon the sail area or perimeter measurement and the date of measurement.
The following instructions shall be closely followed:-
(1) Short cuts which save time but give less accurate results are not to be used (e.g. measuring the roach of the spinnaker or mainsail leech in one part where there is a large roach).
(2) All measurements are overall (e.g. to the outside of boltropes).
(3) Sails shall be measured off the spars and laid on a flat surface with the corners tied to suitable pegs.
(4) The mainsail luff shall be pulled taut with a tension of 10kg, which must be measured by a spring balance. If 10kg does not pull out most of the wrinkles along the luff more tension should be applied to give about the freedom from wrinkles which would be set in a fresh breeze. This is particularly necessary in the case of elastic boltropes. The head and tack shall then be tied to pegs leaving the tension in the luffrope.
(5) After the luff is tensioned, tension shall be applied to the clew by a cord leading directly away from a point on the luff 600mm from the tack, and the clew pegged leaving the tension in. This angle of pull puts a suitable tension in the leech as well.
(6) The luff and leech roaches shall either be held flat and free from wrinkles by inserting and tensioning the battens, or by pulling them out by hand and holding them by weights around the edges.
(7) The straight line measurements shown on the Class Measuring Form as A B C shall be delineated by tying a string tightly around nails inserted in the flat surface at the corners of the sail. In the case of cut off tacks and clews, the nails shall be inserted at the intersections of the projections of the luff and foot or leech and foot respectively.
A nail is inserted where the roach of the leech is at a maximum, (c) and string used to define E and F.
(8) The straight lines A B C D E F shall be measured from the nails. The areas of the triangles are given by 1/2 CD and 1/2 Cc respectively.
(9) The areas of luff, foot and leech roaches of normal shape and fair curve are computed by multiplying the length by two-thirds of the maximum offset, i.e. 2/3 Aa, 2/3 Bb, 2/3 Ee, etc. The foot roach shall be pulled out by hand if necessary to make the sail lay flat while the foot roach is measured.
(10) In the case of leeches which are not fair curves, e.g. peaked at the batten pockets, measurements shall be made to a fair curve of as nearly as possible the same area, i.e. passing slightly inside the peaks and outside the dips.
(11) If any roach is abnormal in shape, it shall be divided into triangles and/or rectangles as necessary to reduce the curved remainder to such proportions that the 2/3 length times offset rule adequately represents it. The details shall be entered if necessary on the back of the Measurement Form.
(12) In the case of cut off tacks and clews, the measurements shown on the Measurement Form as JK and LM shall be made and the omitted area subtracted from the sail area (i.e. recorded as a negative area component).
(13) In the case of double sails, when the two sides set separately, e.g. in double-luffed and pocket luff mainsails, both sides shall be measured and the total area counted.
(14) Jibs shall have their luff-wires tensioned as in (4). The clew shall be pulled about on the line bisecting the angle, with a tension of 5kg. If a Jib has adjustable luff tension, it shall be set to about the tension that would be set in a fresh breeze.
(15) String and nails are used to delineate the dimensions A B C as in (7) - the area of the triangle being 1/2 AD.
(16) Roaches are measured as in (9). In the case of hollow-cut sides, e.g. the leech (c), the area of the hollow is subtracted. The edges shall be pulled out by hand if necessary to make the sail lay flat while the roaches are measured.
(17) The area of double luff spinnakers shall be measured. Normal double luff, full spinnakers shall be folded in half. All areas should be calculated and the total area thus obtained doubled. The spinnaker when doubled shall be measured by the same methods as measuring the mainsail, except luff tension is only to be sufficient to remove most wrinkles from the luff and not 10kg except as below. Spinnakers with stretch luff should have the luff tensioned to 10kg or such pressure as is required to eliminate most wrinkles from the luff.
Should a flat spinnaker be presented for measurement it shall be measured flat and not doubled as above.
The foot of the spinnaker shall be pulled out by hand the same as clew tensioning in the mainsail. However, it should not be nailed but weighted to avoid damage to sail.
Spinnakers with stretch luff should have the luff tensioned to 10kg or such pressure as is required to eliminate most wrinkles from the luff.
(18) The perimeter length of asymmetric spinnakers shall be measured. The perimeter length is the sum of the lengths of the luff, leach and foot of the spinnaker. The luff, leach and foot shall be pulled taut for measurement, using a tension sufficient to eliminate most wrinkles. If the edge of the sail when pulled taut does not form a straight line, then the length along the curve must be measured.
(19) All measurements shall be made to the nearest millimetre. All area components shall be calculated to the nearest 0.001 square metre, counting 0.0005 as 0.001. All area components of an individual sail shall be totalled.
For spinnakers which are folded in half for measurement, the sum of the measured area components shall be doubled to determine the total area of the sail.
The total area of the sail shall then be rounded to the nearest 0.1 square metre, counting 0.05 as 0.1 (e.g., 6.749 to be rounded to 6.7, and 6.750 or 6.751 to be rounded to 6.8).
For the measurement of an asymmetric spinnaker, the luff, leach and foot length measurements, each to the nearest mm (0.001 metre), shall be added. The total perimeter measurement shall not be rounded.
For MG14: A mainsail and jib combination shall be rejected if the sum of the individual areas, each rounded to the nearest 0.1 square metre, exceeds 9.3 square metres.
For MG14B: A mainsail and jib combination shall be rejected if the sum of the individual areas, each rounded to the nearest 0.1 square metre, exceeds 10.5 square metres.
A jib shall be rejected if the area, after rounding to the nearest 0.1 square metre, is less than 1.4 square metres.
A double luff spinnaker shall be rejected if the area, after rounding to the nearest 0.1 square metre, exceeds 7.5 square metres.
For MG14: An asymmetric spinnaker shall be rejected if the sum of the lengths of the luff, leach and foot exceeds 14 metres.
For MG14B: An asymmetric spinnaker shall be rejected if the sum of the lengths of the luff, leach and foot exceeds 15.4 metres.
SECTION 2.5 ADDENDA
Check that the Safety Requirements of Rule 23 are met.
It is not possible to define every detail of the craft and thus any aspect deemed to be "not within the spirit of the rules" should be vetoed by the Measurer and the Association.
PROCEDURE IF BOAT IS SOLD
If boat is sold the new owner should forward this certificate to the association Registrar for re-registration:
Date of sale................................................................................................
Name of new owner.......................................................................................
New owner’s address......................................................................................
New name of boat.........................................................................................