FOR THE
CANTERBURY J CLASS RC YACHT
GENERAL ~ HULL ~ MASTS ~ MAST FITTINGS ~ STANDING RIGGING ~ BOOMS ~ SAILS GENERAL ~ MAIN SAILS ~ JIBS ~ RUDDER ~ IDENTIFICATION MARKS
THE "J "CLASS
RESTRICTED DESIGN RADIO CONTROLLED MODEL YACHT
CLASS RULES (yet to be ratified)
1.1 The design is based on the full sized "J" class yacht Ranger with design changes to provide a model with good sailing abilities that is easily controlled by radio.
The rules serve to control the parameters of construction to allow for racing between boats of similar speed and characteristics. Material specifications and methods of construction are controlled with the intention of encouraging home building and keeping the class affordable to a large range of people.
It is intended that the rules of the class shall remain unchanged over time to ensure that all boats are able to retain a competitive position within the class and thus hold their value.
1.2 The class shall consist of a fibre glass hull from the Class Association's one official mould, a lead keel and trim weight from an approved mould, and rigs as per the sail plans with rigging that falls within the specifications.
[ADDENDUM - From the Annual General Meeting of October 30th 2004 -
General Business 5: - Bow Bumpers - Following on from the Minutes it was passed that the Class Rules be amended as follows:-
"That the Class Rules be added to, in order to show the fitting of a Bow Bumper on the Canterbury J Class be made mandatory. Such a bumper to be a minimum of ten millimetres in thickness; not be included in the overall length; and be subject to the measurer's approval." - Moved - Peter Vincent and Seconded - Mike Hefford - passed.
We noted that while we had no control over unmeasured boats, we should still make the fitting of bumpers a strong recommendation to other J owners.]
2.1 The hull is a one piece moulding of glass reinforced polyester resin produced in the official mould. No fibres or cloth other than glass shall be used as reinforcement of any resins used in the completion of the hull or fittings.
2.2 Dimensions of the hull
Maximum overall length: 1220mm
Beam; at quarter length: 145 -150mm
at half length: 215 -220mm
at three quarter length: 185 -190mm
2.3 Lead weights as per the Class Associations official moulds, or others approved by the Association shall be used. The keel shall be bolted to the bottom of the hull, in a position so as to lie fairly onto the keel stub with the minimum of filling required to provide a smooth underwater section. Such a position shall normally be so that any discrepancy between the keel moulding and the keel stub shall be equaled at either end. The trim weight shall be bolted to the front keel bolt on the interior of the hull by drilling a hole, central on the weight and at a position approximately 40mm from the wider end of the weight. The weight shall be positioned so that the tapered section of the weight faces forward and the weight lies flat on the timber floor. No materials other than lead shall be used for ballast.
The weight of the complete boat with mast, booms, rigging, sails, and radio gear , including batteries, of a type and size normally used in radio controlled yachts, shall not be less than 6.500 kg when carrying the " A" rig as per the measurement diagrams.
Any additional ballast required to be fitted to bring the weight up to the minimum weight as required shall be fitted to the underside of the deck immediately above the centre of buoyancy so as to not affect the fore and aft trim.
Note that if the boat is constructed in the spirit of the Class Association, with commonly used materials, and with no attempt being made to exploit the rules, the requirement to add ballast will not arise.
2.4 The RUDDER shall be as per the official pattern with the rudder post included in the area for measurement purposes. The length of the after face of the keel, should be between 205 and 210mm. No fairing between the top of the rudder and the hull or between the keel and the leading edge of the rudder is permitted.
3) RIG
3.1 A rig is defined as a mast, a mainsail and its boom, a jib with its boom, all with permitted fittings and rigging.
3.2 The principal material for all spars shall be aluminium alloy or wood. No composite materials such as carbon fibre or kevlar shall be used. Aluminium alloy may be anodised.
(a) When in racing trim masts shall comply with the measurement diagram forming part of the class rules.
(b) Masts may be stepped on or through the deck.
( c ) Mast stubs are permitted.
(d) Measurement bands shall be displayed on the mast, in a colour that contrasts with the mast, at the top and bottom of the mainsail. The distance apart shall not exceed measurement "A" on the measurement diagram. An additional band shall be marked to reflect the maximum allowable height above the deck for the jib attachment. This band will be positioned not less than measurement "I' below the top mainsail band.
For the purposes of measurements the distances being measured shall be between the measurement bands. Measurement bands shall be between 3- 10mm in width.
( e ) Masts shall be of constant circular section without grooves for internal sail tracks. Maximum diameter shall be 12.7mm (1/2") and tapered spars are excluded from the class.
(f) The mast will be stepped at a point 490 -540mm from the bow with the optimum being 530mm.
(g) For the purposes of measurement the deck level shall be measured from a straight line between the gunwales at a distance of 530mm from the bow.
Each mast may have :
(a) One wind vane.
(b) One back stay crane to extend the fixing position of the backstay to the mast head beyond the allowed roach of the mainsail.
(c) Attachments for jib stay or halyard and shrouds.
(d) One pair of spreaders and their attachments.
(e) Attachments for the mainsail luff, head, and tack.
(f) Mast strut or ram and attachments.
(g) Check stays and their attachments are allowed only in conjunction with a mast stub and should be attached only to provide support for the stub when other rigging is being changed.
(i) A gooseneck fitting and its attachments. No ball raced fittings are permitted.
(j) A kicking strap and its attachments. This may be combined with the gooseneck fitting.
(k) Mast base and deck track fitting on deck stepped masts.
4.1 Masts shall be supported by:
( a) Jib stay and/or jib halyard. Forestays of a rigid type are not permitted.
(b) One pair of shrouds with optional inner lower stays. Spreaders are permitted but are restricted to one pair on each mast.
( c ) One backstay which may be split into a two part bridle no higher than 300mm above the deck to allow for tensioning adjustment if desired.
5.1.1 Construction :
Booms shall be of aluminium alloy or wood with a constant circular section not exceeding 12.7mm (1/2") in diameter. Internal sail tracks are not permitted.
5.1.2 Mainboom fittings:
Each mainboom may have:
(a) Attachments for tack, sheet, and clew.
(b) Kicking strap.
(c) A gooseneck fitting of any type or style, excluding ballraced fittings
5.1.3 Jib boom fittings:
Each jib boom may have:
(a) Attachments for jib stay, tack, sheet, clew, and topping lift.
(b) A Boom swivel.
(c) Counterweight which must not extend beyond the bow when measured on the centreline.
Sail sizes and dimensions are restricted to the three rigs are shown
in the Class Measurement Diagram.
6.1.1 All sails shall be single ply material made and measured in accordance with the current ISAF Sail Measurement Rules. No laminated cloths or laminated films are permitted.
6.1.2 Sails shall comply with the measurements on the Class measurement diagram forming part of these classrules.
6.1.3 During measurement sail battens need not be removed and sails may remain attached to the spars.
6.1.4 The same sail material and weight shall be used throughout the body of each sail. -
6.1.5 Seams, including reinforcements and tablings, shall not exceed 15mm in width.
6.1.6 Corner reinforcements shall not exceed 125mm in any direction when measured from the corner measurement point.
6.1.7 Telltales may be fitted to mainsails and to jibs.
6.1.8 Cringles or eyes not exceeding 10mm in diameter may be used at attachment points.
6.2.1 Each mainsail shall be made of a maximum of four panels joined by seams which shall not be closer than 150mm to a corner .
6.2.2 Any method of attachment of sails to the mast is permitted with the exception of an internal grooved sail track.
6.2.3 The leech or foot of the sail shall not be convex between measurement points.
6.2.4 There shall be three battens supporting the leach. Battens should be fixed within 3mm of each measurement point on the sail with the top batten not exceeding 75mm in length. Other battens shall not exceed 100mm in length.
6.2.5 No part of the mainsail shall extend beyond the lower edge of the upper mast measurement band or the upper edge of the lower mast measurement band.
6.3.1 Each jib shall be made of a maximum of three panels joined by seams that are no closer than 100mm to a corner measurement point.
6.3.2 The luff tabling may envelope the jib stay and a luff tube may be fitted provided that no support against forestay sag is gained by the fitting of a such a tube.
6.3.3 The jib leach shall not extend outside a straight line drawn from the clew measurement point to a point 20mm aft from the upper measurement point.
6.3.4 There may be a maximum of two battens fitted to support the leach of the jib.
7.1.1 Each mainsail shall carry
the class identification marks in accordance with the ISAF regulations.
7.1.2 The class insignia is the letter J as per the diagram
7.1.3 Class numbers shall be displayed on both mainsail and jib in accordance with the ISAF regulations for model yachts.
7.1.4 (a) The sail number shall be the boats registration number.
(b) There shall be a space in front of the sail numbers for a prefix "1 ". The use of this prefix shall be prescribed by the Race committee in the event of a clash of sail numbers.
(c) Where there remains a clash of sail numbers the Race committee shall prescribe that sail numbers be amended to other numbers until the clash is resolved.
( d) The size and spacing of identification marks shall be as follows:
NATIONAL LETTERS ~ Height 60mm ~ Width excluding "I" and "T" 40 -45mm ~ Thickness 8 -12mm ~ Space between adjacent letters 13 - 18mm (Class letters as per 7.1.2)
DIGITS ~ height 100 -110mm ~ Width 60 -73mm ~ Thickness 12 -18mm ~ Space between adjacent digits 20 - 25mm
Vertical space between marks on opposite 60 -100 sides of the sail. space between sail numbers and other marks 100 minimum. Both sides of sails shall carry identification marks. They shall be placed at different heights, those on the starboard side being uppermost. Headsails shall carry sail numbers. They shall be below an imaginary line projecting at right angles to the leech from the half leech point. Mainsails shall carry sail numbers which shall be above an imaginary line projecting at right angles to the luff from a point on the luff one third of the luff length from the tack. If this is not possible then numbers should be as high as possible. National letters, if required, shall be carried below this line. Mainsails shall carry the class insignia above the sail numbers.
Where the sail is too small to achieve the spacing requirements the spacing may be decreased as necessary to an absolute minimum of 13mm in the following order:
1. Between sail insignia on opposite sides. 2. Between the starboard side number and the port side insignia.
3. Between numbers on opposite sides. 4. Between letters on opposite sides.
5. Between the starboard side letters and port side numbers.
Where the sail is still too small to use the specified size digits and letters even with the minimum spacing of 13mm smaller national letters and digits may be used as necessary.