Challenger Trimaran Design Rules 2006

1. The intention of these rules is to keep the main components of the Challenger to a single design so that, in hull form and rig plan, boats should be equal whilst racing.

2. Where used, the words “shall”, “should” or “must” are mandatory. The word “may” is advisory.

3. Any interpretations of these rules should be referred to the Chairman, or Senior Officer available, of the Challenger Class Association who shall, if required, consult with the Class Committee to provide a suitable answer.

4. Existing MK1, Aero-Rig and MK3 boats are excepted from the relevant rules regarding their different rigs, fittings and front cockpit arrangements, which are permitted for racing if used in their original design configuration.

5. Hulls

5.1. All hulls shall only be moulded by a builder authorised by RYA Sailability and/or the Challenger Class Association.

5.2. Challenger hull moulds are a one-design shape. Offsets and measurements shall not vary from those of the original 1979 design of Rod McAlpine Downey, except as modified by Reg White in 1991 and called MK2 or MK2a. All future hull moulds shall be to the same pattern and dimensions as the MK2a Challenger moulds in use in 2005 unless changed by the procedures outlined in 5.3.

5.3. New moulds may only be used after inspection and authorisation by a nominated representative of the Copyright holder, currently RYA Sailability, and the Challenger Class Association. Any design changes shall be agreed by a majority vote of the Class Association committee, which must be endorsed by the copyright holder.

5.4. All main hull deck moulds shall maintain the same general layout as the MK2a Challenger by seating a single helmsman in a forward-facing cockpit in the main hull. (Existing Mk3 and Aero-rig versions with front cockpits are allowed by exception) The cockpit shall have a double bottom to maintain emergency flotation, with water drainage from the cockpit through the centreboard case, such that the cockpit can be drained dry. The seating position must be capable of trimming the boat in the water with the helmsman in place. There must be a sealed mast box, in a suitable position for a rotating Una-rig, which does not allow water into the main hull. A hole may be drilled in the bottom of the mast box to restrict the height of water in the box and allow water to drain after sailing.

5.5. Inspection hatches may be cut into the decks as necessary and are recommended between the mast and cockpit and between the transom and cockpit. They must be of a design that is watertight when sailing.

5.6. There shall be a mast deck plate, maximum length 155mm, over the mast box with a hole cut to fit the mast collar, minimum distance 20mm from one fore-and-aft edge, to act as a deck-level bearing for the mast.

5.7. Adequate foam buoyancy shall be fitted in each hull, so that the boat will remain upright and above the water surface even when the hulls are breached or full of water. Extra internal buoyancy, such as bags etc. may be fitted.

6. Crossbeams

6.1. Crossbeams shall be of anodised aluminium to provide a maximum beam for the boat of 3.50 metres. Front beam 2 ½”(63.5mm), rear beam 3”(76.2mm), tube wall thickness 1/8” (3mm) +/- 1/16”(1.6mm) with plastic end caps. They shall be secured to the hulls by M10 stainless bolts screwing into phosphor bronze inserts built into the hulls, or similar arrangement.

7. Mast

7.1. The mast shall be provided by Needlespar, or such replacement supplier as approved by the Class Association and copyright holder. It shall be made from aluminium, unstayed with taper top, slotted to allow the kicker boom to pass through, with a domed plastic or aluminium foot to allow rotation. Maximum height 6400mm, maximum cross section within a rectangle 60mm x 75mm.

8. Boom

8.1. The boom shall be aluminium rectangular-section, provided by Needlespar or nominated replacement supplier, with flat aluminium kicker boom attached to the front and grooved on top to allow a movable clew-attachment device. Maximum length 2650mm from back of mast to end of boom. Maximum cross section 85mm x 37.5mm

9. Kicker/vang Boom

9.1. The Kicker Boom shall have shoulders protruding 20mm forward of the main boom aluminium section and the main section shall pass through the mast to a maximum 755mm protruding from the front wall.

9.2. A removable stopper shall be fastened into the kicker boom a maximum of 20mm from the front mast wall to prevent the boom from sliding back when in use.

9.3. The kicker/vang assembly shall be fastened to the front of the kicker boom and to a point on the mast which gives a total length of assembly of 2010 mm +/- 20mm. Additional blocks or fairleads may be positioned anywhere on the Kicker boom.

10. Rudder

10.1. The rudder blade may be manufactured from wood or GRP.

10.2. Pattern 1: - Shape must fit into a rectangle 820mm x 245mm. Maximum thickness 20mm. All edges may be bevelled. The trailing edge may have a sharp apex and the leading edge may be rounded. Leading and trailing edges should be straight and parallel.

10.3. Pattern 2: - Must conform to the dimensions of the Topper Blaze/Vibe rudder.

10.4. All rudders must be capable of being swivelled to the horizontal position by control lines accessible to the helmsman in the cockpit.

10.5. The rudder stock may be of any suitable pattern and must be fastened directly to the centreline of the transom by pintles and gudgeons or two gudgeons and a single suitable locking pin through both.

10.6. Control lines from the tiller shall be attached to a T-bar, which may be removable from the stock or may be permanently attached. If removable, it should be secured by a split pin or similar through the stock and bar. Control lines may be adjustable for tension.

11. Tiller

11.1. The tiller assembly shall be to a pattern endorsed by the Challenger Class Association and the copyright holder. It shall be mounted on the cockpit foredeck or the main crossbeam.

12. Centreboard

12.1. The centreboard shall be made of GRP and shall be to the dimensions of the pattern moulded by the approved builder in moulds approved by the copyright holder and/or the Class Association. Wooden centreboards to the same pattern supplied as original equipment in boats below number 200 are allowed by exception.

13. Controls and Fittings

13.1. All rig, centreboard and rudder controls can be of free design and may be fitted anywhere on the boat, particularly to take into account the limitations of various disabilities with the intention of equalising sailing performance between them.

13.2. Powered assistance by electric winches etc. is permitted to equalise disabilities, for any function other than additional propulsion.

14. Sail

14.1. All sails shall measure to the following dimensions:

· Luff – 5.38 metres; Foot – 2.41 metres;

· ¼ height – 2.003 metres; ½ height – 1.58 metres; ¾ height – 0.96 metres

· To find ½ height, fold head to clew and mark the leech at the fold.

· To find ¼ height, fold the foot up to the ½ height position and again mark

· To find ¾ height, fold head down to ½ height point on the leech and mark

· All measurements are the shortest distance from leech to luff.

14.2. Dacron sails shall have cloth weights as follows:

· Heavy panels along the leech – 275gsm.

· Light panels along the luff – 250gsm

14.3. Mylar sails shall have cloth weights as follows:

· Heavy panels along the leech – 250gsm.

· Light panels along the luff – 160gsm

14.4. All sails shall be supplied by Mouse Sails, who are the registered Official Challenger Class Sailmaker. Roger Lacey of Mouse Sails is registered as the current Class Measurer, until replaced by the Challenger Association committee. He shall measure and sign all sails, to confirm compliance with the above Class dimensions, before they are dispatched.

14. Total Sailing Weight

The weight of the Challenger, with rig, fittings and sail, shall be a minimum of 140 kilograms.