BOAT RACING ASSOCIATION "A" CLASS ONE-DESIGN DINGHY SPECIFICATION
GENERAL
Each boat to be carefully built in strict accordance with the drawings and this specification, and the greatest care must be taken to ensure that all boats are as nearly alike as possible in every respect. Minor deviations from standard may be permitted, at the discretion of the Council of the Association, but all boats built for the same club's classes must be alike. In no case will any deviation from the design be permitted as regards model or weight. If alternative materials be allowed, the finished weight of each boat must not be less than that of the standard. Notwithstanding any error in or omission from the drawings and specification, each boat shall be built, equipped and finished complete in every respect and so as to be fit for use as a 'useful yacht's centreboard dinghy'.
Unless otherwise mentioned, all scantlings given are finished sizes.
During construction, each boat shall be open to inspection by any persons appointed by the Council of the Association, and such person shall be permitted to take any measurements or other particulars to check the accuracy of the work. Each boat shall be built on moulds made from the full size drawings provided, and the planking must fit such moulds properly and fairly throughout. When completed, and before formal delivery is made, each boat must pass the inspection of the person appointed by the Council of the Association.
DIMENSIONS
Length overall 12' (3.7m)
Beam 4'8" (1.4m)
Depth amidships 1'8½" (0.5m)
Sail Area 100 sq.ft. (9.3sq.m)
KEEL
To be of clear rock elm, or of pitch pine for fresh water.
Siding to be of 2" (50mm) amidships and in way of slot, tapered to 1¾" (44mm) forward and 1½" (38mm) aft. Moulding to be in accordance with drawing, tapered from 7" (178mm) aft to 1¾" (44mm) forward.
Hog to be of rock elm or pitch pine, 4" x ¾" (109 x 19mm) amidships, tapered same as keel; to be fixed by brass scews, 2" No 12 (50mm x 4.8mm) spaced about 4" (102mm).
STEM
To be of English oak crook 1¾" (44mm) side, scarphed to keel and clenched up with three No 6 (5mm) copper nails, or the equivalent. To be rebated as usual for planking and the stem head to be finished as per detail.
STERNPOST AND KNEE
To be of English oak. The 1¼" (32mm) post to be let into the hog and the 7/8 knee (22mm) to be clenched and dead fastened with copper nails.
TRANSOM
To be of English elm, mahogony or teak ¾"(19mm) thick, screwed to the sternpost. A sculling notch to be cut as usual.
CENTREBOARD CASE
The slot for plate to be left ½"(13mm) in the clear. The constuction of case to be as per detail drawing, with sides of kauri pine or Oregon pine ¾"(19mm) thick, stanchions of oak or teak, capping of kauri pine, Oregon pine, mahogony or teak. The workmanship to be specially careful to ensure freedom from leakage. The plate pivot to be a 3/8"(10mm) metal pin, with a 5/8" (16mm) bush on same; rivetted in place with washers each side.
PLANKING
To be of selected and well seasoned clean white spruce, free from knots and shakes, clench laid 5/16" (8mm) finished thickness. 12 strakes each side, 5/8" (16mm) lap, all bevel taken off lower strake - except towrads ends, and lands not to be rounded-off. The garboard and sheer strakes may be of mahogony or other hard wood if desired by owners. Two land fastenings, No 14 (2mm) copper nails, roved, to be put between each pair of timbers, in addition to the usual timber nail.
TIMBERS
To be of clean live rock elm, steam bent, 5/8" (16mm) sided by ½"(13mm) moulded, spaced 7" (178mm) centre to centre along keel line. Face of timbers to be slightly rounded off. Timbers to run across keel in one length from gunwhale to gunwhale where possible. The garboard to be wedged under timbers, where necessary, with elm wedges.
FLOORS
To be of English oak 5/8" (16mm) sided, moulded to drawings, and spaced as shown. To be joggled down to planking, and fixed by a dead nail in each strake, with a clenched nail in each floor tip.
MAST STEP
To be of oak, teak, or elm, fitted out to skin and to stem, clenched through skin and screwed down to stem.
GUNWHALE
To be of clean rock elm 1¼" x 1" (32 x 25mm), tapered to ¾" (19mm) fore and adt. Timber heads to be joggled into gunwhales and clench fastened through each.
RISERS
An elm riser 1¼" x 3/8" (32 x 10mm), beaded on edges, to be fitted, below seats, and a similar one around outer edge of gratings. To be of clenched through each timber.
THWARTS
Two rowing thwarts to be fitted as shown, 7½" x ¾" (190mm x 19mm) with a pair of knees each end. Mast thwart to be 8" x 1" (203mm x 25mm) with lodging and hanging knees. Stern benches ¾" (19mm) thick, as per plan, to be fitted with thwartship bearer, 2" x ¾" (50mm x 19mm), and pair of stanchions to support same. All thwarts and benches to be of Oregan, pitch or kauri pine, or mahogany, or teak.
BREASTHOOK, ETC
Breasthook to be worked from a 1" (25mm) oak crook, nicely rounded on upper face to crop.
Quarter knees of oak ¾"(19mm) thick.
Thwart knees of oak ¾" (19mm) thick.
All knees to be grown crooks and to be free from sap and shakes.
PLATFORMS
Bow platforms to be of white spruce 3/8" (10mm) thick, ledged up. As shown on plan, main platforms to be battern gratings, made up with tapered spruce laths ½" (13mm) thick and 2¾" (70mm) wide amidships.
SUNDRIES
The usual stretcher blocks and bars to be fitted for stroke and bow thwarts, in elm, ash or teak.
Rowlock chocks to be fitted as usual.
Elm rubbing wales to be worked from 7/8" x 7/8" (22mm x 22mm) and bilge pieces from ¼" x ¼" (19mm x 19mm), 6' (1.8m) long.
FASTENINGS
To be of copper, brass or yellow metal throughout.
CENTREBOARD
To be of ¼" (6mm) mild steel plate, trimmed to dimension of detail drawing, with exposed edges sharpened back ½" (13mm). To be galvanised and cleaned off after dipping to give a smooth surface. The plate to be lifted by a ½" (13mm) single block attached to forward sling bolt, with a purchase consisting of two 2¼" (57mm) single blocks and 1" (25mm) manilla fall. The standing block to shackle to an eye-plate screwed to side of case and the fall to belay on a cleat at aft end of case.
RUDDER
To be of English elm, mahogony or teak, 7/8" (22mm) thick in the blade and well tapered-off towards the edges. The head to have a pair of cheeks ¾" (19mm) thick, well clenched up. A mortice to be cut for tiller, and a tiller of ash or rock elm to be provided, tapered from 1½" x 1' (38mm x 25mm) and 3'(0.9m) long, with handle end neatly rounded up. The rudder hangings to be of an approved pattern, in galvanised iron or polished gunmetal, and properly fitted.
FITTINGS
Stemband to be of half-round, ½" x 3/16" (13mm x 5mm) galvanised iron or copper, with ornamental head to fix to breasthook. A hole to be made through stem head just below band to take the shackle of halyard lead block.
Keelband to be of galvanised iron or copper 3/8" x ¼" (16mm x 6mm) 12" (305mm) total length.
Ringbolts of galvanised iron or gunmetal in stem and stern posts, 3/8" (10mm) shanks to rivet.
Davit slings to be fitted as shown in drawings with 7/16" (11mm) shank eyebolts rivitted to plate washers let into underside of keel. Chains to be 3/16" (5mm) with lon end links of 5/16" (8mm), all galvanised. Brass plates to be fitted on stern seat and mast thwart, that on the latter to take the mast also.
Mainsheet horse to be fitted to quarter-knees, as per detail drawing, to be made of 7/16" (11mm)rod, galvanised iron or Muntz's metal, with stop and shoulder collars welded or sweated , and thread and nut for fixing each end.
Shroud plates of galvanised iron or polished gunmetal, 6" (152mm) long under eye, to be fixed by screwing to timbers next aft of mast.
Cleats of approved pattern, in wood, galvanised iron, or metal, to be screwed each size of centreboard case for halyard and plate purchase.
Belaying pins of galvanised iron, greenheart, or gunmetal (two in number) to be fitted to mast thwart for tack, etc.
Rowlocks, one pair with four sockets to be fitted in galvanised iron or gunmetal, of approved pattern.
SPARS
To be of clean white or silver spruce, made and fitted as per detail drawings.
To be varnished three coats.
SAIL
Of union silk, as per plan, with stocking cover to take sail and spars.
Cover to be of waterproof or dressed canvas. The class number of boat to be marked on sail as required.
RIGGING
Shrouds, one each side, to be of 3/8" (10mm) circumference plough steel wire rope, with eyes to drop over masthead, and fitted with thimbles and hambro line lanyards at lower ends.
Halyard of 1¼" (32mm) manilla, single part, with whipped ends, and a 2¼" (57mm) block shackled to stem for lead. Tack of 1" (25mm) manilla, spliced around end of boom (with thimble seized in splice) and set up to sling chain eye on mast thwart.
Mainsheet of 1" (25mm) white cotton rope, with three 2¼" (57mm) rope stropped blocks as shown in the drawings.
Strops, lacing etc. as may be necessary.
FINISH
The whole of each boat, inside and out, to be varnished four coats best yacht varnish (or, if desired by the owner, the bottom to be painted three coats and finished with anti-fouling composition or enamel externally, and to be painted three coats internally). The name or number to be written in gold leaf and shaded on the transom or as may be required.
GEAR
One pair suitable or spoon bladed sculls.
Manilla painter 3 fathoms x 1¾" (5.5m x 44mm) circ)
Manilla start line 2 fathoms x 1½" (3.7m x 38mm) circ)
6' (1.8m) spruce boathook staff with galvaised iron or gunmetal shoe.
8" (203mm) galvanised bailer.
FINALLY
The whole, as specified, to be of the best quality as regards materials and workmanship, and each boat to be delivered complete in every respect after trial afloat under sail.
EXTRA GEAR (optional)
Waterproof canvas boat cover, made to fit properly and lace on over boat and spars.
Reproduced from  Classic Boat Magazine