The Wivenhoe One Design Plans and Specification





KEEL Oak, depth or siding 1 1/2", width 4" amidships tapering to 3" at each end.
STEM Oak, moulded 2 1/2" at head, sided 3" aft side tapered to 1 3/4" on fore edge in way of forestay eye plate for a length of 7" down from top, tapered to 1/2" below in way of stem band.
APRON (To be solid) Oak, sided 5 3/4" at top to 4" at bottom, moulded to give a faying surface to the plank ends of not less than 2 1/". To be secured to stem with not less than three through fastenings.
FORE DEADWOOD (Optional) Oak 2" wide, 2.25" sided, riveted through stem and keel with five copper rivets, gauge 10.
HOG PIECE (Solid) English Elm, 5.5" wide, 0.375" thick, through fastened to keel with copper nails.
TRANSOM (Solid) Mahogany, in one piece, 1" finished thickness.
STERN KNEE Grown Oak 1" x 1", 2" sided, 4" throat, two copper rivets through transom and two through keel, gauge 10.
CENTREBOARD CASE Mahogany, 1" finished, fastened through keel with 4" brass screws, gauge 12, spaced 6" apart. Two grown oak knees at fore end, (one each side, 7"x7"x0.75")

Centred plate must be totally enclosed aft of forward edge of thwart. Forward edge of plate box must not be less than 11 1/2" above hog.

PLANKING In not less than 12 strakes a side. Top strakes Mahogany, Garboard strakes in Elm or Oak, remainder Silver Spruce, 3/8" thick.

A 1/8" radius is allowed on all exterior lands of the planks.

TIMBERS (Or as built) Ash or American Elm, 3/4" x 3/8", spaced 4" centre to centre and doubled for a distance of 3" abaft the mast beam to a length of 1 foot below deck, fastened through lands with copper nails, gauge 13, clenched with 3/8" roves and one nail through lands between timbers.
FLOORS Ash or American Elm, 0.75"x0.75", spaced 1 foot apart commencing 2 foot 6" forward of transom, 10 floors in all.
DECK BEAMS (Solid) Oregon Pine, 3/4 "x 1 1/2", three before mast and two aft of cockpit, half beams (seven each side) spaced 1 foot apart.
CARLINES Oregon Pine, 3/4" x 1 1/2"
MAST BEAM (Solid unfaired) Oak, 3"x2", with two knees on after side, 7 1/2 " x 7 1/2", 3/4" thick, 3" throat.
BREASTHOOK (Solid) Oak, 3/4", 6"x6". 3" throat.
QUARTER KNEES Oak, 7"x7", all riveted through skin.
SHELF Oregon Pine, 1.25"x0.75", gauge 12, copper nails through fastened in every alternate timber.

9mm Marine Ply to BS 1088.

COAMINGS (Shaped as plan) 0.375" Mahogany, 4.50 (3.50") high forward above deck, and 1.50" above deck at mast beam 1" aft with aft Oak knees 0.75" thick, 6"x6".
STRINGER UNDER THWARTS 0.375"x1" English Elm, fastened through every timber.
THWARTS Mahogany 9"x1", with 4 grown knees to each, 3/4" thick, 8" long, 3 1/2" throats, fastened through seat with two copper nails and skin with one rivet. The aft thwart is optional and also the side seats between thwarts.

The centre thwart must be permanently fixed to the structure of the plate box.

MOULDINGS Mahogany 3/4 "x 3/4", around coamings, around deck covering edge of matching, minimum 1"x0.50" Mahogany.
ROWLOCK CHOCKS (Optional) 10"x1.75" riveted through coamings.
MAST Silver Spruce, 3 1/4" square base solid, 3 1/4" diameter at band and hollow tapering to 2.375" at hounds and 2" at sheave hole, length 22 foot overall.
BOOM Silver Spruce, hollow, length 10 foot 6", diameter 2 1/4". Booms may be tapered to 1 3/4" diameter at ends if desired.

Grooved booms approved 1963 of any section rectangular but to the same basic dimensions.

CROSS TREES American Elm, clamped to mast 18" outside mast each side overall, 0.625" thick tapered from 2.625" at mast to 1" at end.
STANDING RIGGING Main shrouds and forestay single 0.50" circumference PSWR, topmast shrouds and topmast stay 0.375" ditto. Rigging screws or lanyards optional.

Stainless steel standing rigging now permitted.

MAST TRACK 0.625" channel section. Minimum numbers of track slides to be twelve, maximum fifteen.
SAILS Mainsail and two jibs as per blue print. Dimensions shown are fully stretched. Spinnaker to be to the size shown on sail plans, 12 feet x 8 feet Maximum. Maximum length of spinnaker boom 6 feet.

Spinnaker halliard block not to be above 18" from cross trees.

Only one spinnaker allowed in the boat at any one time.

Main sail material originally Egyptian Cotton with three batterns, maximum length as shown on the blue print, roach or round of leech not to exceed 9". Terylene approved in 1962.

CENTREBOARD Cast gunmetal or bronze, minimum weight 68 pounds and maximum weight 74 pounds.
RUDDER In accordance with the blue print, stock material Oak.

The rudder plate to be Manganese Bronze. The rudder plate to be 0.1875" thick.

New foil rudder approved 1992, stock: 1/2" plywood with 1/2" cheeks. Mahogany or laminated ply blade. Solid Ash or Oak Tiller as per new patterns.

SHROUD PLATES Brass or gunmetal, 9"x1"x0.1875" thick. The fore plates to be in line with the mast, aft plates 14" further aft. Or as built.
MAINSHEET HORSE 1/2" brass or as built but must be used.
ROLLER REEFING GEAR Can be adopted by any club if desired.
STEMBAND Half round brass, 1/2"
KEEL BANDS Half round brass, 1/2", at each edge of keel.
WEIGHT All-in weight approximately 600 lbs Minimum

These boats, having been designed as an inexpensive one-design class, the interests of the class as a whole can only be served by adhering to the specification set forth above in respect to the shape, size and materials of the hull, spars, centreboard, rudder, sails and standing rigging. Owners may subsequently add to the internal fittings and equipment of their boats, as they may desire, for example to vary the flooring, cleats etc,

A boat will not be disqualified for having the wrong material built in or for using a substitute when the original is broken provided that the boat speed is not GREATLY improved as a consequence.

Any development deemed by the WOD Association to be outside these rules and specification will be disqualified, there being a dispute procedure in place. The subsequent decision of the Chairman is binding.

Membership of the WOD Association will include the use of plans, specification and patterns as required.

Boats, the property of affiliated members, having been built to specification and measured by recognised measurers are eligible to race in the class and sail numbers will be allotted in rotation.

Copied from the copy dated 21.12.64 with subsequent amendments in bold added.

A meeting of the Association will be convened in order to officially adopt the above changes and members wishing to amend or add any amendments are to notify, in writing, the Chairman as soon as possible.