PROJECT WINDRIGGER - June 1998 installment

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Construction of the hull - I made a fibreglass mould from a half-length strip-planked plug (photos 4 & 5) and used it to produce two half-length hulls which were ultimately glassed together - pre-aligned using a 5mw laser. A noseblock mould is bolted to the hull-mould allowing the possibility of building hulls with other bow/stern shapes. The hull mould splits along its fore-and-aft centreline and at the midship cross-section. This allows the option of lengthening the hull by adding a cylinderical-hull section to the centre of the mould. A cambered-deck of 600 mm radius was produced via a separate deck mould. The deck is fastened to the hull by screws so that it can be removed to facilitate modifications and manufacture proa/tri/catamaran versions.

The hull laminate - 2 layers of 600gsm biaxial fibreglass with an epoxy binder on a polyester gelcoat. The low-viscosity polyester gelcoat recommended by the materials supplier did not produce adequate depth of colour so I had to apply an external finishing paint coat. I would appreciate any advice on a solution to this problem. Adequate laminate stiffness was achieved by 19mm square Pacific Maple stringers spaced at 100mm centres and transverse bulkheads of 6mm plywood. I am very impressed by the ease of layup of the biaxial fibreglass and its lightweight of 1.8 to 2 Kg/sqm.

Photo 4 shows strip-planking the plug. My first experience with strip-planking which I found it to be very easy.

Photo 5 shows strip-planking the deck of the plug. Note that the lower part of the hull has been filled and sanded and noseblock added. Prior to this the strips were faired and covered with one layer of fibreglass/epoxy cloth to arrest shrinkage of the timber. I have included the plug photos to show that this hull could be striplanked in stead of fibreglassed. I could supply the fibreglassed noseblocks which would simplify this process.

I have enclosed other photos covering various features of Windrigger and which are described in the following with reference to the photo numbers:

6 - Note the spade rudder and tiller, and yellow dagger-board, all in the down-position.

7 - The spade rudder in the up-position. In the down-position the square-section rudder shaft is lowered and engaged into a corresponding square key-hole in the fin tube. The fin is retained by a cord which passes up through the rudder shaft to a jamb cleat on the tiller.

8 - Details of the stubmast arrangement for supporting the sailboard rigs as shown in photo 1. Photo 8 shows the sailboard mast, mast bottom socket and upper quickclip fittings, developed to support most types of sailboard sailrigs. This arrangement provides access for experimentation, to a very large number of sailboard sails which are superior to yacht sails and much cheaper. Previously I used a stubmast located inside the sail luff-sock with the lower-end of the sailboard mast supported inside it - like a Laser mast. Although this is aerodynamically superior only a few sailboard sails have luff-socks big enough to accommodate the required 60 mm diameter stub mast and this relatively-stiff stubmast does not bend to match the cut of sailboard sail and thus spoils the shape of the sail.

9 - Close-up of the stubmast-quickclip fitting. Not shown is a strut which a ties the sailboard boom to the stubmast so that it rotates with the boom.

10 - Detail of the attachment between the cross beams and the tubular outrigger. The points of attachment are bolt fastenings through wood-beams inside the tube. This crossbeam is the one used with the dory outrigger and Windrigger MK I.

11 - Cross beam attachment to the bridgedeck. This was not intended to be the best design - it was the quickest way to get to sea-trialling MK 2 hull.

12 - Rigged for trailering. Note the end caps on the tubular outrigger. These are epoxy/fibreglass mouldings - it took me 2 months to make its plug and fibreglass mould.

I hope this detailed information will help the very few that question yacht design and try to improve on it.

Sailing this present craft has reminded me that I am a pretty ancient mariner and that logically I must concentrate on developing the catamaran version. But there is an elegance about sailing it as flying proa that I find it very exciting and technically more perfect than other sailing craft.

Regards, Ian Smith