The New Stitch & Glue Senior

The following narrative is the method that Alison and I used in the construction of a prototype stitch and glue ‘Senior’. We are sure that others will have better ideas, methods and construction techniques and we look forward to hearing of these. My local B&Q Warehouse was moving to new premises and I was able to pick up 2 lathe benches for £5.00 each, armed with these and 2 lengths of 100mm x 50mm timbers and a 2.4m x 1.2m sheet of plywood, I had the basis of a large work bench.

We started by marking out the plywood sheets with the templates supplied by Tony Dench. These were then cut out with a jig saw until we had a large pile of pieces. Each piece was marked and the 6mm holes required to ‘Stitch’ them together were drilled, (we purchased 200mm x 6mm cable ties and constructed a template to repeat drill the holes). As the standard sheet size was only 2.4 meters long each panel was made up of at least 2 pieces, over lapping pieces were cut to allow butt jointing, which were then stuck together with the Epoxy resin. The Cabin Bulkhead was cut out in 4 pieces, 2 of these were now glued to form 1 panel as shown later.

Panels cut and laid out like a giant air-fix kit

It's like a giant Air-fix kit!

All the pieces were then laid out in the order required so that when assembled, they will form the hull. The basic shape began to take place, we started stitching together the 2 bottom sections, the transom was fitted and the cabin bulkhead lower section, which form the hull angle. The 1st chine panels were ‘Stitched’ on followed by the third. The shape evolves as each panel is ‘stitched’ into place, and the basic hull shape is formed.

The Forward bulkhead and the 2nd and 3rd inner transom bulkheads were fitted to the hull forcing the panels into the hull’s familiar shape.

The Epoxy and flour was mixed as directed by Pete Johnson and applied to all inner joints and connections leaving the cable ties in position. The hull was turned over and all cable ties cut of with a sharp chisel, then all outer joints were filled with the Epoxy⁄flour mix. When cured the entire exterior of the hull was sanded down, any holes refilled and sanded and then coated with 300kg woven roving glass fibre and Epoxy resin.

The hull starting to take shape

Starting to take shape

The hull, now very sturdy, was turned over and work on the cabin was started, the roof beams were constructed by laminating 3 layers of 9mm plywood together with Epoxy resin and wood flour mix clamped onto an arched former. This was achieved by drawing the arch of the cabin roof on to a piece of timber 250mm wide and 50mm thick. A 50mm x 25mm batten was cut through the 50mm width to within 10mm of the face at 20mm centres to enable the batten to follow a light curve. This was then glued and screwed to the timber board along the scribed curve line to create the former for laminating the roof beams. 9mm plywood off cuts were squared and stripped into 50mm wide random strips. The middle layer of the three layers was drilled at 15mm centres with a 6mm drill bit, the three layers were laminated together with Epoxy resin and wood flour mix clamped to the former until cured. The cabin shape was formed with 25mm x 50mm battens laid stern to bow, with the laminated roof beams fitted port to starboard.

Fitting the deck

Fitting the deck

The cabin sides were then fitted to the formed shape with 9mm plywood cut to shape and fixed with Epoxy resin and wood flour fillet. The whole roof was covered over with 9mm plywood and secured with Epoxy resin and wood flour fillet the same.

The front storage locker, which is formed between the front bulkhead and bow section was solid filled with polystyrene foam to act as a buoyancy tank after 2 hard wood blocks were Epoxy resined into position, one in order to give the towing eye a solid bearing when fitted later and the other at deck level to receive another fitting later.

It had been confirmed that the designer of the ‘Senior’ Mr. Kenneth Gibbs, was not concerned if his design was altered by home builders and readily gave his permission when asked. It was under this aura of permission that in order to simplify the construction and to enable this design to readily convert to the ‘Stitch and Glue’ method, we altered the design and gave it a more modern look. This entailed loosing the front deck and extending the cabin forward to the bow, and by widening the cabin and loosing the side decks. The result has created a stronger hull and is easy on the eye, which we hope will help sales.

The cockpit sides were added but doubled up to form a strong triangle shape, and as a bonus it makes the seating area more comfortable.

The decision was made early in the build to install a well for the out board motor with a buoyancy tank either side instead of lockers. This was created by the construction of a box shape made out of 18mm plywood glued into position in the stern and coated with woven roving and Epoxy resin. The resulting pockets either side were filled with polystyrene foam for buoyancy, and a hard wood block fitted to either side to receive the various fittings to be fitted later, and all covered over with 9mm plywood. The area over the engine well was doubled up and glued to ensure that, when cured and an area was cut out it retained its curved shape, this area is to be used as an access hatch to the outboard motor.

The cabin, cockpit and cabin bulkhead were sanded down and then coated with 300kg woven roving glass fibre and Epoxy resin and once cured the hull was turned over and the hull coated with 300kg woven roving and Epoxy resin to match the hull.

We decided to install a keel and hog to help spread the stresses which will be imposed to the hull via the mast. In our case we have obtained a mast, boom and a suit of new sails from a ‘Ballerina’ which are slightly larger than those intended for a ‘Senior’, so we felt that a solid keel and hog was the way forward. This consists of a 100mm x 50mm timber shaped to follow the hull and then glued into place and sheathed in 300kg woven roving glass fibre and Epoxy resin. All the internal joints were then taped and Epoxy coated for strength, and the entire internals Epoxy coated.

The cockpit floor and seats were then cut and installed. All joints were taped and coated with Epoxy resin in several layers. The resulting hull at this point is very strong, solid and extremely light. I am able to move her around on my own. The overriding opinion at this point is one of success and I will have no concerns launching and sailing this craft.

The mast support post is constructed using a piece of chromed 50mm copper pipe solid filled with Epoxy resin with galvanised spreader plates top and bottom, all secured into position with tape and epoxy resin.

Coating the hull and keels

Coating the hull and keels

The boat was turned over and a template of the hull was taken and used to construct the a Keel box shaped as on the drawings, this was then filled will 160lb of lead ingots as per the drawings and 2 no stainless steel bolts installed in a pre arranged position to match 2 holes drilled through the hull. The keel box was then filled with Epoxy resin to secure the whole item as a whole. The hull was then sanded and the keel box when cured was upended and glued to the hull with Epoxy resin and the nuts and washers tightened on the inside, and then the whole keel was covered in 300kg woven roving glass fibre and Epoxy resin and run over the hull by 75mm to hopefully ensure that the parts stay as one unit.

The 2 bilge keels were constructed with 9mm ply and 50mm x 25mm battens to form a hollow box, these were then shaped to follow the hull and glued into position, when righted supporting battens were laid into the hull at right angles and screw fixed into the bilge keels below. The battens were then sheathed with 300kg woven roving glass fibre and Epoxy resin and again run over and down the hull by 75mm to give additional strength. Once cured the hull was again sanded and then painted.

The rudderstock was constructed from 3 pieces of 12mm plywood shaped as drawings and glued together. The blade was shaped to a design as produced by Rodney Leaper when he improved the design and sailing characteristics of his senior ‘Pau Amma’. The rudder arm was shaped from a solid piece of mahogany and fits onto the rudder stock with an aluminium locating sheath. The cabin doors were cut from 3 pieces of 9mm plywood and fitted in to hardwood runnels as standard design, with weather strips fitted onto the bottom edges and all coated with Epoxy resin. The hatch was built by obtaining the same curve as the main roof and laminating beams in the same manner, the main frame is constructed with mahogany hard wood with 6mm plywood covering and UVPV plastic runners, screw fixed onto two timber battens fitted to the main roof, the roof will be secured with a padlock and hasp fitted to the rear of the hatch, thanks here goes to Tony Dench as it is by this method that ‘Fly Catcher’ is locked up.

The new YM Senior's body shell

The new Senior's body shell

The hull was then turned over to lay up for the winter, this was achieved on my own with plenty of polystyrene and rope, I do not know what she weighs but I am able to handle her quite safely and easily on my own.

Due to the bad weather last year this is as far as the build has reached due to the construction taking place in our rear garden, therefore it is essential that prospective builders construct under cover to increase the time available to complete the build. (Note the little problem we have with our dinghy in the foreground)

David & Alison Seymour-Jones
WW “Cherani II”

Note: This article first appeared in the Spring 2008 issue of the members Bulletin. We hope to have an article about the completion of the project to follow shortly. The boat was exhibited at the June 2009 Beale Park Boat Show.