Lengthen a GRP tender
Edward Sutton builds a dinghy extension
Sawing an old dinghy in two to make it more practical
Wasting so much potential sailing time inflating our rubber dinghy, I realised our family needed a larger dinghy to transport us out to our boat on a swinging mooring in Portsmouth Harbour.
We already had an old, moulded fibreglass dinghy, but now too small and rather flimsy, it was stored behind our house and hadn’t been used for years.
I had experience with mixing polyester resin and laminating fibreglass from previously assembling a fibreglass kit boat, so decided to lengthen and strengthen this old dinghy to become our new tender.
The plan was to cut it in half and build in an extension, making it half a metre longer.
I realised that a simple addition in the middle of the hull to increase its length by 20in would spoil either the lines of the gunwale or the curve of the bottom. The only way to avoid this seemed to make a cut round the line of maximum beam and maximum draught.
This curve resembled the side of a jigsaw piece but I plucked up the nerve and cut the dinghy into two halves.
To aid adhesion the cut edges were power-sanded to a 6in taper on both sides. I then used old aluminium litho printing plates (normally scrapped by printers) to act as formers to laminate against and these were bent to the desired curve, waxed to prevent resin adhesion and taped under the area to be created.
Once port and starboard insides of the hull were laminated on the inside, the whole assembly was inverted so the bottom of the hull could be completed.
After sanding, the new area blended in perfectly and could only be detected before painting by its comparative transparency compared with the old hull material. Additional strengthening came from new keel and bilge timbering and new thwart stringers.
The extended dinghy has now given very long service, survived numerous bashes, heavy groundings, lift-outs and launches.