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Wednesday, 2 September 2015

Tricorn - An early all-GRP cruising dinghy

The Tricorn dinghy was designed by Illingworth and Primrose in 1962. Since theirs was one of the most famous names in offshore racing yacht design at the time, she came with some impressive pedigree. The design brief appears to have been to create a low maintenance dinghy, capable of serious open water passage-making, that would be better and faster than Ian Proctor's well proven and famous Wayfarer class.

Back then in the early 60s there were very few dinghies purpose-designed for construction in GRP. Almost certainly this was the first boat to be designed by Illingworth and Primrose for this type of construction, and at the time the Wayfarer would only have been available in plywood, so although Angus Primrose had certainly designed dinghies before, the Tricorn brief must have come as a considerable new challenge. His approach, in common with most other designers who were learning to work with this little known material, was to make the boat strong and not to spare on materials. When you examine the layup of a Tricorn, you'll notice a predominance of woven rovings throughout, and lots of reinforcement in areas where a contemporary wooden or plywood dinghy might have had a tendency to develop stress cracks or other weakness.

Very unusually for such an early fibreglass boat, there is almost no wood, except for the tiller, rudder, and some backing pads for deck fittings. This may have been a bit too avant-garde for the times, since boat enthusiasts in those days would have expected quite a lot of visible wood trim, coamings, decks, floorboards, benches, hatches, etc. The all plastic Tricorn might have been regarded as just too space-age and factory produced, and this perception, as well as its price and the narrowness of its marketing concept, may have seriously limited sales. Eventually only 37 were built.

Not that there was anything wrong with the performance of the Tricorn, nor its ability to shelter its crew of 2 adults, plus maybe a child, for overnight camping stops. Contemporary boat tests make it clear that Tricorn had the edge over the Wayfarer in both departments, although nowadays, after 50 years of Wayfarer class development, the Tricorn would probably struggle to keep up on some points.

Almost certainly, however, Tricorn would still show a Wayfarer a clean pair of heels to windward, since with her centreplate fully down she draws 1.6m (5ft 3in) to the Wayfarer's 1.17m (3ft 10in). She is also a few inches longer overall and carries around 1sqm more windward sail. Compared to the Wayfarer, Tricorn is noticeably less stable at rest, though she stiffens up when under way.

Tricorn's domed foredeck and short cabin roof enclose a cuddy with sitting space for 4 adults or sleeping space for 2 (in quarter berths extending under the cockpit side benches). There would be just enough space left over in camping mode for a child of up to about 7 years old to stretch out. There's a large watertight locker aft, and two capacious cockpit side lockers, probably not really totally watertight in the event of capsize, but which resist rain, spray, and even a fair amount of solid water landing in the cockpit.

4 years or so ago, I found and bought an old Tricorn. It was very scruffy, had a hole in the bottom, and lacked its original moulded forehatch cover as well as the original winch for lifting the centreplate. This 1963 example had at some time been used as a sailing school boat and was fitted with a horrible non-original rusty steel plate, weighing in at 50kg or more, double the original design spec. In addition, the mainsail had been reduced in area by cutting the foot off it to a depth of about 1m. These modifications must have made her extremely slow and dull to sail.

Salvo is now back in sailing order with a few minor changes to her original specification. I changed the overweight rusty centreplate to one that weighs about 20kg, about the same as the original design, but mine is home-made from a sandwich of steel, epoxy and plywood. I had to give up on finding an original plate lifting winch and fitted a simple tackle instead. I made a forehatch cover from plywood and clear polycarbonate, and lastly, I changed from a transom mainsheet track to centre sheeting for no better reason than I was scared the sheet might foul on my outboard motor and cause a capsize. The old roller reefing boom was replaced by one from a Fireball, to which I fixed some fittings for slab reefing.

I made a new rudder blade cut from the plywood centreboard from an old Miracle dinghy, but it snapped in half in a fearsome tiderace in Brittany, so I have gone back to the original which I might repropuce in aluminium plate.

There are still a lot of niggling problems to sort out. For instance the original self bailers let more water in to the watertight cockpit than they remove, so my feet are always wet. The in-mast jib halyard emerges from the mast foot in such a way that it is difficult to tension properly. I'm considering making it external from a point just below the spreaders so that I can swig it up tight. Most importantly, because of the total lack of rowlocks, a rowing thwart, and a stowage space long enough for decent oars, it's impossible to row the boat in the event of flat calm and engine failure. Emergency propulsion consists of a long paddle at the moment.

In spite of the age of the design, and these minor shortcomings, I like my Tricorn.  She is a fine, strong, and capable boat - with one hell of a pedigree!  

Salvo at La Semaine du Golfe du Morbihan, 2019

Tricorn Sailing Dinghy
Designed by Illingworth and Primrose, 1962
Built by Martin Goacher Ltd.

LOA:  16ft 6in (5m03)
LWL:  15ft (4m57)
Beam:  6ft 2in (1m87)
Draft:  9in (0m22) plate up, 5ft 3in (1m60) plate lowered.
Air draft:  24ft 6in (7m46)
Sail area:  139 sq ft (12.91sqm)
Weight in sailing trim: approx. 580lbs (263Kg)

Link: http://bursledonblog.blogspot.co.uk/2012/05/tricorn-dinghy.html