AUSTRALIAN MULTIHULL DESIGNER Lock Crowther had appeal in Auckland with some Kraken 33 and 40 racing trimaran designs plus his racer/cruiser 40 foot catamarans being built here. Local multihull designers like Young (still interested despite early bad press), Ron Given and Malcolm Tennant had gained recognition few larger cruising catamarans. Given designed his own 36 foot lightweight racing catamaran Tigress in 1971, an open wing deck design like an enlarged Paper Tiger; it looked extreme and observers were impatient to see it line Given, Tennant had drawn larger designs but his examples also took time to build; multihull sailors invariably had little money and usually built their own yachts. Tennant had earlier built a few Australian B2 Class Stingray
Ron Given sailing his big Paper Tiger design Tigress at speed
Early Tennant Great Barrier Express design Excalibur
catamarans and tried unsuccessfully to get the class established here; then he designedcruising 36 foot catamaran named Vorpal Blade – but the owners took a decade to construct the boat. In 1972 he published his ideas on a 9.8 metre high performance wing masted catamaran he named Bamboo Bomber which had flared and stepped hull topside shapes with blister cabins fore and aft of the central cockpits; the boat looked a bit weird and spacecraft-like and nothing came from it. However in late 1972 I asked him to redraw the concept, clean up the lines by discarding the stepped cross section hull shapes and the result was an attractive and very modern (for those days) racing design – two examples of which began construction soon afterwards. Both yachts Supplejack and Superbird were launched in 1977 and were built in tensioned ply like large versions of the (then) Olympic class Tornado. Both wing masts ended up heavier than intended and made the light platforms pitch in some sloppy seaways and light winds – but given sufficient wind power to drive through waves, both yachts were very fast. Continuing loosely to the Bamboo Bomber theme he had first shown in Sea Spray, Tennant drew a clean looking, aft cockpit, blister cabin 8.5 meter racing/cruising catamaran named Great Barrier Express - which Tennant said was inspired by a Hawaiian beach cat developed Mickey Munoz. Compared to the second version of Bamboo Bomber, Great Barrier Express had more rocker in hull underwater profile (for easier tacking) and sloping transom hung rudders which could be lifted, whereas Bamboo Bomber rudders were fixed down and under hung. The latter rudders also sloped and had skegs – retrospectively bad mistakes - as too was the
Jim Young’s Bladon Racer trimaran - opposite: original Great Barrier Express
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sloping GBE rudder design – which tended to lift the sterns and push down the bows when sharp helm movement was made - later versions had vertical rudders to counter that problem. The original Great Barrier Express built and owned by Richard Pilkington was launched in early 1977 beating the Bamboo Bombers into the water. The cat had sensational speed and quickly became known as a giant killer; it was also instantly popular and went into production at Pilkington’s boatyard.
An early 32 foot trimaran Atria was designed by Jim Young for Dooley Wilson and launched in 1964.
This yacht had classical sheer in the main hull and because of this low freeboard amidships, placed the beams too close to the water surface, an early multihull design mistake, for the beams slowed the boat when driving through waves – a common problem with trimarans at that time. Wilson raced Atria in Tauranga for some years and then sailed it to Wellington where it was sold. Then in the mid 1970’s Young designed Wilson a 40 foot open wing deck trimaran named Bladon Racer; called a sketch for it was neither ketch nor schooner because both masts and mainsails were the same height and carried the same sail area in two roached, fully battened mainsails. “This was a low sail plan which kept the centre of effort down and reduced the tipping moment,” said Young. Although Young drew water ballast to be carried in the windward float to provide extra power, this was not fitted by Wilson. In the clever drawing, tanks which were linked to the centre board cases, could fill or empty to produce either buoyancy or lever arm weight.
Wing mast on Tennant designed Bamboo Bomber Supplejack
The original group of Given, Tennant and Fay had broken up by the early 1970’s; Given and Fay, who had collaborated on the Paper Tiger had split over disagreements with the design when it went into production which culminated in a court case. Then Tennant’s Great Barrier Express and Given’s Gulf Tiger competed for the quite lucrative fast cruising/racing catamaran market – and earlier friendship quickly evaporated. The Great Barrier Express hull was based closely on tensioned ply Bamboo Bomber and was round bilged while Given’s Gulf Tiger continued his Paper Tiger theme with hard chined hull cross sections. The GBE was more
performance oriented with the elliptical shaped cross section hulls having less wetted surface area than the flat sided, chined Given design. The after sections of Gulf Tiger were almost flat like a planing hull dinghy. The two also differed in rig design; Given aiming his Gulf Tiger to the average sailor by keeping the rig simple with a non-rotating mast and similar (although spreaders were much wider) to bendy, fractional setups of New Zealand dinghies – while Tennant drew a rotating mast and a high aspect ratio B Class catamaran-type rig for his design, making it higher performance and requiring some extra skills to handle. Given supporters were adamant that large spinnaker carrying Gulf Tiger would be the faster yacht – but were proven wrong.
Many club members considered open wing deck, lightly constructed multihulls outrageous and that these designs were nothing more than overblown day sailers with afterthought accommodation – which was correct. Duncan Stuart, who owned Kraken 40 Krisis, cracked, “If you close your eyes when on Supplejack’s deck and step onto the tramploline, you can’t tell any difference.”
With the success of the Great Barrier Express design Tennant was pressured by people with a non-surfer-type philosophy into making a larger hull design with more accommodation. So Tennant drew the Turrissimo version which was more inflated in hull crossection, higher wooded and slightly longer than the GBE. After the sleek lines and minimalist earlier surfer inspired boat, Turrissimo appeared gross to some eyes but Tennant had listened well – if people thought accommodation more sensible than balanced aesthetics, then he was going to give it to them – and fat Turrissimo turned out to be a faster sailer than its appearance belied.