Swept away by a tidal wave

By ROBIN BAILEY

Attracting attention at its Viaduct Basin berth, and raising eyebrows even higher when it's on the water, is Tsunami, a radical Greg Young-designed yacht destined for the tourist market.

Built by Vaudrey Miller Yachts at Henderson, it was commissioned by New Zealand-based Marine Tourism Holdings for day-sail operations within their new Cruise Whitsundays business in Queensland. The company says it will prove to be the fastest bridge-deck catamaran of its type in the world.

The design brief called for captivating styling, thrilling sailing experiences, large passenger loads and safe operation with a minimum sailing crew.

As intended, Tsunami attracts interest and radiates the promise of great speed, even at rest. The design draws people in; towards the curvaceous central house, arcing fore-beam, lightly loaded bows and glistening black prod. It is not just Tsunami's strong colour and 25.9m (85ft) by 11.5m (37.7ft) size that takes the eye.

The prominent fore-beam, clean bows and high wing-deck are fundamental elements of Young's design philosophy - keep the structure stiff and strong to retain rig tension and superior sail shape, and minimise weight and drag so boat speed builds quickly and is maintained even when the bows are buried in a seaway.

Even in light winds Tsunami seldom sails at less than ten knots and, in optimum trade winds with a moderate number of passengers aboard, guests can expect an exciting ride to 25 knots and well beyond.

MTH selected Vaudrey Miller Yachts to realise Young's concepts because of their proven composite construction, custom engineering and project management skills.

High Modulus engineer, Nina Heatley, says Tsunami posed challenges in terms of weight, the length of spans and performance levels sought. "We drew on established cruising catamaran data, computer modelling and elements of PlayStation to develop the composite structure. There was some cross-over from PlayStation to Tsunami."

Mould costs and construction times were minimised by building the wing-deck and each side of both hulls in temporary female frames, a tactic that also allowed Vaudrey Miller to optimise labour distribution across many jobs.

The exterior composite skin includes a layer of Kevlar to increase impact resistance when sailing at speed and abrasion resistance when Tsunami is beached daily at Whitehaven beach for guests to have lunch, snorkel and swim. With the stern anchor deployed and the bows kissing the beach, guests can disembark via a carbon fibre ramp that is raised and lowered using a line to the forward anchor windlass. When stowed for sailing, the passenger ramp aligns with the prod and locks in under the front beam.

In addition to hospitality services, the fit-out included specifying and engineering the failsafe hydraulic systems that allow Tsunami to be sailed with up to 100 passengers and only two sailing crew. The mainsheet and staysail are hydraulically operated from each helm station using toggle switches that interface with a microprocessor and a hydraulic power-pack. The boom-vang, mainsail outhaul, mast rotation, dagger boards and primary winches are also operated by the hydraulics.

Tsunami has a very clean layout and, apart from the vang and a few hydraulic lines from the boom to the mast, the hydraulic sailing systems are not obvious. The multiple mainsheet rams are carried in the carbon fibre boom and the genoa/staysail sheet ram is fitted under the deck within the starboard hull.

The winches, which hoist the sails and sheet the Code Zero headsail flown from the prod in light airs, provide a manual mainsheet and staysail sheeting option should a circuit in their respective hydraulic systems fail. And if sailing is not an option, Tsunami's twin 75hp Yanmar diesels provide a 10 knot cruising speed when fully loaded (100 passengers, provisioning for the day, 1800 litres of fuel, 1600 litres of water and 250 litres of waste). Top speed under power is 15 knots in light trim.

Sea trials were conducted to ascertain whether running backstays and check stays were required and they were fitted after the photographs were taken. The aerial of Tsunami sailing under full main and staysail were taken with the catamaran logging an effortless 23-24 knots.

Tsunami will be sailed from Auckland to Mackay on the tropical Australian coast, about 100 miles south of where it will be based at Airlie Beach inside the Whitsunday Islands. With the capability of logging 300-400 mile days in delivery trim, the 1800-mile Tasman crossing via Lord Howe Island should take five to six days.

SPECIFICATIONS

Length overall 26.00m 85.3ft

Beam overall 11.50m 37.7ft

Minimum draft 1.50m 4.9ft

Height off water 33.50m 109.9ft

Displacement lightship 24 tonnes 52,910lb

Displacement full load 30 tonnes 66,138lb

Sail area:

Genoa 110 m 1184 ft

Mainsail 190 m 2045 ft

Code Zero 270 m 2906 ft

Engines: 2 x 75 hp Yanmar 4JH3TE

Mast and boom: Matrix, black lacquered carbon fibre