German Americas Cup Yacht under construction in Kiel

GER-89: High speed through high-tech

The official sail number is revealed. Not so the design. A network of designers, engineers and boat builders is presently working at a fast pace in order to finish the first German America’s Cup yacht. Being built at the shipyard Knierim-Yachtbau in Kiel, Germany, the about 26 meter long and four meter wide boat shall lead the United Internet Team Germany to its first success at the 32nd America’s Cup in Valencia, Spain in 2007. Latest technologies are employed to reach maximum speed on the water. The boat is expected to be launched in April, displaying the sail number GER-89 on its main sail to herald a new era in the young German strand in the history of the world’s oldest sports trophy.

“We are on schedule“, says United Internet Team Germany’s Technical Director Eberhard Magg from Kressbronn, “the yacht will be ready for testing in spring.” Until then, he and his team will be very busy. With the deck already finished, the carbon hull is presently being laminated at the shipyard on Kiel Canal.

Before this, the – hopefully fastest – hull shape had been chosen out of 70 different varieties, every single one of them designed by using complex computer calculations. The team of ten designers is headed by Axel Mohnhaupt (Berlin), and includes renowned designer Fietje Judel from Bremerhaven. ISKO, a Munich-based company delivered the computational fluid dynamics (CFD). The hull shape had been milled out of a block of foam by a giant five-axis milling machine with millimetre accuracy. The boat builders first laminated a carbon negative mould, in which they then laminated final hull.

“Using a female mould saves unnecessary weight on the hull by saving filler“, explains shipyard director Gunnar Knierim. “This is state of the art“, adds his partner Steffen Müller. After having applied several coats of pitch black carbon fibre in different thicknesses and varying directions, the hull is put into an oversized oven where the shell is “baked” in order to cure efficiently. Afterwards, the internal structure (bulkheads and keel structure) is added to ensure the necessary strength. Everything is as light as possible while providing maximal stiffness. This is the job of even, a Zurich-based company from Switzerland, whose work is usually related to Formula 1 motor sport.

Knierim keeps a staff of up to 22 workers for this job – building an AC yacht is handcraft. “They are all artists,” praises designer Mohnhaupt the thorough work of the international group of boat builders, whose goal it is to follow the design drawings as accurately as possible. And if there are no miscalculations, the German America’s Cup yacht can be expected to be really fast.

But yacht design would be way too easy if there were no complex concepts behind every single shape of keel, rudder, mast, sails and lots of other aspects. “We are still working on some details,” says Mohnhaupt, but by and large, the design of GER-89 is finished.

The requirements are provided by the America’s Cup Management in the 58-page Class Rule which only allows so-called Version 5 boats for the next Cup. The Class Rule’s design parameters are now stricter than they were for the 31st AC, making the boats more similar to each other. Yet the design is still one of the best kept secrets and the eleven challengers of the Swiss defender Alinghi will be anxious to keep their hands close to their chests.

Even though the given box is tight, most of the technical data is only roughly outlined. The AC yacht is allowed to weigh 24 tons and nine kilograms, with the nine kilograms only accounting for measuring tolerances. Depending on the final weight of the boat above the waterline, a lead bulb of approximately 20 tons is attached to the keel, which has a draft of 4.10 metres. The mast must weigh at least 750 kilograms and will loom about 33 metres into the sky.

The mast design is approved by Germanischer Lloyd (GL) in Hamburg, and the spar is produced at Formula Spars in Lymington, England. ”We will achieve a high technical standard,” Mohnhaupt promises, when nothing revolutionary could be expected anyway. It had been surprising to see the old AC yachts being altered to comply with the rules for Version 5, with their different shapes being so close in speed and performance at the preliminary Acts in 2005. However, even laymen will be able to differentiate the new GER-89 from the training boat GER-72 at first sight.

As soon as hull and rig (mast with all fittings) are finished, the main focus will be on sail design. Until then, everything is restricted to theoretical calculations. The first tests will then be used for further practical developments in order to find the optimum configuration. The sail area also has to meet rule requirements. The upwind sail area is roughly 320 square metres, of which 215 square metres are the mainsail. Downwind, the AC yacht will be pulled by a 510-square metre spinnaker.