SAN DIEGO - America's Cup designers want the lightest-possible boat winches and, ultimately, learn through on-water performance or failure. Some syndicates bought winches from suppliers Lewmar Marine Ltd. of Hampshire, England, and Harken Inc. of Pewaukee, Wis., on the basis of light weight at any price.
``Composite parts have worked well, and we had no winch problems'' in the most recent round of races, said John Marshall, PACT 95 president. PACT 95 pulled an overloaded winch out of the deck Jan. 14, had two winch drums fail Jan. 15 and lost the starboard primary winch Feb. 23.
``We broke quite a few things and had to beef up some metal components,'' Marshall said.
While rapidly easing sail lines, PACT 95 fused polyester-covered rope to filament-wound carbon fiber drums. The fix: Bond a heat-dissipating stainless steel sleeve to each winch drum.
Carbon fiber, weighing one-third to one-half of aluminum for a comparable part, is used now in winches along with aluminum, titanium and stainless steel.
Polyetheretherketone roller bearings eliminate a metal race and provide a ``huge weight savings,'' said Bill Ottemann, chief engineer for Harken winches.
Harken substituted carbon fiber for metal in PACT 95's primary winches, crank handles, winch grinder pedestals and winch connecting shafts, using epoxy to attach metal splines.
A New Zealand team decided otherwise.
``We've changed from carbon fiber to titanium shafts,'' said TAG Heuer Challenge Skipper Chris Dixon. ``The shear strength of some carbon fiber components was found to be insufficient.''
Lewmar, a division of Guilford, Conn.-based International Marine Holdings Group, supplies winches to TAG Heuer. Since 1992, Lewmar winches made ``significant gear-ratio gains,'' increasing line speed and sail control, said Jason White, North American aftermarket manager.
The Lewmar winch package on America3's new boat ``is about 20 percent lighter'' than the one on the winning 1992 boat, said Peter Wilson, technology operations director.
Lewmar's testing of winch 839 reached a load of 14,000 pounds before failure, Wilson said. The required load is 5,000 pounds.
Lewmar's bevel boxes of double-bias carbon fiber are ``much lighter'' than cast aluminum, Wilson said.
Team Dennis Conner is pleased.
``We had one problem related to how we interrelated a bonded bracket into the boat,'' said Bill Trenkle, operations manager, ``but we've had a huge improvement in weight and no sacrifice with performance. ''
Lewmar supplies winches to Conner and to oneAustralia.
OneAustralia experienced a winch problem prior to its catastrophic hull failure March 5.
``We'd already blown the main drive shaft of our port main primary winch,'' Skipper John Bertrand said, ``so we were [using the smaller] port runner winch.''