True-Clutch uses small electric servo motors to control its activation. ‘We have to think harder about ways of conserving power,’ Biddick says, ‘and the ever-creeping saltwater is a challenge with everything we do.’ ‘For every Cup cycle we download the rule, try to imagine how the boats will develop and put together a general package of the sort of things they might need,’ says Wiss. True- Clutch was part of that package. The new Single True-Clutch is a refinement of the original but it's built entirely in carbon fibre (even the spring, which is has a lower modulus than the other components). It can handle more than 1,000Nm of torque (the maximum output of an eight-strong team of world class grinders), yet the whole assembly weighs just 1kg. ‘People will probably ask why we didn’t do this before,’ Wiss says. ‘The answer is because the technology wasn’t there to make it small and light enough.’ The Single True-Clutch allows seamless, full-power shifting in and out of individual functions and is adequate for most if not all of the manual-powered hydraulic functions on board. For functions involving a winch, such as hoisting code sails or gybing, a more complex Double True- Clutch has also been developed and delivered to the teams. This enables the grinders to shift throughout the sequence of winch gears without having to stop or change cadence, and it’s integrated with an overdrive gearbox that allows the output to accelerate and return to normal, on demand. ‘It’s a new concept for the AC75s that we developed with a mindset that came out of that cycling world,’ Biddick says.
On an AC75 it’s the trimmers and flight controller who decide where the power goes, using electronic push-buttons mounted at their
Above: ʻyou can measure its effective- ness by the smiles on the grindersʼ facesʼ. Until now, teams of grinders on every large, manually powered
racing yacht have had to pause while changing gear. Now they can just keep going – and keep the hydraulic oil constantly moving. Right, top: True-Clutch can be fitted on the base of a pedestal, as shown, or in various other places throughout the system. Middle: the single True- Clutch is
used for fully hydraulic functions. Lower: the double True- Clutch with an overdrive box is used with a winch for hoisting and gybing
stations and linked back to the servo motors on the Single and Double True-Clutch assemblies. The reaction time of this electronic relay is much faster than any mechanical linkage could achieve, Wiss explains. Wiss and Biddick are both tight- lipped about the actual numerical efficiency gains for a team of grinders using pedestals with True-Clutch over an equivalent team using a regular dog clutch system – that’s the sort of data rival manufacturers would love to get their hands on – but while it’s clearly substantial, the functional benefits of True-Clutch are probably more important. ‘You can measure that by the smiles on the grinders’ faces,’ Biddick says with a grin. ‘You no longer have two guys fighting each other or trying to shake the handles slightly out of sync. One key factor is that the accumulator charges stay up. You don’t have the problem of ‘I can’t trim the mainsheet while the other guys are bleeding off something else.’ It’s a testament to Harken’s rock- solid resolve to be at the absolute forefront of sailing technology that the company puts so much effort into developing niche solutions like True- Clutch for America’s Cup teams and other grand prix campaigns even when there isn’t a strong commercial motivation for doing to. ‘The Harken brothers have always encouraged us to do that,’ Wiss explains. ‘Sometimes the technology transfers into commercially viable products for the broader sailing market. However, a lot of the time we develop something that works very well for the team but then that’s the end of it. And that’s alright.’
True-Clutch is undoubtedly relevant for any racing yacht, with or without foils, that has a team of grinders on board. ‘For now it’s available in standard AC75 size,’ Wiss says. ‘How we expand the range depends on what the market
requires.’ There are clear benefits for boats like TP52s and Maxi72s if class rules allow the technology, which remains to be seen. Will grinders remain part of grand prix sailing? ‘I hope so and I think they will because it’s an important part of the athletic side of sailing,’ Wiss says. ‘It’s interesting that they’ve disallowed the bicycle technology that was used in AC35 because of the disassociation with sailing – and it was Team New Zealand that wrote the no-bike rule despite having used it to win the Cup. We were already preparing a bicycle grinder solution and have put it to one side (for now!).’
www.harkenatthefront.com q SEAHORSE 67
INEOS TEAM UK/CAMERON GREGORY
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