Technology
Faster, lighter AND more reliable
Most of us take traveller cars and tracks for granted but the extreme sail trimming and roll stability requirements of AC75s and AC40s required Harken to redevelop its hardware for a whole new performance level
Balancing a monohull with no keel on a pair of foils that are offset from the yacht’s centreline has been one of the biggest challenges for high- performance yacht design in recent years. Understandably, in achieving this the foils themselves have attracted plenty of attention, particularly among commentators and spectators at the last America’s Cup in Auckland 2020-21. However, as we are now starting
to understand there are far more elements involved in keeping a high- speed show on the road, not least the way in which both the power that’s generated by the mainsail and the roll stability control of the boat are achieved through the fine control of the mainsheet. Here, hardware experts Harken have been in the front line of development in an area of deck gear that many of us would normally take for granted: the traveller track and car. And while Harken was also involved in other key areas such as the winches and the self-tacking system for the jib, the mainsheet system was the most challenging area. ‘We worked closely with
Emirates Team New Zealand with the development of the AC40,’ explains Mark Wiss, director of global grand prix and custom yacht
56 SEAHORSE
sales at Harken. ‘This collaboration has led to
developments in the deck gear elsewhere too as the new style of sailing develops. For example the bowsprit is gone and now there’s a self-tacking jib so the basic configuration has changed a fair bit since the first concept for the AC75 was announced.’ The evolution of any new class
will always throw up new ideas, layouts and working practices and the deck hardware will adapt to the change. But the AC40 has marked a very different approach. In addition to creating the next generation of America’s Cup machines, the longer- term success of the AC40 also depends on being able to make monohull flight easier to achieve in the broader grand prix racing world outside the Cup circle. And for this to happen the speed and accuracy of the mainsheet system is crucial. As the story of the last America’s
Cup unfolded it became clear that the double-skinned mainsail configuration was far more complex than it looked at first sight. Yes, the outline of the AC75 sail plan marked a return from solid wings, one that was more in keeping with conventional looking racing sails, but from there on, and under closer
Above: fine control of the mainsheet is essential not just for achieving maximum sailpower on a foiling AC boat, it’s also crucial for roll stability. The mainsheet system is working constantly, always near maximum load. Right: different radiuses of main track in testing at HarkenLab
inspection, it has become apparent that the new America’s Cup mainsail configuration is both sophisticated and highly loaded. Be it the AC75 or the smaller one-design AC40, boatspeed in the region of 40kts produces very high apparent wind and narrow apparent wind angles, two factors that contribute to extremely high loads in the clew of the mainsail. And it is this that is the starting point for the new area of development. ‘In principle the tracks and cars
that we’ve supplied for the AC40s are quite a similar setup to what we did on the AC50 catamarans in
AC37
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126
