A rigid wing is a disaster on a sailing boat unless the boat is used in calm water or the platform rides above waves and does not roll at anchor or at quayside.
The problem with a rigid wing is a combination of its inertia and having a very narrow angle where there is no drive. A soft sail can be easily feathered by releasing the sheet. It will flog in high wind but will not offer drive; just drag. A rigid wing offers drive as soon as it moves a fraction off alignment. As soon as it moves, the platform rolls due to the drive and that will pump ever increasing oscillations until something breaks or the platform capsizes.
A soft sail flogging violently is bliss compared with a rigid wing rolling the whole boat violently. And the flogging sail can be lowered in a matter of seconds or loaded to stop it flogging.
As far as I know there is only one water based platform with a rigid wing that has bettered the speed of kites, which are not rigid.
On 12 Jun 2018, at 3:25 pm, realink@iprimus.com.au [harryproa] <harryproa@yahoogroups.com.au> wrote:Ive no doubt rigid is faster. and not by a bit but a lot faster. Greenbird managed 126 mph on land. The thing here is that reefing probably isnt reliably possible so the wing relies upon a zero AoA set. The profile drag at zero lift is better than a reefed standing rig, but I know what concerns Rob is what happens if the wind shifts and the bearing sticks.
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Posted by: Rick Willoughby <rickwill@bigpond.net.au>
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