Comentarii la: Cât de repede poate merge de fapt o barcă cu pânze cu pânze?!?!?

De: surfcello

surfcello — Fri, 30 Sep 2022 08:25:48 +0000

Great video, but I'm not yet entirely convinced by your explanation. Cavitation occurs when the pressure locally gets to below the boiling point of the water, so the water spontaneously turns gaseous, and this can cause stalling of a foil. I understand that this becomes more and more likely at higher speeds for a given angle of attack and foil curvature. But do you have any explanation for this magical number of 50 knots? Couldn't one simply use a slimmer foil profile and a lower angle of attack at higher speeds? Or is this not possible due to structural limitations?

Also I assume you meant "sound barrier" in a figurative way? I see no physical resemblance to the challenge of breaching the sound barrier in aircraft.

De: Kilo Whisky

Kilo Whisky — Thu, 29 Sep 2022 07:32:05 +0000

Engineers knows how to design a foil to push the cavitation limit at high speed. But this mean your foil will be even less efficient in light wind (that's also why it's easier on short race to go faster than 55 knots if such a boat is designed – Syrocco?-). Ultimate class is working a lot on aerodynamics and, from what I know, a lot on a new foil (tip part of the mid hull) that will be in "reverse" (dragging the boat down to the sea where other foil lift) to enable more power to be transmitted form the sails. Next race (Route du Rhum) they should be even faster.

De: Cbob64

Cbob64 — Thu, 29 Sep 2022 06:21:54 +0000

Regarding IMOCA, they are not full foiling boat (i.e. Hugo BOSS )as today, lifting rudders are forbidden.

De: Cbob64

Cbob64 — Thu, 29 Sep 2022 06:17:03 +0000

These Utlim 32 boats are beast, way more interesting than AC boats.

De: streetsailor

streetsailor — Thu, 29 Sep 2022 02:16:40 +0000

And then there's Sailrocket at 65.45 knots over 500 meters! Peak speed 68 knots. Must have been some crazy hydrodynamics happening around her single foil.

De: pforce9

pforce9 — Thu, 29 Sep 2022 00:19:12 +0000

So all they have to do is solve the cavitation problem and make adjustable foils and they can go faster?

De: John Kobbeman

John Kobbeman — Wed, 28 Sep 2022 23:21:13 +0000

France's SailGP boat hit 99.9 kph briefly(just under 54 knots) a few weeks ago, and that is a new top speed record for that race series. They were seriously moving.

De: Paddy H.

Paddy H. — Wed, 28 Sep 2022 21:40:04 +0000

Very interesting! Thanks

De: Rick Emmet

Rick Emmet — Wed, 28 Sep 2022 19:33:50 +0000

Great video, nice to see this being address seriously. Yeah, it's not safe foiling over long distances, the best helmsmen in the world crash their foiling multis on a regular basis. The Eagle 53 has had its T-foils installed, but they haven't put out a video on this new addition to the design. I suspect that the software required to make the boat foil safely hasn't yet been figured out.

De: Anton Tromp

Anton Tromp — Wed, 28 Sep 2022 15:12:19 +0000

Why dont they Dimple the foils like a golf ball to avoid cavitation?