This is from someone who knows about sailing....
"I cracked the books a bit and ran some numbers yesterday. I think I have a
good reason for the wind speed limit being set where it is. Wow was I wrong. The
boats ended up being faster than they predicted, i.e. the designs were too good.
This put them dangerously close to putting the foils into cavitation speeds
(~50+) that could have lead to real control problems.
Basically they want to limit boat speed to under 50 knots to stay safely out
of foil cavitation speeds. The boats can sail over 2x wind speed and in some
ranges are close to or at 3x wind speed the TWS needed to keep them below 50
knots is in the 22-24 knot range.
The wind limit for safety was not a reaction to the Artemis disaster as I
assumed incorrectly. I had assumed the limit was for structural concerns not an
unforeseen design challenge.
If they want higher wind speed limits they have to lose the foiling to remove
the “50 knot barrier” or they can lose the wing to reduce the top speed of the
boats to under 3x wind speed.
If they want to keep the full foiling and hard wings they are stuck with a
low wind speed limit until they solve the cavitation issue. Sort of ironic that
the faster the boat is relative to wind speed the lower the safe wind speed
becomes. If indeed the wind limit was lowered due to concerns about foil
cavitation then they got it right and the engineering math supports it.
It is not about being pansies, or poor design, or reaction to the Artemis
disaster. It is about unforeseen design success.
Stop bitching about the boats being to fragile to sail in 30+
Start
celebrating that they are too fast to sail in over 25."
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.