JALhazmat
Super Anarchist
the odds were that one team would..
Alinghi Challenge AC37
- Thread starter strider470
- Start date
Chobani Sailor
Anarchist
Without getting too technical the winning team went with straight foil wings. the losing teams went with an anhedral shape foil wing. When AC40s are launched at the end of 2022 it will be interesting to see what shape teams are experimenting withone team seemed to get it better than the others?
shebeen
Super Anarchist
simplistically, ETNZ had the smallest foils. therefore lowest drag and best ones in high wind (which we never saw).one team seemed to get it better than the others?
but they were still able to get the whole contraption out of the water in low wind conditions, which was surprising.
this didn't make sense, to a simpleton like me, but I don't think cavitation mastery was the golden ticket to this bus ride
enigmatically2
Super Anarchist
Maybe. Thing is that smaller foils tend to give you a higher pressure differential (to lift the same weight from a smaller area they have to) so they are liable to cavitate earlier. Did the others back off from such a design because they couldn't solve the cavitation problem?
Did any team ever hit the cavitation limit?
I don't know. But I would particularly like to know the answer to the last question.
I think you are right and that the key was getting enough lift from smaller foils. But I'm not sure there wasn't some advantage at the cavitation end too
JALhazmat
Super Anarchist
JALhazmat
Super Anarchist
AM had the fastest speed through any Racing, NZ were the slowest.
rumours of 58 kts are just that.
barfy
Super Anarchist
- 5,447
- 1,590
There were serious advances in managing ventilation made by all teams. When the pundits here first saw the 75's with a foil tip breaching there was some surprise the ventilation didn't cause a loss of lift and immediate crash. By the cycle end all teams were riding a tip out to varying degrees. Whether this was just for geometric advantage like RM, for increased lift upwind, or was being utilized to reduce drag we just don't know. @Basiliscus mentions that this aspect of foil simulation and practice is the most murky, the "golden ticket" may reside here.
P Flados
Anarchist
As far as getting the boat up foiling in low wind, I am not sure what was the secret to ETNZ performance. Hull shape, sail and foil all matter.
shebeen
Super Anarchist
yes of course. all part of the package and tradeoffs. Foil choice was locked in a few days before each race period so one of the big decisions, almost backfired on that one driftathon in the Cup race.
barfy
Super Anarchist
- 5,447
- 1,590
floater
Super Duper Anarchist
hull shape mattered? that is certainly one differentiator in this foiling war - what's a shearline, and what is it goodfor?
Sailbydate
Super Anarchist
Sheer line you mean? They ain't what they used to be, that's for sure.
These days sheers are all cut away to reduce windage and shed water. They're commonly also reversed (accomodating next to no hull rocker, in flatter and slightly deadrised planning hulls).
My layman's understanding, of course ;-)
floater
Super Duper Anarchist
well sure. but I am beginning to think it might have gone too far, when your hull gives way to a fuselage.
Sailbydate
Super Anarchist
floater
Super Duper Anarchist
I guess the point I'm trying to make is the rule may have gotten too mechanical. I like foiling - but the pure foiling of an A-class catamaran is a much prettier aesthetic to my mind (no active foil controls - just boards in water). all the grinding makes the AC boats look like power boats - shit, some poster on here literally wanted to power them up via solar panels (not naming any names ;-). And if the cyclors climb back aboard - it becomes even more problematic.
how many of us even on this forum have an intuition what all that hydraulic power is used for? I can only guess. but in the good ol days a main sheet was simply managed with a set of blocks..
how many of us even on this forum have an intuition what all that hydraulic power is used for? I can only guess. but in the good ol days a main sheet was simply managed with a set of blocks..
Sailbydate
Super Anarchist
floater
Super Duper Anarchist
no cyclors needed.
