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does size matter?

reader rant

does size matter?

I have been waiting for some reaction to the new America’s Cup protocol that
restricts model testing to 1:5 scale. Up till now it has been 1:3. Aside
from the commercial implications of this ( only the UK tank claims to be able
to do a meaningful experiment at this scale), what this means is those
syndicates with little or no CFD they believe in, will be unable to do a
valid reliable performance prediction or evaluation of their designs. A
seminal paper by Karl Kirkman in the late seventies showed that this
experiment needs at least twenty foot water line model to be able to evaluate
designs meaningfully.

At a time when there is ostensibly an effort to level
the playing field and make this competition more accessible to more teams,
this is a critical and not much noticed or commented on disadvantage to a new
team starting up, especially if they have no experience with CFD. There are
designers who believe they no longer need tank testing, despite the fact that
they still turn out disappointing race boats. The Yanks lost in 1983 because
they had lost faith in their tank work, and the Dutch found something there
that worked. This looks like a step back in time to where tank testing was
unreliable. But it is mostly a distinct disadvantage to the smaller, newer
teams. Anarchist Bruce.