fivepointfive - April 2023

DAVE HOLLOM ON JEAN GENIE
Where to
from here?
David Hollom talks about the design concepts and challenges
that went into producing the winning boat at the 2022
Scandinavian Gold Cup and World Championship
Looking at the results of the 2022 Worlds in
Hankø you might be forgiven for thinking that
it was a close-run thing and that Jean Genie,
the winner, is nothing special. After all, she only
won by two points. However, in a fleet of boats
that are all very similar to each other, as is the case in the 5.5
Metre fleet, it is very difficult to win by a large points margin
as there will probably be one of the other boats in the fleet
that is on form and almost always comes second, so points
difference is not a good indication of speed. What is a good
indication of speed is the gap at the finish between first and
second and in the four races that Jean Genie won, in most
she was so far ahead that you couldn’t read the sail numbers
of the next boat, which is a large margin. We also made
mistakes, as you sometimes do, wrapping ourselves around
the pin end buoy at one start due to a big windshift and two
other not brilliant starts from which she recovered well.
So what’s so different about this boat? Well firstly she is at
a different part of the rule to pretty much the rest of the fleet.
When I first started researching this project I obviously looked
at where everyone else was situated within the rule, which
seemed to be at around max displacement, max sail area and
min length for that displacement. I also read somewhere that
light long boats with min sail area were only competitive in
light airs. Nevertheless, to satisfy our own curiosity, we ran
boats, which were as near synonyms of each other as possible
having regard to their different displacement requirements,
through our in house VPP (velocity prediction program). This
VPP differs from many others in that the rig coefficients are not
predetermined in any way. They are derived from a rig model
built around aerodynamic theory and are automatically varied
28 • fivepointfive • APRIL 2023