Saturday, January 31, 2015

IMOCA 60 BPVIII : foil lessons


In the IMOCA class, the transition to foils was a logical evolution.

The first change was to tilt the keel axis (keel rotation axis angled with respect to the water plane of the boat, typically angles between 4 and 9° with the new one design keel IMOCA) to create an angle attack on the keel and thus sustain the boat.

The direct consequence of this angle of tilt is the lose of righting moment because the force is applied windward.
The continuity of this philosophy was to work on the foils to regain the righting moment lost by the keel (the faster geos the boat, the more vertical forces are created by the keel and foil and then even faster goes the boat).
All the VPLP-Verdier 60 foot signed in 2015 will all be equipped with foils.
Each team has a specific brief for these foils, so that each pair of foil will be specific.
The six new IMOCA fleet will be very rich for this new page in the offshore racing monohull story.
We already know that there will be a significant gain in speed; the foils could win two days on a Vendée Globe.
The real gains will be for reaching and downwind sailing.
Upwind, it will be more complicated, but it's only represent 10% on a Vendée Globe.

And what next?
What developments could result from the emergence of these new appendages ? ...
The foils "enlarge virtually" from a significant amount the hull beam.
Why not reduce the beams of the boats? ...
To be continued ... "

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