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SVN Solovelanet Global
Moving the keel upwind subjects the hull and the rig
to very significant loads. On Maxi yachts equipped
with canting keels, hydraulic pistons move keels with
a draft of more than 5 meters and bulbs that weigh
up to 10 tons or more.
The load generated by the lever affects the structure
of the hull in the order of dozens of tons. For this
reason, a boat designed to sail with a canting keel
must be extremely sturdy.
Another problem with canting keels is a decrease
in lift, which is directly proportional to the increase
in the displacement angle: the more the keel is mo
-
ved from its central axis, the less lift it will have and
the more the leeway will increase. To compensate
for this loss in lift, all boats equipped with a canting
keel have additional appendages capable of moving
vertically: either a canard, that is, a central fin pla
-
ced forward of the keel, or two symmetrical lateral
daggerboards. In general, canting keels offer signi-
ficant gains in performance but are also complex
systems prone to structural problems. During the
latest edition of the Vendée Globe, there were four
withdrawals caused by problems with or loss of the
canting keel. It is possible that future developments
will make this technology more reliable.
"...the shortcoming of a
canting keel consists in a
decrease in lift of the appen-
dage, that is directly propor-
tional to the increase in the
displacement angle ..."
On top, the forecourt of the Fora
Marine shipyard, specialized in bu-
ilding the RM wooden boats with
a twin keel.. Here above, some
boats equipped with twin keels in
a harbour during low tide. Aside,
a Fora Marine RM 890 during a
Solovelanet test
Jean Bonnet was born in Sant Malo and
has lived many years in Atlantic France,
where he worked on high-tech construc-
tion projects at several shipyards.
The author
