The new boundaries imposed on the
navigation of competition yachts with regard to water-ballats and
Racing yachts are evolving ; gaining in stability, solidity and
speed. Until now sea-going racing yachts had a limited speed : the
kinetic energy of the boat when sailing was as significant as the
energy necessary to capsize. After a sudden rounding-up or bearing-off
she would keel-over.
Modern boats with water-ballasts and a mobile keel are much faster
and thus the kinetic energy becomes a very important factor. In
addition, their stability curve becomes asymmetrical so that when
they are rounding-up they stop as before, because both stability
and kinetic energy have increased.
On the other hand, when they are bearing-off the situation
becomes more dangerous. Their kinetic energy has become much higher
but, at the same time, the energy necessary to capsize to leeward
is much less (because the stability has decreased on this side).
In the case of the mobile keel the situation is even more delicate
because in this position the winward leaning keel becomes vertical
to leeward and facilitates capsizing by blocking the movement of
In most cases, the boat stops after gybing. However, it is important
to be aware that if the pilot loses control it causes a sudden reaction
which can make the boat capsize under its own speed (this in spite
of the increased stability that new technology recently introduced
to the boats), like a car when the steering wheel is turned quickly.
After such an accident the boat has the capacity to right itself
but represents a very dangerous situation for the crew on deck.
Modern boats have new possibilities, they can navigate better
and faster but it is important to remain vigilent and be conscious
of the new limits and new dangers.