1.1 The weather criterion contained in paragraph 3.2 of the Intact Stability Codefootnote shall apply. In applying the weather criterion,
the value of wind pressure P (N/m2) shall be taken as:
where Vw
= wind speed (m/s)
corresponding to the worst intended conditions.
The angle
of heel due to wind, in applying paragraph 3.2.2.1.2 of the Intact Stability Code, shall not exceed 16° or
80% of the angle of deck-edge immersion (whichever is less). Where
the angle of heel due to wind exceeds 10°, efficient non-slip
deck surfaces and suitable holding points shall be provided, in accordance
with paragraph 2.13.1.1 of this Code. In applying the weather criterion,
account shall also be taken of the roll damping characteristics of
individual craft in assessing the assumed roll angle θ1,
which may alternatively be derived from model or full scale tests
using the method for determining θz in 1.1.5.3 of annex 6. Hulls with features which greatly
increase damping, such as immersed sidehulls, substantial arrays of
foils, or flexible skirts or seals, are likely to experience significantly
smaller magnitudes of roll angle. For such craft, therefore, the roll
angle shall be derived from model or full scale tests or, in the absence
of such data, shall be taken as 15°.
1.2 The area under the righting lever curve (GZ
curve) shall not be less than 0.07 
up to θ = 15° when the maximum righting lever
(GZ) occurs at θ = 15° , and 0.055 
up to θ = 30° when the maximum righting lever
occurs at θ = 30° or above. Where the maximum righting
lever occurs at angles of between θ = 15° and θ
= 30°, the corresponding area under the righting lever curve shall
be:
A = 0.055 + 0.001 (30° - θmax ) (m·rad)
where:
|
θmax
|
= |
is the angle
of heel, in degrees, at which the righting lever curve reaches its
maximum. |
1.3 The area under the righting lever curve between θ
= 30° and θ = 40° or between θ = 30° and
the angle of flooding θF, footnote if this angle is less than 40°, shall not
be less than 0.03 
.
1.4 The righting lever GZ shall be at least 0.2
m at an angle of heel equal to or greater than 30°.
1.5 The maximum righting lever shall occur at
an angle of heel not less than 15°.
1.6 The initial metacentric height GMT shall
not be less than 0.15 m.