1.2.1 The stability should satisfy 2.5 of this Code.
1.2.2
-
(a) The stability in the transient and foil-borne
modes should be checked for all cases of loading for the intended
service of the craft.
-
(b) The stability in the transient and foil-borne
modes may be determined either by calculation or on the basis of data
obtained from model experiments and should be verified by full-scale
tests by the imposition of a series of known heeling moments by off-centre
ballast weights, and recording the heeling angles produced by these
moments. When taken in the hull-borne, take-off, steady foil-borne,
and settling to hull-borne modes, these results will provide an indication
of the values of the stability in the various situations of the craft
during the transient condition.
-
(c) The time to pass from the hull-borne mode
to foil-borne mode and vice versa should be established. This period
of time should not exceed two minutes.
-
(d) The angle of heel in the foil-borne mode caused
by the concentration of passengers at one side should not exceed 8°.
During the transient mode the angle of heel due to the concentration
of passengers on one side should not exceed 12°. The concentration
of passengers should be determined by the Administration, having regard
to the guidance given at Appendix Ill to
this Code.
1.2.3 One of the possible methods of assessing
foil-borne metacentric height (GM) in the design stage for a particular
foil configuration is given in Figure 3.
Figure 3 Possible method of assessing foil-borne metacentric height (GM)
where
|
nB
|
= |
percentage
of hydrofoil load borne by front foil |
|
nH
|
= |
percentage
of hydrofoil load borne by aft foil |
|
LB
|
= |
clearance
width of front foil |
|
LH
|
= |
clearance
width of aft foil |
|
a |
= |
clearance between
bottom of keel and water |
|
g |
= |
height of centre
of gravity above bottom of keel |
|
1B
|
= |
angle
at which front foil is inclined to horizontal |
|
1H
|
= |
angle
at which aft foil is inclined to horizontal |