5.3.1 In all conditions of loading necessary care
should be taken to maintain a seaworthy freeboard.
5.3.2 In severe weather, the speed of the ship
should be reduced if propeller emergence, shipping of water on deck
or heavy slamming occurs.
5.3.3 Special attention should be paid when a
ship is sailing in following, quartering or head seas because dangerous
phenomena such as parametric resonance, broaching to, reduction of
stability on the wave crest, and excessive rolling may occur singularly,
in sequence or simultaneously in a multiple combination, creating
a threat of capsize. A ship's speed and/or course should be altered
appropriately to avoid the above-mentioned phenomena.footnote
5.3.4 Reliance on automatic steering may be dangerous
as this prevents ready changes to course which may be needed in bad
weather.
5.3.5 Water trapping in deck wells should be avoided.
If freeing ports are not sufficient for the drainage of the well,
the speed of the ship should be reduced or the course changed, or
both. Freeing ports provided with closing appliances should always
be capable of functioning and are not to be locked.
5.3.6 Masters should be aware that steep or breaking
waves may occur in certain areas, or in certain wind and current combinations
(river estuaries, shallow water areas, funnel shaped bays, etc.).
These waves are particularly dangerous, especially for small ships.
5.3.7 In severe weather, the lateral wind pressure
may cause a considerable angle of heel. If anti-heeling measures (e.g.,
ballasting, use of anti-heeling devices, etc.) are used to compensate
for heeling due to wind, changes of the ship's course relative to
the wind direction may lead to dangerous angles of heel or capsizing.
Therefore, heeling caused by the wind should not be compensated with
anti-heeling measures, unless, subject to the approval by the Administration,
the vessel has been proven by calculation to have sufficient stability
in worst case conditions (i.e. improper or incorrect use, mechanism
failure, unintended course change, etc.). Guidance on the use of anti-heeling
measures should be provided in the stability booklet.
5.3.8 Use of operational guidelines for avoiding
dangerous situations in severe weather conditions or an on-board computer
based system is recommended. The method should be simple to use.
5.3.9 High-speed craft should not be intentionally
operated outside the worst intended conditions and limitations specified
in the relevant certificates, or in documents referred to therein.