| Objective: This Chapter provides for consideration of the risks
of green water being shipped aboard and the resulting consequences
with respect to the vessels stability and safety of personnel on
deck.
|
6.1 General Requirements
(1) The standards for
water freeing arrangements shall comply with ICLL on any weather decks in the
forward quarter, and up to Position 2 elsewhere. In any case the intention shall be
to achieve a standard of safety which is at least equivalent to the standard of the
ICLL to the satisfaction of the Administration given the design and use of the
vessel.
(2) Additionally, where a well is created on each side of the vessel
between a superstructure or deckhouse, and the bulwark in way of that superstructure
or deck house, the following formula may be used to determine the required freeing
port areas on each side of the vessel for the well concerned:
(3) On sailing vessels, where the solid bulwark height does not exceed 150
millimetres, specific freeing ports, as defined above, are not required.
(4)
For Short Range Yachts, it is considered that the requirement for freeing port area
for a forward or aft well may be reduced by a form factor equal to the ratio of
(actual area well) divided by (length of well x breadth of well). Dimensions shall
be taken at half height of the bulwark. This may be reduced by 50% providing it can
be shown that the intact stability of the yacht remains acceptable if the well is
flooded to any level up to the bulwark height and that area provided shall allow the
well to drain in less than 3 minutes.
6.2 Recesses
(1) Any recess in the weather deck shall be of weathertight construction and shall be
self draining under all normal conditions of heel and trim of the vessel.
A swimming pool or spa bath, open to the elements, shall be treated as a recess.
(2) The means of drainage provided shall be capable of efficient operation when the
vessel is heeled to an angle of 10º in the case of a motor vessel (see 10A.2), and
30º in the case of a sailing vessel.
(3) The drainage arrangements shall have the capability of draining the recess (when
fully charged with water) within 3 minutes when the vessel is upright and at the
load line draught. Means shall be provided to prevent the backflow of sea water into
the recess.
(4) When it is not practical to provide drainage which meets the requirements of
6.2(3), alternative safety measures may be proposed for approval by the
Administration. Where the above requirements for quick drainage cannot be met, the
effect on intact and damage stability shall be considered taking into account the
mass of water and its free surface effect.
6.3 Swimming Pools (Including Spa Baths and Jacuzzis)
(1) All swimming pools shall have their effect on intact and damage stability
considered taking into account the mass of water and its free surface effect.
(2) If there are loading conditions where swimming pools shall be emptied in order to
comply with stability requirementsfootnote of Chapter 11, these loading conditions shall be
placed in a separate section of the approved stability booklet with the following
note added:
| In this loading condition the vessel may not have
its [swimming pool] [spa bath] [jacuzzi] full, due to insufficient
stability
|
(3) All loading conditions included in the approved stability book shall be shown to
meet the damage stability requirements of Chapter 11.
6.4 Additional Equivalence Considerations
(1) Freeing arrangements may take account of a reduced permeability and volume of the
well, when compared to a full size well.
(2) For existing vessels, the Administration may take into account the vessel’s past
performance in service, the declared area(s) of operation and any other conditions
which restrict the use of the vessel at sea which shall be recorded on the
International Load Line Certificate issued to the vessel (see Section 4.1(3)).