8. The effect on stability of free surface in each tank in the ship in which
liquids may be carried, including an example to show how the metacentric
height is to be corrected.
9. (1) A diagram or table showing cross curves of stability, covering the
range of draughts referred to in paragraph 7(1).
(2) The information shall indicate the height of the assumed axis from
which the righting levers are measured and the trim which has
been assumed.
(3) In the case of ships having raked keels and where a datum other
than the top of keel has been used, the position of the assumed axis
shall be clearly defined.
(4) Subject to subparagraph (5), only enclosed superstructures and
efficient trunks as defined in paragraph 10 of Schedule 4 shall be
taken into account in deriving such curves.
(5) The following structures may be taken into account in deriving such
curves if the Secretary of State is satisfied that their location, integrity
and means of closure will contribute to the ship’s stability –
(a) superstructures located above the superstructure deck;
(b) deckhouses on or above the freeboard deck whether wholly or
in part only;
(c) hatchway structures on or above the freeboard deck.
(6) Subject to the approval of the Secretary of State in the case of a ship
carrying timber deck cargo, the volume of the timber deck cargo, or a
part thereof, may be taken into account in deriving a supplementary
curve of stability appropriate to the ship when carrying such cargo.
(7) An example shall be included to show how a curve of righting
levers (GZ) may be obtained from the cross curves of stability.
(8) In the case of a vehicle ferry or a similar ship having bow doors,
ship-side doors or stern doors where the buoyancy of a superstructure
is taken into account in the calculation of stability information,
and the cross curves of stability are based upon the assumption that
such doors are secured weather-tight, there shall be a specific warning
that such doors must be secured weather-tight before the ship
proceeds to sea.
10. (1) The diagram and statements referred to in subparagraph (2) shall be
provided separately for each of the following conditions of the ship –
(a) light condition. If the ship has permanent ballast, such diagram
and statements shall be provided for the ship in light condition
both with and without such ballast;
(b) ballast condition both on departure and on arrival. It is to be
assumed that on arrival oil fuel, fresh water, consumable stores
and the like are reduced to 10 per cent of their capacity;
(c) condition on departure and on arrival when loaded to the Summer
load line with cargo filling all spaces available for cargo. Cargo shall
be taken to be homogeneous except where this is clearly inappropriate,
for example, in cargo spaces that are intended to be
used exclusively for the carriage of vehicles or of containers;