4.1.1 Watertight
doors and hatches are to be designed in accordance with a recognised
Standard. They are to be manufactured under LR Survey and surveyed
during installation. They are to be tested in accordance with the
LR survey procedures, operated under working conditions and tested
in place, see
Vol 1, Pt 6, Ch 6 Material and Welding Requirements.
4.1.2 Doors
and hatches are to be of equivalent strength to the unpierced subdivision.
They are to be approved for the maximum head of water indicated by
the approved damage stability calculations.
4.1.3 Where
watertight doors of the sliding type are permitted by the subdivision
and stability standard, they are to be capable of being operated by
efficient hand-operated gear, both at the door itself and from an
accessible position above the vertical limit of watertight integrity.
Means are to be provided at the remote operating position to indicate
whether the door is open or closed. The time necessary for the complete
closure of the door, when operating by hand gear, is not to exceed
90 seconds with the ship in the upright position.
4.1.4 Power
operated doors are to be capable of being opened and closed locally
by both power and efficient hand operated mechanisms in accordance
with Vol 1, Pt 3, Ch 4, 4.1 General 4.1.3.
4.1.6 Where
manually operated hinged watertight doors are fitted, a suitable procedural
system is to be implemented to ensure that such doors remain closed
when at sea unless specific authorisation is sought.
4.1.7 Watertight
doors and hatches are to be capable of being operated from both sides
of the watertight division except for access to high security areas
such as magazines or to prevent access from open decks.
4.1.8 Sliding
watertight doors are to be capable of being operated up to the heel
and trim angles specified in the subdivision and stability standard,
but not less than 15º heel either way. Consideration is also
to be given to the forces which may act on either side of the door
as may be experienced when water is flowing through the opening, applying
a static head equivalent to a water height of at least 1 m above the
sill on the centreline of the door.
4.1.9 Where practicable watertight access hatches in vertical watertight subdivisions are to
be arranged to allow for the passage of personnel wearing breathing apparatus as well as
the transfer of injured personnel. For this purpose the opening is to be a minimum of
800mm x 600mm. Hand holds and foot holds are to be located on both sides of the
subdivision in the vicinity of the hatch so as to enable ease of access.