The strength of securing devices should comply with the
.1 Panel hatch covers should be secured by appropriate
devices (bolts, wedges or similar) suitably spaced alongside the coamings
and between cover elements. Arrangement and spacing should be determined
with due attention to the effectiveness for weather-tightness, depending
upon the type and the size of the hatch cover, as well as on the stiffness
of the cover edges between the securing devices.
.2 The net sectional area of each securing device
is not to be less than:
securing devices not to be taken less than 2 metres
minimum upper yield stress in N/mm2 of the steel used for
fabrication, not to be taken greater than 70% of the ultimate tensile
|0.75 for σY >
|1.0 for σY ≤ 235
Rods or bolts should have a net diameter not less than 19 mm
for hatchways exceeding 5 m2 in area.
.3 Between cover and coaming and at cross-joints,
a packing line pressure sufficient to obtain weathertightness should
be maintained by the securing devices. For packing line pressures
exceeding 5 N/mm, the cross section area should be increased in direct
proportion. The packing line pressure should be specified.
.4 The cover edge stiffness should be sufficient
to maintain adequate sealing pressure between securing devices. The
moment of inertia, I, of edge elements be less than:
|packing line pressure
in N/mm, minimum 5 N/mm
|spacing in m of
.5 Securing devices should be of reliable construction
and securely attached to the hatchway coamings, decks or covers. Individual
securing devices on each cover are to have approximately the same
.6 Where rod cleats are fitted, resilient washers
or cushions should be incorporated.
.7 Where hydraulic cleating is adopted, a positive
means should be provided to ensure that it remains mechanically locked
in the closed position in the event of failure of the hydraulic system.