4.12.1 Anchoring arrangements, where fitted as
the sole means for position keeping, should be provided with adequate
factors of safety and be designed to maintain the unit on station
in all design conditions. The arrangements should be such that a failure
of any single component should not cause progressive failure of the
remaining anchoring arrangements.
4.12.2 The anchors, cables, shackles and other
associated connecting equipment should be designed, manufactured and
tested in accordance with an internationally recognized standard for
offshore mooring equipment. Documentation of testing, where applicable,
should be maintained on board the unit. Provisions should be made
on board for the recording of changes to and inspection of the equipment.
4.12.3 Anchor cables may be of wire, rope, chain
or any combination thereof.
4.12.4 Means should be provided to enable the
anchor cable to be released from the unit after loss of main power.
4.12.5 Fairleads and sheaves should be designed
to prevent excessive bending and wear of the anchor cable. The attachments
to the hull or structure should be such as to adequately withstand
the stresses imposed when an anchor cable is loaded to its breaking
strength.
4.12.6 Suitable anchor stowage arrangements should
be provided to prevent movement of the anchors in a seaway.
4.12.7 Each windlass should be provided with two
independent power-operated brakes. Each brake should be capable of
holding against a static load in the anchor cable of at least 50%
of its breaking strength. Where the Administration so allows, one
of the brakes may be replaced by a manually operated brake.
4.12.8 The design of the windlass should provide
for adequate dynamic braking capacity to control normal combinations
of loads from the anchor, anchor cable and anchor handling vessel
during the deployment of the anchors at the maximum design payout
speed of the windlass.
4.12.9 On loss of power to the windlasses, the
power-operated braking system should be automatically applied and
be capable of holding against 50% of the total static braking capacity
of the windlass.
4.12.10 Each windlass should be capable of being
controlled from a position which provides a good view of the operation.
4.12.11 Means should be provided at the windlass
control position to monitor cable tension and windlass power load
and to indicate the amount of cable paid out.
4.12.12 A manned control station should be provided
with means to indicate and automatically record cable tensions and
the wind speed and direction.
4.12.13 Reliable means should be provided to communicate
between locations critical to the anchoring operation.
4.12.14 Special consideration should be given
to arrangements where the anchoring systems provided are used in conjunction
with thrusters to maintain the unit on station.