2.1.1 The anchoring and mooring equipment specified in this Section is based on an
‘Equipment Number’ which is to be calculated as follows:
where
A
|
= |
area, in m2, in profile view, of the hull,
superstructures, houses, masts, etc. above the design draught which are within the
Rule length of the vessel and also have a breadth greater than B/4. See
also
Vol 1, Pt 3, Ch 5, 2.1 Equipment Number calculation 2.1.2. |
A
t
|
= |
transverse projected area, in m2, of the hull and of all
superstructures, houses, masts, etc. above the design draught |
Δ |
= |
displacement, in tonnes, of the ship at its design draught
waterline. |
2.1.2 Screens and bulwarks more than 1,5 m in height are to be regarded as parts
of houses when determining A. Where a screen or bulwark is of varying height, the
portion to be included is to be that length the height of which exceeds 1,5 m.
2.1.3 For ships which have a complex above water transverse profile due to the
presence of large plated masts, mast trees, large radar equipment, etc. the equipment
number may need to be specially considered.
2.1.4 The Equipment Number formulae for anchoring equipment as given in this
Section are based on an assumed maximum current speed of 2,5 m/s, maximum wind speed of
25 m/s and a minimum scope of 6, the scope being the ratio between length of chain cable
paid out and water depth. For ships with a Rule length, LR, greater
than 135 m, the required anchoring equipment is also considered adequate for a maximum
current speed of 1,54 m/s, a maximum wind speed of 11 m/s and waves with maximum
significant height of 2 m.
2.1.5 The anchoring equipment required herewith is intended for temporary mooring of a ship
within a harbour or sheltered areas when the ship is awaiting berth, tide, etc. It is
designed to hold a ship only in good holding ground conditions such as to avoid dragging
of the anchor. In poor holding ground, the holding power of the anchors would be
significantly reduced.
2.1.6 It is assumed that under normal circumstances a ship uses only one bower anchor and
chain cable at a time.