CHAPTER 4 FREEBOARD AND STABILITY

4100. Freeboard

4101. Freeboard to top deck

When the dock is submerged to its maximum draught, the freeboard to the top deck is generally not to be less than l.0 m.

4102. Freeboard to pontoon deck

The freeboard to the pontoon deck with the dock in its final working condition with a ship corre- sponding to the lifting capacity of the dock on the blocks is not to be less than 300 mm at the centerline and not less than 75 mm at the inner wing walls. The dock cranes may be positioned so as to produce no trim.

4103. Freeboard in unsheltered waters

If the dock's port of operation is not sheltered against waves, greater freeboard than given by

4101. and 4102. may be required. 4200. Stability 【See Guidance】

4201. General

The requirements for stability specified in 4202., 4203. and 4204. below apply to the docks oper- ating in sheltered waters and special consideration will be given to the docks operating in areas other than sheltered waters.

4202. Metacentric height, ÄB

In general, the initial metacentric height ÄB is not to be less than 1.0 m in any condition of load- ing as referred to in (1), (2) and (3) below. For transient conditions of short duration, however, a smaller metacentric height ÄB may be accepted upon special consideration.

(1) Dock fully submerged to the minimum freeboard to the top deck.

(2) Dock with pontoon immersed to just below top of keel blocks, with the most unfavourable typi- cal ship supported by the blocks, and restoring water-plane for the combination dock/ship pro- vided on1y by the wing walls of the dock.

(3) Dock in final working condition with typical ships on the blocks, including the most un- favourable ship.

4203. Statical stability diagram

The statical stability diagram including wind heeling moment curve is to be submitted for the de- sign condition of 4202. (3).

In general, the point of intersection between the statical stability curve and the wind heeling mo-

ment curve is un-der no circumstance to exceed the angle where any part of the pontoon deck submerges.

4204. Wind heeling moment

The wind heeling moment may be calculated from the following formula.

LǾĴĪJ × ÌLŇ Ĩ × Đ ĪAÀ (t-m)

where:

A : the longitudinal projected area of the exposed surface considered at every stage of inclining

exposed areas of docked ship (m2).

À Ņ ∆À Ñ ÌÕĪᾘ (m)

∆À : Vertical distance from the center of A to the water line of the dock (m).

ᾘ : draught of the dock (m).

Đ : wind velocity (m/sec), the wind velocity is not to be than 25 m/sec in the values of the wind velocity will depend on the service location and ation of the dock, and may be considered more precisely in each case.

genera1. However, the mode of oper-