UFC 4-150-06
12 December 2001
In addition to rudder-angle and vessel-handling criteria, overall vessel
safety must be considered in determining bank-clearance distance. In an open
channel, the markings of the channel limits may not be as fully defined as in a restricted
channel. This can be compounded in times of poor visibility. Similarly, where there
exists a high damage probability for grounding, as in the case of an underwater rock
ledge, additional bank-clearance margins should be considered. Extra allowance
should also be made where the channel is subject to siltation from the side slopes.
Under conditions such as those mentioned above, the minimum desired bank clearance
for design purposes should be equal to the beam of the largest vessel frequenting the
harbor. For open channels with steeper than 1-on-3 side slopes, this minimum
clearance should be 1.2 times the beam. Examples of existing interior channels are
given in Table 5-9.
5-6.2.2.2
Channel Bends. Bends in channels should be avoided if possible. If
channel bends are unavoidable, the channel should be widened to account for the fact
that the path of a ship in a bend is wider than in straight sections. The criteria for
designing channel bends depend upon:
The angle of deflection, defined as the angle between the two straight
sections of the channel,
The speed of travel of and the properties of the vessel,
The characteristics of the channel,
The visibility, obstructions, and aids to navigation in the vicinity of the
bend, and
Human elements.
5-47
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