UFC 4-150-06
12 December 2001
Channels. General channel classifications and elements are shown on
Figure 5-2.
5-6.1.1.5
Economics. Economic considerations must be weighed against depth
requirements. In harbors where tidal range is very large and, particularly, where an
entrance channel is long, consider the possibility of restricting the entrance of the
largest draft ships using the harbor to the higher tidal stages. Where hard bottoms
prevail and excavation costs are high, consider the exclusion of certain classes of deep-
draft vessels, with provision of lighter service between deep-water anchorage and
docks.
5-6.1.2
Depth Requirements. In general, the depth of harbor areas varies.
Certain areas are reserved for small craft usage while larger ships are set aside for
larger ships. Additionally, channel depth requirements differ from those at anchorages
and berths. Depending upon the specific area under consideration, it is imperative to
provide for adequate depths at all anticipated water levels.
5-6.1.2.1
Naval Vessel Characteristics. Table 5-3 presents some of the
characteristics of auxiliary and combatant vessels and service craft. In cases where the
harbor design requires critical clearances for a particular vessel type or condition,
specific verification by the Naval Sea Systems Command (NAVSEA) Ship Logistic
Manager is required.
5-6.1.2.2
Preliminary Design Depth. Table 5-3 also provides suggested design
depths for preliminary design purposes. These values were developed to incorporate
certain generalized approximations of overdepth allowances for such parameters as
static eccentricities, wave motion, and bottom-clearance allowances. Should unique
siting or vessel conditions be critical in harbor-depth selection, a detailed analysis of all
factors is required. Once the vessel type is known, the designer should obtain the
maximum navigational draft to determine if the proposed depth is great enough to avoid
interference with the vessel's hull and, in the case of destroyers, cruisers, and frigates,
any special electronic gear that may be attached.
Anchorage and Berthing Areas. For a specific vessel, the depth
requirements at anchorage and berthing areas are the same. The
required depth for an undamaged vessel is determined by adding 1.2
meters (4 feet) to the maximum navigational draft (Table 5-3). Berthing
depths for floating drydocks are given in Table 5-4; note that these
estimates are based upon the maximum submerged draft plus 0.6 meters
(2 feet).
Channels. In the case of a fully operational channel protected from direct
storm-wave attack, the desirable ratio of channel depth to navigational
draft of the largest vessel should be 1.3 for vessel speeds of less than 7
knots, and 1.5 for vessel speeds in excess of 7 to 8 knots. At these
ratios, the bottom effects on vessel handling become negligible. In many
cases, these desired criteria cannot be obtained. For general design
5-10
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