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to keep the ship off the facility and diminish the possibility of damage to the
structure and ship. At oil storage terminals located in areas where
meteorological and hydrological conditions are severe, consider using a single
point mooring which allows a moored tanker to swing freely when acted upon by
winds, waves, and currents from varying directions. See UFC 4-159-03.
A pier is oriented either perpendicular to or at an angle with the shore. There are
generally slips on both sides, although there are instances where only one side
has a slip because of site conditions or because there is no need for additional
berthing. Piers may be more desirable than wharves when there is limited space
available because both sides of a pier may be used for mooring ships. When
both sides of a moored ship need to be accessed, two parallel piers with a slip in
between may be preferred. Magnetic Treatment and Electromagnetic Roll piers
usually require a magnetic north/south orientation, irrespective of other
A wharf is a structure oriented approximately parallel to the shore. Ships can
only be moored at the offshore face of a wharf. When water depths close to
shore are not adequate to accommodate deep draft ships, the wharf, consisting
of a platform on piles, is located offshore in deep water and is connected to shore
at one or more points by pile-supported trestles, usually at right angles to the
wharf. If the trestle is located at the center of the wharf, the structure is referred
to as a T-type wharf; if the trestle is located at an end, the facility is known as an
L-type wharf; if trestles are located at both ends, the wharf is called a U-type
wharf. Ships may be berthed on both sides of a T- or L-wharf. When the
offshore wharf is used for transfer of bulk liquid cargo from the unloading platform
to shore via submarine pipelines, the structure is referred to as an island wharf.
A trestle from the offshore wharf to shore is not provided and both sides of the
island wharf may be used for mooring ships. Launches are used for wharf
access. Where a U-shaped berth is formed by a cut into land by two
approximately parallel wharves, this may be referred to as a slip. For examples
of pier and wharf types, see Figures 2-1 and 2-2. For general cargo, supply, and
container terminals, a wharf structure, connected to upland shore area for its full
length, is preferred because such an arrangement is more adaptable to loop rail
and highway connections and the distance from wharf apron to transit sheds and
open storage areas is shorter.
Vessel Ingress and Egress.
On occasion, a moored vessel is required to make a hasty departure from its
berth and head out to sea. Accordingly, when planning a pier or wharf, consider
providing adequate turning area so that a ship can be turned before it is docked,
and moored with a heading that will permit a convenient and rapid departure.