In addition to these factors a number of others influence fender 
design: tidal variations, velocity and direction of winds and currents, 
types of ships, availability of tugs, difficulty of approach, amount of 
list in vessels, and design life of facility. 
2.4.3 Mooring Dolphins. As part of the pier mooring system, sepa- 
rate mooring dolphins may be installed to absorb the lateral loads from 
the ship thus reducing berthing loads imposed on the pier. They can be 
designed either as piled, tension-leg or gravity type structures. The 
simplest form is a piled or flexible dolphin, which consists of a number 
of wood, steel or concrete piles. The number and type of piles are 
dependent on bottom soil conditions, height of the dolphin, and magni- 
tude of the forces acting on the dolphin. Tension leg dolphins rely on 
the horizontal component of the force in the anchor legs to provide 
restoring force. Gravity dolphins are usually designed in the form of 
cribs or cells filled with granular material or rock. Gravity dolphins 
may also be constructed using seawater ballast in conjunction with a 
structure to resist movement. 
2.5 Approachway Design 
The approachway is the link between the floating pier structure and 
the shore. As such, the approachway must provide effective movement of 
cargo and material handling equipment and personnel. Typical schemes 
for constructing an approachway include: 
e Access bridges 
@ Floating bridges 
e Pile-founded causeway systems 
The approachway may be the extension of a causeway system installed 
during the Assault Follow On phase of an amphibious operation or it may 
be purposely built to coincide with the installation of the floating 
pier structure. In either case this is viewed as an undertaking which 
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