CETN I-63
March 1999
DETERMINATION OF CHANNEL WIDTH: The optimum channel width varies with many
factors, including channel alignment, transit routes, construction and maintenance costs, vessel
transit time, vessel speed and maneuverability, horizontal vessel movements caused by winds,
waves, and currents, proximity of channel banks, traffic pattern (one-way versus two-way
traffic), and availability and frequency of navaids. The channel width, measured from the
bottom of the side slopes at the design depth, must accommodate the design vessel(s). The
authorized channel width must allow normal vessel operations in a safe and efficient manner.
Crosscurrents and winds adversely affect the station keeping and maneuvering of vessels, and
quartering seas may cause the vessel to deviate from its route. USACE guidance for channel
width states:
"For one-way ship traffic, values for channel width vary from 2 to 7 times the design ship beam.
Typically a range of 2.5 to 5 is used as design criteria. For straight one-way channels with low
currents, widths of 2 or 2.5 times the design ship beam should generally be conservative.
Recommending a similar criteria for two-way ship traffic is difficult due to lack of data"
(USACE 1984, 1995, 1999).
Historically, width requirements have been based on piloting experiences and the accuracy with
which pilots are able to transit entrance channels for various environmental and vessel-handling
characteristics. Currently, the final design-width requirements are usually considered through
the use of virtual ship simulators, which recreate the scene dynamics and horizontal vessel
responses because of ship maneuvers taken by actual pilots in the simulator. Further research is
needed to quantitatively establish horizontal vessel responses because of waves (and currents)
and to incorporate those results into a preliminary design tool and enhanced ship simulator.
ADDITIONAL INFORMATION:
For additional information, contact Dr. Zeki Demirbilek (Voice: (601) 634-2834, e-mail:
) or Mr. Frank Sargent (Voice: (601) 634-3586, e-mail:
). This technical note should be cited as follows:
Demirbilek, Z., and Sargent, F. (1999). "Deep-draft coastal navigation entrance
channel practice," Coastal Engineering Technical Note CETN I-63, U.S. Army
Engineer Research and Development Center, Vicksburg, MS.
REFERENCES/BIBLIOGRAPHY:
Ankudinov, V. et al. (1996). "Squat predictions for maneuvering applications." Marine
simulation and ship maneuverability. M. Chislett, ed., Balkema, Rotterdam.
Demirbilek, Z. and Panchang, V. (1998). "CGWAVE: A coastal surface water wave model of
the mild slope equation," Technical Report CHL-98-26, U.S. Army Engineer Waterways
Experiment Station, Vicksburg, MS.
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