12 December 2001
publication, Environmental Monitoring and Operator Guidance System (EMOGS)
Overall Technical Description, DTRC Report SHD-1283-16, provides for further details.
The EMOGS, as installed at Kings Bay to protect OHIO class submarines,
is used because it is not economically feasible to dredge the channel to
provide safe transits of the vessels in all weather conditions. EMOGS
provides the clearance between the vessel hull and the bottom in near
real time. EMOGS software uses bottom survey data, statistical and
measured wave and tidal data, and calculated ship motions to assess the
risk of the submarine touching the channel bottom. Where the MicroVAX
computer is not available, there is a manual procedure for carrying out the
calculations; refer to the EMOGS User Handbook by Silver et al. (DTRC
The level of risk is sensitive to sedimentation rates and dredging activities,
and any change in environmental conditions must be represented in the
Carrier Channel Guidance System. A guidance system was developed
to reduce the risk of aircraft carriers touching the channel bottom while transiting
entrance channels at Norfolk, Mayport, Pensacola, San Diego, and Pearl Harbor. This
system is used by the navigation officer to determine the advisability of transiting the
channel at a scheduled date and time. The system is PC based and is set up in the
Meteorological Office aboard ship. The system provides the predicted clearance
between the vessel hull and the bottom in near real time using bottom survey data,
statistical and measured meteorological data, water depth measurements and
calculated ship motions.
MARINE IMPROVEMENT AND SHORE PROTECTION. Coastal
engineering problems may be classified into four general categories: shoreline
stabilization, backshore protection (from waves and surge), and inlet stabilization and
harbor protection (Figure 5-30). A coastal problem may fall into more than one
category. Once classified, various solutions are available to the coastal engineer.
Some of the solutions are structural; however, other techniques may be employed such
as zoning and land-use management. The primary types of coastal structures and
methods of marine improvement and shore protection are discussed in Chapter 7.