airborne vehicles, remotely operated vehicles, ship-to-shore communications and telepresence, and ocean observing systems. As the number and complexity of seagoing systems increase, so does the need for broadly trained and highly skilled technicians to maintain them, a topic covered briefly at the conclusion of this chapter.

DYNAMIC POSITIONING

One of the technologies already in use on many oceanographic research ships is dynamic positioning (DP). By properly controlling bow thrusters, azimuthing propulsers, and other elements of a ship’s propulsion system, DP makes it possible for a ship to hold a given geographical location and required heading even under severe conditions. DP also contributes to operation quality and efficiency because waypoints can be used to minimize time between stations and heading and ship track can be controlled accurately over long distances. The maneuvering and propulsion system is linked to the ship’s navigation system to ensure the position is fixed. DP systems installed retroactively on vessels sometimes have inadequate propulsion and computer systems to maintain station in high sea states. Newer systems utilize onboard computers to control the machinery. Nine University-National Oceanographic Laboratory System (UNOLS) vessels currently have DP systems (all Global and Ocean class, the Intermediate Seward Johnson, and the Regional/Coastal Hugh R. Sharp). Of these, Knorr and Melville had systems installed retroactively, and Revelle, Atlantis, Thompson, and Marcus Langseth have had replacement systems installed (Annette DeSilva, personal communication, 2009). With the growth of offboard vehicles and the need to safely deploy and recover these systems, it is expected that DP will become a standard feature of research vessels rather than a special case. The Navy’s systems specifications for the planned Ocean class vessels explicitly states that a DP must be installed (Naval Sea Systems Command, 2009).

ALOFT SYSTEMS

Aloft systems include instruments such as meteorological sensors, GPS and communications antennas, and instruments for measuring ocean surface reflectance. At present the upper portions of research vessels are not designed so that all aloft systems have the appropriate exposure; rather, they compete for space in a crowded part of the vessel and performance is compromised. The vessel requirements for GPS and communications systems, for example, concern clear sight lines between the antennas and the required satellites in any possible position, from overhead to the horizon in any direction. In current installations, the antennas



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