Page 579 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

578 CHAPTER 21 Practical Applications
while enhancing the chance of success. With the right equipment, in properly trained hands, good results can be obtained with the ROV in the dive team’s tool chest. This chapter will explore the basics of finding, documenting, and recovering items of interest to the PSD through the use of electronic search techniques.
21.3.1 Public safety diving defined
“Public safety diving” is normally defined as diving operations by or under the control of a gov- ernmental agency for the service of the general public. This covers all aspects of search, rescue, recovery, criminal investigations, and any other functions normally covered by police depart- ments, fire departments, and other applicable governmental agencies. Examples of public safety diving would be crime work done by the federal, state, and local law enforcement agencies, search and rescue missions performed by police/fire departments, and disaster relief operations. Examples of operations excluded from this definition would be commercial inspections of public sewer outflows, inspection of bridge abutments, and other services not in the direct service of the general public.
21.3.2 Mission objectives and finding items underwater with the ROV
ROVs are a supplement to the PSD’s tool chest. Under current technologies, ROVs are becoming much more useful and pertinent to the PSD team’s operational mission, providing an enhancement to its capabilities. The function of the ROV in this long chess game of finding items of interest underwater is in the endgame as a final identification tool. The ROV has limited search and some recovery capabilities. The main function of the ROV is to lower the physical risk to the PSD by putting the machine at risk in situations and environments that have been traditionally borne by the PSD.
The PSD’s objectives in performing an underwater search follow:
• The isolation, securing, and defining of the search area
• The clearing of the search area of possible targets
• (Upon location of the items of interest) the gleaning of what information from the site is
available, to department standards of documentation
• The disposal of the item as deemed necessary by the command structure
The actual search technique for locating bottom targets with an ROV system is to run the search pattern across the bottom as high off the bottom as possible, based upon the water visibility, while maintaining visual contact with the bottom. The search is run either with a single camera display (which most OCROV systems possess) performing a zigzag pattern across the bottom along the search line (to search on either side of the submersible) or in a straight line with multiple cameras providing wider camera coverage. It is imperative to keep visual contact with the bottom at all times while transiting the coverage area, if for no other reason than to raise the possibility of a “lucky find.” So-called spaghetti searches (unstructured look-around searches within the search area) are quite popular in getting the immediate result of searching and performing a task, but