That find is the epitome of what harbor patrol divers are used for — to clean up police scenes and bring closure to cases. It’s less search and rescue and more search and recovery, said the dive team sergeant, Steve Mitchell.
Once a month, the divers, the only police dive team in Orange County, suit up and head out to the ocean to fine-tune their craft.
It’s a mix of state-of-the-art technology and old-school tactics.
Technology
When it can, the dive team uses as little manpower as possible and relies on high-tech equipment.
A favorite among the divers is sonar. If possible, they use the sonar to see in about a 1,000-foot radius along the ocean floor. It blips out a signal that shows a “shadow” on their screen when it crosses something as small as a gun. In water deeper than 30 feet, the dive team will position its sonar unit below their boat. In shallower water, the sonar will actually show the surface of the water and clutter the screen, an unfortunate side effect of its precision, Mitchell said.
A mobile version of that technology is the ROV, or Remote Operated Vessel. The ROV is about the size of a car tire and comes equipped with a camera, small motors and its own sonar. It swims deeper than the divers do — their limit is about 100 feet — and can scout out potential dangers or difficulties for the team. Its only drawback is that with the center of the sonar screen consistently moving, it’s difficult for divers to pinpoint their target.
To communicate, the harbor patrol uses the Aquacom STX 101 and STX 101M, basically a radio in a suitcase. The radio helps crew members on board talk to the divers while they search. When they use it in combination with the sonar, the men on board can guide divers to their target within a foot.
