Drop video is used mainly when you have deep or contaminated water and a pretty good idea where to look. A video camera is placed in an underwater housing that's equipped with lights and a 100 - 300 foot cable that leads to a surface video monitor. The tender simply lowers the camera over the side of the boat until the camera is a few feet off the bottom (the distance depends on visibility), while someone watches the monitor. The tender moves the camera around the boat or platform, being careful not to hit bottom, or the boat is moved slowly. If the objective is spotted, one method of marking the location is to cut the power to the camera (so as not to blow the bulbs on the lighting system) and lower it to the bottom beside the objective. Divers then simply follow the camera's cable down to the objective. Whatever way you decide to search with drop video, it should be practiced before you need to use it on an operation. Drop video usually costs from $500 to $6,000.
The picture to the right is a DV-1 Drop Video System by JW Fisher. For more information: