The unit is capable of rescuing victims, recovering bodies and evidence, and enforcing the laws concerning the city's harbor area, which includes one of the largest deep water ports in the country, extensive recreational facilities, and an airport nearby. The team aims to establish a response time of 15 minutes -- fast enough to save drowning victims in the icy waters -- and to maintain the capability of effectively working with other teams in the event of a harbor disaster. Team members are involved in regular police duties until called upon, and their equipment is stored aboard a patrol boat which is regularly manned for harbor patrol by one team member. Members make at least one dive a week in a different part of the harbor and Charles River to sharpen their skills and familiarize themselves with the areas under the department's jurisdiction. It is hoped that this familiarity will result in a high success rate in locating evidence. In addition, the dives take place under all conditions and weather, and zero-visibility and night dives are included. A practice dive near the Brewster Islands in which team members searched for mock drowning victims is described. Photographs are provided.