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Marine Rescue Dive Unit

The King County Sheriff’s Office Marine Rescue Dive Unit (MRDU) deploys specially trained and equipped Deputies that are responsible for water-related law enforcement, investigations, rescue and recovery work.

Operational areas include Puget Sound, Lake Washington, Lake Sammamish and other lakes, ponds and rivers throughout the unincorporated areas of King County, cities / towns that contract for service and any other jurisdiction that requests specific assistance.

Services include:

  • Patrol of waterways 
  • Evidence search / recovery
  • Emergency response and rescue
  • Swiftwater, Flood and Ice rescue
  • Firefighting and dewatering
  • SCUBA diving
  • Accident investigation / reconstruction
  • River large wood mitigation investigations
  • Safety inspections
  • Buoy placement and maintenance
  • Derelict vessel investigations
  • Boater and water safety education
  • Victim recovery and investigation
  • Maritime Security Operations
  • Hazard removal
  • Spill response and containment
  • Investigation and removal of vessels dumped on public land
  • Helicopter deployment - Hoist and Diver insertion

Public safety SCUBA diving

Deputies are trained and equipped public safety SCUBA divers that primarily dive in cold waters with little to no visibility, including moving water (rivers). Deputies receive specialized training in underwater evidence searches and evidence, victim and vehicle recoveries. Deputies utilize underwater cameras, metal detectors and a remotely operated underwater vehicle (ROV) equipped with sonar, video and a gabber jaw. Divers can be deployed by helicopter into remote and hard to reach areas.

Swiftwater, flood and ice rescue

Deputies are trained and equipped in swiftwater, flood and ice rescue and recovery operations. Deputies utilize special equipment to conduct rescues and recoveries in and around rivers, flooded areas and frozen bodies of water.  Deputies can be lowered by helicopter hoist into remote and hard to reach areas.

Vessel operations

Deputies are trained in emergency vessel operations.  The MRDU operates vessels of various types, capabilities and sizes that allow deployment on bodies of water almost anywhere (including by helicopter) when needed. Deputies drive specially equipped 4x4 trucks to aid in reaching remote areas, tow various vessels and carry a wide assortment of rescue equipment. 

Accidents and reporting

A boater who is involved in an accident must stop his or her vessel immediately at the scene of the accident and assist injured people or anyone in danger unless doing so would endanger his or her own vessel or passengers.

Washington State law requires the operator of a recreational vessel involved in an accident to file a Washington Boat Accident Report when:
•  Loss of life occurs
•  Injury occurs which requires medical treatment beyond first aid
•  A person disappears from a vessel under circumstances that indicate death or injury
•  Property damage is in excess of $2,000 or there is complete loss of a vessel

If there is an injury, disappearance or death, a report must be submitted within 48 hours. Reports in other accidents must be submitted within 10 days. If the operator cannot submit the report, the owner of the vessel is responsible.

The law enforcement agency of jurisdiction is required to investigate and submit a Boating Accident Investigation Report (BAIR) whenever the accident results in:
•  Injury requiring hospitalization
•  Death

A vessel is defined as every description of watercraft on the water used or capable of being used as a means of transportation on the water.

The United States Coast Guard does not investigate or report recreational boating accidents.

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