Self-Locating Datum Marker Buoy

Conducting Search and Rescue (SAR) operations is one of the missions of the U.S. Coast Guard. Given a last known position (LKP) or estimated initial position (EIP), accurate estimates of the sea surface currents in the vicinity of those positions are critical to provide accurate estimates of the drift of the survivors or survivor's craft away from the LKP or EIP at the time of searches. A self- locating datum marker buoy (SLDMB) is an efficient method to obtain sea surface currents in the vicinity of an LKP or EIP during a SAR case either to provide data directly to the Coast Guard's Search and Rescue Optimal Planning System (SAROPS) or to assess the quality of various sea surface current products available to SAROPS by comparing drift of the SLDMB to their simulated drift in SAROPS. Self-Locating Datum Marker Buoys are oceanographic drifters that continually transmit their position and other environmental data in support of SAR missions. They are also used to mark the location of objects in the water. SLDMBs are carried onboard and must be safely deployed from both surface and air assets. They are deployed in heavy/inclement weather conditions and in both salt and fresh water. SLDMBs are frequently deployed in harsh weather conditions (e.g.: high winds and waves, storm and icing conditions, etc.). There are restrictions on the size, weight, ease of use, and reliability of SLDMBs to support these deployment environments. Oceanographically, SLDMBs must drift with the upper one meter of the ocean, minimizing slippage with the water and rectification of the wave motions. They operate on the open oceans and the Great Lakes.