Maritime SAR Drift & Search Area Planner
Compute maritime datum positions from Last Known Position (LKP) using Total Water Current (TWC) and wind-induced Leeway divergence. Generate optimal Expanding Square (SS) search patterns and export GPS coordinate grids for rescue vessels and aircraft.
Tactical Situation Plot & Vector Diagram
Navigational Waypoint Sequence (Expanding Square Pattern)
| WP# | Latitude | Longitude | Bearing | Leg Length |
|---|
Drift Physics & Vector Decomposition
TWC displacement: 8.40 NM @ 220°
Downwind axis: 290° (Wind from 110°)
Leeway speed: 0.33 kts (Displacement: 1.98 NM)
Divergence Left: 275° | Divergence Right: 305°
Confidence Envelope: 2-Sigma (95% containment)
Maritime Search & Rescue (IAMSAR) Principles
Standard operating doctrine developed jointly by the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO) for maritime datum and drift estimation.
Total Water Current (TWC)
TWC represents the physical movement of the water column carrying floating bodies. It incorporates tidal streams, ocean currents (e.g. Indonesian Throughflow, Gulf Stream), and longshore transport. TWC carries all objects at identical velocity regardless of their hull profile.
Displacement = TWC_Speed × Elapsed_HoursLeeway & Divergence Angle
Leeway is the motion of a floating object through the water caused by wind blowing against its exposed profile. Due to asymmetric hydrodynamic lift and asymmetrical windage, objects rarely drift purely downwind; they diverge left or right by up to 35°.
Leeway = Multiplier × Wind_Speed (kts)Expanding Square Search (SS)
The Expanding Square pattern is standard when the datum position is known with high accuracy (such as immediately after a capsizing distress call). The vessel starts at Datum, steered outward in 90° right-hand turns with legs expanding by track spacing S every two turns.
Legs: 1S, 1S, 2S, 2S, 3S, 3S, 4S, 4S...