5 Application: Efficiency of Search Plans for Lost Cargo
Consider the situation when the strong waves wash away cargo from vessel. The cargo is very
expensive and is not ensured. A crew d iscovers a loss of cargo after several minutes and decides to
rescue it; they send a helicopter or motorboat to mark lost containers with beacons. The helicopte r
flies along the main wave direction with a constant velocity until some container is spotted (seen
within a given range due to fog or rain). When the helicopter reaches container it will be considered
rescued and helicopter continues the search for another closest visible one or continues to travel along
the main wave direction. See Figure 4.
Initial simulation of trajectory of each container is performed for solid body that meets the ISO
standards for containers. They are colliding and are affected waves. Achieved results are used for
rescue operation simulation. We ran this scenario with given containers' trajectories with various delay
between cargo loss and start of rescue operation, helicopter’s velocities and visibility range. The
number o f rescued containers and rescue time (limited to 40 minutes) are shown on Figure 5. The plot
shows us that high velocity and large visibility range does not guarantee cargo rescue because greedy
algorithm can run into wrong decision that is critical for Travelling Sailsman Problem. It happens
since the distance between each container changes in time (as shown on Figure 2 and Figure 3). There
is no another option, since we don't know exact configuration of the network