Running a simple simulation:
"""
model VesselSim
  import SI = Modelica.SIunits;
  constant SI.Position Smax = 3125. "Travel distance";
  constant SI.Mass mass = 1939 * 1024 "Vessel mass";
  SI.Velocity speed(start=0.0) "Vessel speed";
  SI.Position position(start=0.0) "Vessel position";
equation
  mass*der(speed) = 70000. - 65000.;
  der(position) = speed;
  when position >= Smax then
    terminate("Simulation reached end of travel");
  end when;
  annotation(experiment(StartTime = 0.0, StopTime = 3600.0, Tolerance = 1e-06));
end VesselSim;
"""

The simulation runs OK exept it fails to terminate in the when condition. This simulation was
also run on Dymola 7.4 and behaved as expected.

Runar