JP 3-50 National Search and Rescue Manual Vol I - US Navy

any source.
b. There is suspicion that a submersible has suffered a
casualty and requires assistance.
c. Air or power supply is known to be exhausted.
d. When it is overdue-fails to surface within 20 minutes
of scheduled surfacing time, or fails to make a scheduled
report, while submerged, within 20 minutes of the scheduled
reporting time.
442 Location of Incident
A. An accurate determination of the distress location is essential
for reducing search time. To have a good starting point for search
planning, the SMC should confirm the reported location.
B. If communications have been established with a distressed
craft, always assume they may be quickly lost. While still in contact,
the SMC should ask for position information. Immediate effect should be
made to resolve conflicting position reports. Whenever possible, the
SMC should obtain the data the craft used for plotting its position and
replot it.
1. Positions given in relation to uncharted or locally named
landmarks should be scrutinized. The SMC should make certain
that everyone involved is referring to the same object. Not
only are landmarks with names such as "Bird Rock" common to
many areas, but the same name may even be used for different
objects in the same areas.
2. Bearings and ranges should be plotted, and the distressed
craft's position confirmed by asking for other known
information about the area. If distances are estimated, for
objects beyond 4 nautical miles the tendency is to
underestimate and the greater the actual distance the larger
the error in estimation. {1}
3. Soundings should be acquired from marine craft to cross check
between reported and charted soundings.
4. On scene weather may help the SMC determine the incident
location. Useful weather information includes:
4-3