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

Figure 6-4. HSM Pattern
C. To attract survivor attention, a vessel should periodically
make heavy black smoke, rotate a searchlight beam around the horizon
during night time, or turn on deck lights. Periodic sound signals can
help when searching for survivors under raft canopies. Crew members
should be alert for signals from survivors and other signs, such as
floating wreckage or objects, indicating their presence. At night or
when visibility is seriously restricted, the engines, if feasible, may
be stopped periodically and a listening watch maintained for survivor
signals.
D. When executing search patterns, every SRU normally begins its
turn from one searchleg to the next before actually reaching the end of
the searchleg. A marine SRU should begin its turn, as shown in Figure
6-6, short of the end of each searchleg by a distance equal to the
"advance" of the craft for the search speed and amount of rudder used
entering the turn. The craft will begin the straightaway portion of the
next leg--upon completion of its 90 degree turn--by a distance equal to
the "transfer" of the craft for the search speed and rudder used
entering the turn. Figure 6-7 depicts a typical vessel-turning circle,
with the advance and transfer distances indicated. SRUs from some
countries (e.g., Canada), execute turns outside the search area.
644 Inland Search
Information unique to inland search is presented in Chapter 8.
6-8