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

652 Diverting Vessels
A. While merchant ships have a moral obligation to assist those in
distress, they are not generally suited for extensive searching. The
master makes the final decision to proceed to the distress. The
responsibility international law imposes on masters to assist applies to
distress situations, and not to Uncertainty and Alert phases of SAR
missions. Vessel assistance should be requested by SAR authorities
rather than directed. The SMC or OSC should arrange for the ship
requiring assistance to communicate directly with other ships which seem
best able to assist. When a merchant ship is no longer needed, the SMC
or OSC should thank the vessel, in terms of "your assistance is no
longer needed" rather than "you are released."
B. SRU navigators should plot the position, course, and speed of
all vessels sighted during a search and the vessels listed in the AMVER
SURPIC. If survivors are sighted, or the distress scene is located, the
nearest vessel can then be quickly determined. The following methods
may be useful in the effort to divert a vessel:
1. A radio message to the vessel giving survivor position, and
requesting the vessel to divert to assist. If unsure of the
frequency guarded by the vessel, contact should be first
attempted on channel 16 VHF-FM, then 2182 kHz.
2. A homing signal transmitted on 522 kHz, 410 kHz, 500 kHz, or
other frequency allowing the vessel to obtain a DF bearing.
3. A message block airdropped to the vessel, giving survivor
position(s), and requesting assistance.
4. A pyrotechnic flare signal fired.
5. The vessel circled at least once at low altitude, then the bow
crossed while rocking wings, opening and closing throttles, or
changing propeller pitch, followed by flying in the direction
of the distress, repeated until the vessel follows, or
indicates it is unable to comply by hoisting the international
flag "November" (a
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