During the Second World War medical transports at sea made wide
use of radiocommunications to signal their identity and indicate their position
and route. Today such means of identification for protected transports (hospital
ships, rescue craft and medical aircraft) are even more effective.
When sailing through a dangerous area, e.g. where naval
operations could take place, a hospital ship could send out a blind transmission
on the appropriate frequency to provide identification, giving its call sign
(which provides information on its nationality), its name, position, destination
and route, in accordance with the International Telecommunication Union's Radio
Regulations.11 For obvious reasons of security, no answer would be
transmitted by ships involved in military operations.
11Radio Regulations, Arts 40 and
N40, International Telecommunication Union,