Some ships taken up from trade in the Falklands War lacked communications equipment suitable for exchanging the required instructions. The Royal Navy used helicopters to pass written messages to some of those ships. Small pieces of board carrying chalked instructions are the example given. The comparison warns against assuming that every merchant vessel had the same ability to communicate with a military force. It sets up the earlier shipping problem faced by planners trying to keep a carrier approach secret.
Notable Point · 24:35-25:15
Falklands merchant ships and improvised communications
The Falklands example illustrates why military control of merchant shipping could require improvised ways of passing orders.