1. Fortifications were improved and a new system of visual signalling introduced. 2. At this time her pennant number was changed to I72 for visual signalling purposes. 3. At this time her pennant number was changed to I77 for visual signalling purposes. 4. Visual signalling posts and relay posts for runners were prepared and messenger-pigeons taken forward.5. Visual signalling still failed again during the attack, due to mist, dust and smoke.6. At the end of May her pennant number was changed to I76 for visual signalling purposes. 7. visual signalling . this is limited by line of sight and visibility, which may be poor.8. In open warfare, visual signalling ( employing signal flags and the heliograph ) was the norm. 9. The primary types of visual signalling were Semaphore flags, lamps and flags, lamps and lights, and the heliograph. 10. They had also to learn visual signalling , first aid and artificial respiration, and pass a swimming test, covering fully clothed.
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