The Royal Navy repeatedly changed the identifying numbers carried by its motor torpedo boats to confuse observers about how many craft were operating. The deception could also create administrative uncertainty because allies and even British personnel might struggle to follow the renumbering. A cheap visual change therefore supported operational security without altering the boats themselves.
Notable Point · 49:17-50:25
How changing MTB numbers obscured British strength
Frequent changes to Royal Navy motor-torpedo-boat numbers made the force appear more numerous and complicated identification even for allies and British personnel.