Submarine visibility tables varied the distance at which ships and destroyers could be seen through a periscope according to sea state and the proximity of the enemy. The model forced officers to consider how long and how high a periscope could safely be exposed. Aircraft calculations began with 90 percent serviceability, fell to 80 percent on the second day, and used 70 percent thereafter during sustained operations. Worked examples converted those percentages into the number of floatplanes that could remain continuously aloft. Reconnaissance depended on equipment availability, observation conditions, and endurance.
Chapter · 22:05-24:13
Periscope visibility and serviceability constrained reconnaissance
The rules treated submarine sighting distance and the declining serviceability of aircraft as operational limits rather than abstract background details.