Were the drills required to be done monthly or were you conducting them more frequently based on your own judgment? Captains of the Navy ships that I served on had their own preferences to conduct some drills more frequently than other captains did. While I’m quite sure that they all met the minimum standards, most , if not all of them, would exceed the minimum requirements.
Most of my sea life I worked on oilfield service vessels, which were chartered to oil companies or oilfield service contractors. The policies of these companies were to conduct fire, man overboard, and abandon ship drills monthly.
SOLAS requires that boat drills be conducted any time that 25% or more of the crew has been replaced. On these types of ships changes of crew and charterer’s personnel on board were quite frequent.
I never served in any Navy. Do they, to your knowledge, require drills at any set frequency?