Originally Posted by avant
Under the current international code of signals, Lima does not have two meanings. Lima has nothing to do with quarantine unless local authorities request/require it to be flown.
signal is used to only request free pratique, whereas laying at quarantine requires the use of the Lima flag. Quarantine used to be 40 days, with Covid-19 the standard is 14 days.
For example: Reference to specific ordinances in Alaska
Bristol Bay notice: See flags
The plain yellow flag ("Quebec" or Q in international maritime signal flags), perhaps derives its letter symbol for its initial use in quarantine, but this flag in modern times indicates the opposite—a ship that declares itself free of quarantinable disease, and requests boarding and inspection
by Port State Control to allow the grant of "free pratique". Pratique is the license
given to a ship to enter port on assurance from the captain
to convince the authorities that she is free from contagious disease. The clearance granted is commonly referred to as free pratique. A ship can signal a request for pratique by flying a solid yellow square-shaped flag. This yellow flag is the Q flag in the set of international maritime signal flags
There is no request for clearance, or inspection
during the period of mandated quarantine, hence no use of the Q signal flag during that period, instead the Lima signal flag is flown for the duration of the requisite quarantine. The vessel remains in isolation, no free pratique is requested nor granted until after quarantine is successfully fulfilled and then if and only if, the ship has remained disease free can the vessel at that time request free pratique and initiate such by flying the Q flag to signal such. Only after successfully fulfilling quarantine, will the port authority provide for inspection and clearance proceedings.
Since flying the Q flag involves a request for boarding by Port State Control, it has also become an invitation to Customs
to inspect a vessel for dutiable goods or contraband.