I used to think that cruise ships had an unlimited supply of tenders to shuttle passengers back and forth to ports - or at least, if not unlimited - limited only by the supply of full-sized life boats. On our last cruise (Crown Princess) the bridge tried to "manage expectations" by warning passengers that due to the distance from moorage to the port in the Falklands - and the limited number of tenders, some passengers might not get to disembark (or words to that effect). Turns out - there was no problem - everyone who wanted to go ashore got ashore. Also turns out  that the number of life boats (under international law) that can be used for tendering is strictly limited, must be identified as tenders, and that the rest can ONLY be used for emergencies.