that should be the time you will get back to the ship. unless there is a major reason if you are on a ship's excursion and it is late getting back the ship should wait for you.
on one cruise we took in Panama the excursion we took was to go on the canal to the Pacific, then board a bus back to the ship, we did not even get off the ferry until after the ship was to have left and by the time we got back we were 3 hours over time, but the ship was still there, of course there were 300 of us from the ship on that and I am sure that it happend a lot.
at another port the tour bus was stuck behind an accident on the road that was taking a long time clearing so the ship had the tour opperator send another bus and then the passengers walked around the accident and boarded the new bus and then back to the ship, we were an hour late leaving .
Star Princess 2005, Sun Princess 2005
Caribbean Princess 2006, MSC Lirica 2006 , NCL Pearl 2007, Majesty of the Seas 2008, Carnival Destiny 2008, MSC Lirica 2009, Carnival Valor 2009,Carnival Legend 2010, Carnival Liberty 2010,Carnival Fantsay 2011,Carnival Valor Feb 2012, MSC Poesia Dec 2012, MSC Poesia April 2013, Carnival Legend Nov 2013, MSC DIVINA Jan 2014