a) priority to Ship’s Shore Excursion passengers. Replace w/ K 16
     b) all others: may be based on …: 
         1) # of peeps & how late, 
         2) how far away (in time), 
         3) wait costs ( dock fees & fuel), 
         4) next port arrival schedule, 
         5) weather etc,
         6) tug/harbor pilot availability.