charlie reminds me of one more people need to know..
When securing the boat to a mooring - you use two lines and two cleats.  On a mono, it should be pretty obvious which two cleats - there the only ones at the bow!
On a Cat, apparently it is not obvious.  You use the two cleats on the BOW - the spreader (not sure of its proper name) that connects to two bows has cleats - thats what you use.  NOT the cleats on the port and starboard side of the hulls.  I've seen lots of boats hooked up that way our past few trips.