A really big boat

I was riding in a big boat.  The boat was so big I could look down on all the other boats.  They looked like rowboats compared to this boat.  The boat had two engines.  A normal one plus a large outboards engine.  We got the boat going really fast then started up the outboard and the boat doubled in speed.  Just ahead of the boat was a small island with a rocky shoal.  We had to swerve at the last second to not hit the shoals.