Doomed Costa Concordia cruised close to Giglio once before
http://www.gazzettadelsud.it/news/english/79417/Doomed-Costa-Concordia-cruised-close-to-Giglio-once-before.html
Court told that ships permitted to sail close if at slow speeds
the ships was traveling at 16 knots, which isnt slow, what if the ship was moving slow at say 2 knots, how different would it be?
Do cruise ships have underwater sensors?
What sort of sensors could they have, would they be effective?