[MizSterious]

They might be targeting cruise ships (actually, hotels on barges), but if they wanted to make a really big score, I'd lay bets on container ships loaded with explosives possibly laced with poisonous chemicals that would survive blasts. Harbors that would be most attractive would be those that are at the center of cities, as opposed to being on the outskirts--NY might be attractive for that reason. Cruise ships, also, would not have the death toll numbers that other ships might bring.

[CyberAnt]

"Cruise ships, also, would not have the death toll numbers"

You're saying a cruise ship (possibly 2000) would NOT have a bigger death toll than other ships (crew of 50-100) - how do you figure that ..??