Re: That's what I'm more worried about.
You don't need a suitcase either - a simple shipping container will do in any port city you need.
More viable than a suitcase, for certain.
And I don't know how much of an effect such a shot would have. It would definately take out the port - but the effect would be very limited. Since it will be at Sea level, the blast will be largely dissapated up, the radiation (including heat) will be concentrated closely, and absorbed.
I suppose I'm thinking in terms of Charleston, SC and the like.. hitting NY with something like that would expose (I think) a lot of the towers/skyscrapers to the blast... How effective that would be is still a question, but it would be far more effective in cities with high-rises next to the port than those ports without...
I'd think you'd have a mile or so area of total destruction at ground zero, all the ships would be sunk... Depends on the target/attempt. I don't know what the effect of the container/ship around it would have, either... sure, its an atomic explosion, but that's got to soak up a lot of the get-going power to vaporize it.
Addison
