[Former Proud Canadian]

Age, take a DEEP breath. Is it possible? Yes. Is it practical? I don't think so. See my previous posts. Anybody sailing across the ocean on a yacht with a dirty bomb would be DEAD from the radiation long before they reach North America. If they had enough shielding to make it, the boat would be swamped. A fishing trawler? Sorry those boats are being watched and are intercepted when they reach the 200 mile limit. There is a domestic fishing industry that needs to be protected.

Ok. Can the authorities account for EVERY eventuality? Probably not. That's why the US is taking it to the terrs in Afghanistan and Iraq and soon to Syria and Iran.

[SauronOfMordor]

Anybody sailing across the ocean on a yacht with a dirty bomb would be DEAD from the radiation long before they reach North America. If they had enough shielding to make it, the boat would be swamped.

Water makes a decent radiation shield.

Toss it overboard with 400 feet of cable, and drag it along underneath the ship. When you get close to the US, have a small motorboat tow it to shore at some deserted stretch

And AlQ has demonstrated that they have a few people who don't mind dying.

[Age of Reason]

Age, take a DEEP breath. Is it possible? Yes. Is it practical? I don't think so. See my previous posts. Anybody sailing across the ocean on a yacht with a dirty bomb would be DEAD from the radiation long before they reach North America. If they had enough shielding to make it, the boat would be swamped.

They make some pretty big yachts.

Or they could freight it across in severl trips, or tow a little bit at a time behaind the boat under the water, making several trips.

Or they could ship it across the ocean, transferring it to a smaller vessel in sheltered waters in the dark of night.

The smaller vessel wouldn't even have to take it aboard: it could be fastened beneath the vessel: when submerged, the stuff would weigh less, and perhaps the water would help to shield the radiation from detection.

I seem to remember that the rubber raft that blew the hole in the Cole, they said had the explosives under, and not in, the raft.