[swaghauler]

Don't forget the "surge" from the airburst. It could easily be 50m high in the shallows depending on the depth of the water and the altitude of the airburst (if it was over water).

All US ships have been EMP shielded since the 80's and 10km is a bit of a reach for the incendiary blast from a 2KT airburst (which would extend about 3km). However, having the hatches open through the blast (which wouldn't directly reach the ship as a 2KT blast would generally only reach about 5km) could cause uncontrolled flooding. This in combination with a large surge (more common in shallow water rather than deep water) could swamp/capsize the ship.

The flash would extend to the horizon and could blind at 10km because it is an airburst (at probably 500 meters of altitude to maximize the blast).

Ok, I see you're talking about 2 MEGATONS (X2 the largest single warhead the Russians used)!

The Blast Effect would cause Minor structural damage to the ship (it will "toss" 150,000 lb railroad cars around at 5km).
The Incendiary Effect would possibly set fire to all flammable materials (including uniforms) and anodized aluminum would most likely lose its structural integrity (this can happen at just 250 degrees F).
The Radiation Effects would be fallout only.
The Surge could easily top 100 meters and would probably damage the ship (if the airburst was over water).

Also, keep in mind that if you're talking about multiple explosions which equal 2MT, things change. Wave Propagation occurs (and will be wider and taller) and Blast Range can be "amplified" by the intermingling blasts of multiple detonations. Incendiary Range would be reduced by the interaction of multiple blasts, though.