Several former Marines said that the ways the aging AAVs are designed and operated make it 'tough' to get a full load of Marines out in a crisis. If it sinks, troops in heavy combat gear have to hold their breath and climb out of a flooded vehicle through narrow, hard-to-open hatches. The escape plans for the often overcrowded vehicles appear problematic at best and at worst, disasters waiting to happen.
AAVs rarely sink and fatal mishaps are uncommon for the 26-ton tracked vehicles made to move Marines from warships at sea to shore under fire, but tragedy struck in late July when an amphibious vehicle sank rapidly to a depth of 385 feet off the coast of southern California during a training exercise.
An opening in the deck of a boat or ship.
The water pressure on the outer hatch is always greater than the air pressure inside the submarine.