This is part IV of a four-part series on AAVs. You can read part I here, part II here, and part III here.

I return to the AAV that sunk in July and the question that prompted me to write this: What caused the sinking? Was it a human or mechanical error, or the condition of the sea? The retired Master Sergeant I spoke with, my former fellow platoon commander at 2nd AA Bn, had some theories: “Too much pressure from water on the plenums. Bad plenum seal, etc.” In the comments section of one article about the incident, a user named DevilDog47 claimed that the Sailor got a top hatch open, but the sea levels were so bad, a wave smashed it back down and crushed him. How did he know? Was he there? Could he be a Marine who watched from a nearby amtrack? 

As for me, I think back to an eyewitness account saying that the AAV “rapidly sank.” From my experience in amtracks, I can only assume that there was a major failure in the vehicle’s watertight integrity for it to go down so quickly. Normally, an AAV taking on water would at least allow enough time for the crew and passengers to evacuate. As multiple commentators have written in the comments sections of articles about this mishap, it’s likely that the culprit was the plenums. This is a cavernous section at the front of an AAV, so big that, when open, it could fit a sleeping Marine. When it is filled with water, the AAV takes a front-loaded nosedive into the ocean.

I don’t question the safety of the AAV. I rode in them in the water many times without incident. Although the bulk of my time in the Marines was spent in MRAPs and in the desert, I knew other officers and enlisted Marines who operated AAVs with hardly a single mishap. It’s not their safety that concerns me so much as their usefulness. I spoke to an Air Force officer about the future of amphibious war. He made a point: there is a certain nostalgia surrounding amphibious operations by generals who cut their teeth on amphibious operations. Marines take blitzkrieg to heart.