I know it's not WWII, but I'm hoping some of the knowledgeable folks might be able to identify this. It's captioned "American sailors during a joint exercise by the militaries of the United States and South Korea off the coast of Pohang, South Korea, in 2017." It appears to be a hovercraft, and I'm thinking it might be US Army; they have a substantial amphibious force. Maybe something new or experimental? Thanks for your help!