We're flashing back to the adventures of the Sub-Mariner as a youth, before he develops his power to fly and much of his super-strength..
He's been trapped atop a massive ice floe, with no open water for miles. How will he survive?!?
The playmates who stranded Namor finally 'fess up...
U-S-A!! U-S-A!! Woo hoo!!
(OK, no doubt Bill Everett was using "American" interchangeably for "human" here. Still, U-S-A!! U-S-A!!!!)
From Sub-Mariner Comics #35 (1954)