The only place I've ever seen Sub-Mariner is in the old Avengers beat-'em-up arcade game. Just before you dive into the water for a goofy shooting level, you run past him and hear someone yell, "Thanks, Sub-Mariner!" I guess he was the one supplying the vehicles for the characters who couldn't use their superpowers in the water.
By the way, Karl, were you referencing that game in the title of the article? It reminds me of the way the game's cheesy narrator voice would yell, "America still needs your help!" when you died.