^ I'm sure, since Namor's matched/beaten Hulk underwater. There's analysis of Namor's bouts with Hercules, and I recall at least one instance where Namor was dominating Hercules underwater, then wished only to be hydrated and matched him thereafter.
I'm talking just strength, naturally Namor will have the edge in the water due to his huge mobility advantage. But in strength for strength I seem to recall Hercules outdoing Namor in the depths.
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The price of fame is high and the Thing cant pay the way.
Hercules managed to push against a force while Namor couldn't once. I still think that came at a time where Namor was constantly morose and doubting himself though. He went through one of those phases around that time. And I'm confident it was the "gift" of battle that actually got him out of his funk.
But Hercules has never beat Namor in a fight underwater. Namor was straight-up beating him once. Matched him a few times thereafter underwater, all while proclaiming his strength underwater couldn't be matched by Herc, and Herc basically doing nothing to overturn that proclamation.