If he used his true strength, he'd be unstoppable.

Has survived a point blank nuke but implodes if touching water

Real af

I think that it's because his suit is very heavy thus he cannot swim. Also he probably has vents everywhere on that armor, gotta breath some way.

Fr

bro can survive space and a tiny bit of water gets bro tweaking.

But not in Halo 3!

yuh

I loved going under the Halo 3 water and shooting the fishies under water.

When one centimeter of him suit touches water:

He can't sprint for more than 4 seconds without needing a break.

I think it's his armor. It probably weighs a lot.

It's about 50 lbs, but for a Spartan II, that should be no problem since even Noble 6 could easily lift over 50 lbs.

Crap your right! Um... Maybe it's his weaponry?

Even somebody in today's modern military could most likely carry MC's traditional weaponry, and normal Spartans are like Super-Soldiers, and MC is a Spartan II, which would be like a Super-Duper-Soldier.

WAIT! Maybe it's for stealth! Enemies won't notice him if he approaches under water! Maybe THAT'S why he sinks like a brick!

Yeah, but he himself would still sink without much armor, I'd bet.

OH! It's himself that makes him sink! HE is what weighs him down in water!