colussus doesn't need to breathe when armoured so it wouldn't really matter too much if he were thrown underwater
colossus can't catch spidey and spidey'd have a hell of a time trying to hurt C-boy, he could maybe try battering him with a steel girder, but i doubt that'd KO him anytime soon
spidey'd throw colossus all over the place,try to electricute him, smack him t=with stuff, web him up and if none of that worked he may go retreat to find some kind of acid or something........ maybe wrap him in steel cable, plug him into a generator and make him into an electromagnet which, i think, would make him unable to move.......... though i could be wrong
colossus' own fighting technique is at least equal to that of spidermans, spidey is a scientific genius, not a tactical one, there is a difference (if i had a penny everytime i...), colossus is just as accustomed to battle as spidey, if spidey keeps his distance this is a no fight... but if colossus gets his hands on him its bye bye spidey...
its like saying the same about bruce banner, he's not a battlefield genius, there are completely different criteria that make up battlefield and scientific genius... thats why cap and cyclops are good leaders but probably only barely passed science class... i dont doubt spideys intelligence, i just dont believe its enough of a factor...