everytime me and my brothers plays coop on any water based map like islands and team islands the game freezes about the time i get to tech level 3 for some reason, we get the Vote Screen where we can choose the wait continue and save and exit it will show save and exit for both of us on my screen but his screen shows i'm still on wait. is there a way to fix this? it happens all the time on these kinds of maps.

Sounds like something is going wrong with your connections rather than the game.
It'd be more likely that the game goes out of sync or crashes if it were at fault.