well predatorv2 said.
"As for the cloaking: the cloaking field which I believe is built right into the predator armor creating a closed circut, which is why when the predator interacts with it's environment the cloaking field stays contained to the predator itself. The cloaking field works by bending light creating a 'invisible mirror' effect.
Water is much more dense than air, the field cannot be completed because the water interferes with the connections between the armor/suit, that is why when the predator from the first pred movie got out of the water his cloaking field did not just shut down, it crackled, sparked and tried to re-establish the circut."is that enough proof.