You don’t give any background on this, if it’s a real incident. If it’s theoretical, you have too much time on your hands.
Sea water is salty and will probably corrode anything. Any water on a condenser mic is likely to cause problems … especially if phantom power is involved. As I understand it, strong spit can damage or inhibit a capsule. This is part of the reason for using pop filters - not just to prevent plosives - but to protect the mic from excess moisture and spit. I’m sure there is something that is used to work around this, at least when using boom mics with windscreens/zeppelins. They would probably shield the mic. Even on the “high seas”.
I can’t help but getting the sense of a “Jackass” type event going on behind this. Please expand.