>>63878585
>>63878895
Another thing to consider: We don't really have professional, especially trained Marines until the Romans, and those guys just worse what legionaries wore, and they didn't find it a big super big problem. Landing Troops would have just been regular soldiers riding around on ships. A lot of them could hopefully swim, but you really aren't opting to go into the water if you can help it, and you certainly aren't going for a long swim with your arms anyway-- a shield and a long spear are pretty out of the question, so any swims would have probably just been as an expedient measure in unusual circumstances
We don't have too many narratives of Greek naval commanders describing battles in detail the way we have guys like Xenethon describing the minutiae and events of land battles, but we do have some mentions of guys who were also admirals mentioning their fancy bronze breastplates and stuff from time to time, so I think they probably wore them during intense ship-to-ship action.