As long as its dried it will be fine. Lots of old growth flooring is being pulled up from rivers in the US and sold for big dollars. Loggers used to float the logs down the rivers to the mills, some of them sank and are being reclaimed after a couple decades.

A couple of days in the ocean wont hurt that lumber at all.

Sticker and stack it and weigh it down so it doesnt warp when it dries.