The waters are full of crap that has been discarded, just stopping to check each piece could take awhile. Once flotsam gets waterlogged, it goes beneath the surface a ways, hard to spot from a ship. If it did crash into the ocean, it will be an aircraft search that finds it. Especially in the case of a cataclysmic event at altitude.
Thank you. Didn’t consider that the waters could be massively polluted with trash already... But considering where it is we’re talking about it would make sense that it is.