What a crummy post. To clarify:
692 ships of the US Navy in WWII
5000 allied merchant ships in WWI
5000 allied merchant ships in WWII
And then pure poppycock guessing after that equals approximately 20,000.
Any clue how long a wooden hulled ship is recognizable at the bottom of the sea?
A 2500 year old greek trading vessel was recently found on the bottom of the med. I read about it in the wine spectator; unfortunately they didn’t dwell on the ship itself, but apparently, it was still recognizable as a ship (maybe just the keel was visible). The wine, stored in clay vessels, was still drinkable, although it had lost some of its fruit. The spectator gave it an 88 
My one book on shipwrecks lists 1369 wrecks of interest in the last 400 years. It focuses on ships that were carrying large amounts of money, so this number should be regarded as extremely conservative.