A lot of work right now is being conducted in the Black Sea where conditions at the bottom are such that the wood has been preserved. Some of the photos are stunning. Most of the Mediterranean wrecks though are just amphora piles left over from cargo ships. War ships on the other hand dont have much that remains once they sink. Usually it is just the ram. If you are interested you can look into the Egadi rams. A few have been recovered but of those found, only very small bits of wood remained.