I don't think it would do all that much damage, considering the generally large contact areas and relatively low speeds of the ships outweigh the mass increase from the projectiles that are shot. The best one could hope for with ramming I think would be to knock a ship's aim off for a few seconds
You'd think, but imagine a WW2 battleship crashing into the side of another WW2 battleship.
Sure, those big guns do a lot of damage if a ship went bow on into the side of another one it would probably end it.
Also, I think there were ships intentionally built to ram ships in one of the ancient greek versus persian wars. How fast were those boats going? We're talking about oar driven boats with brass tipped rams.
So speed doesn't matter much if you've got a lot of mass behind it.
I'd keep the idea only because it would be interesting.