Honestly, would you consider this a primary means of attack? Consider the effects on the hull of your vessel and its contents. Consider poor Cookie, down there in the galley, suddenly impacted with whatever victuals were to be served in the mess. Coal tenders suddenly under tons of antracite. Gunners faced with their arms still moving in the direction of travel while the rest of the ship has stopped, or has recoiled backwards. Scenes in the engine room.... If a ship has enough way to build up the momentum to attempt the lunacy of ramming then other more viable options might be open to the commander.
Has anyone ever found the ram that was fitted to the CSS Virginia? She lost that piece and no one knew it was gone for days after the attack.