In multiple forms of media, most notably the Assassin’s Creed game series I’ve seen an odd kind of sailing vessel; its main feature is that it uses its massive battering ram on the prow to attack. Did any such ships really exist, to be designed for slamming into enemy ships? If so, how did the ships minimize the damage to themselves?
I'm not familiar with AC, but are you thinking of a vessel that looks something like this? I believe one of the AC games takes place in the first century BC, which is when that type of ship (a trireme) was common in the Greek world. Triremes and other types of similar vessels, generally lumped together as "galleys," did attack one another by ramming.
If you take a look at that photo (which is of the modern-day Greek galley Olympias), one thing you'll notice is that its bow has a purpose-built ram on it, made from bronze. Clearer picture here. The ram bow was copied from one in the Piraeus archaeological museum, and you can see from that second image that it integrates closely into the structure of the hull -- both the keel of the ship and the strakes on either side of the bottom hull, not to mention the beakhead, fit into the ram. So the whole force of the thrust is transmitted globally into the hull.
Ramming as a tactic is something I'm not as familiar with -- I may ask my colleague u/iphikrates to chime in on this -- but the basic idea is that if you punch a big hole in the side of another trireme at the waterline, the crew on the other ship is going to start having a bad day immediately. (The first rule of ships is to keep the water on the outside.)
Is that the kind of thing you're thinking about, or am I misinterpreting the question?
Depending on the period we're talking about, yes, sailing ships did slam into each other quite often. Arguably, for triremes that existed in the ancient Mediterranean, close quarters ramming was the primary method of causing damage to the enemy. The ships were equipped with a bronze battering ram that was used to cause the damage. The sides of the ships were wood, as were the rows of oars that stuck out the side, so if you were skillful enough and had a well trained crew, you could outmaneuver the enemy ship and hit them on the broadside, or sever their oars, causing havoc and potentially sinking them. The ships were also manned by marines who could board enemy ships and engage in hand to hand combat. The Romans in the First Punic War were known to arm their ships specifically for boarding action, in order to bring their superior infantry to bear against the Carthaginians, who were a lot more experienced in traditional combat.
The tactics of ramming were still considered a part of naval doctrine all the way through history, even in WWII. As firepower from cannons improved, approaching the enemy at close quarters became unfeasible for first rate ships of the line, but against submarines it was still effective, and there are scores of successful rams by destroyers and even merchant ships against submarines during WWII.
