Here's what the Steam page says about the game and the reality:

Steam: "recreates the legendary sea battle"
Reality: It does not recreate the battle of Trafalgar, which was a naval battle between on one side, 27 ships and on the other 33. Here in this game you have 15 ships vs. 15. Well in fact I say 15 ships on each side, but that's because you can only have 15 ships max on each side at a time, so when some ships are sunk, and only then, you suddenly get "reinforcements" turning up to make your total 15 again. Even so, there are only 25 ships on each side anyway. The fact that the ships turn up when you lose other ships make it feel like an arcade game with "lives" not a historical simulation.

Steam: "Historically accurate ships from all three Navies"
Reality: No. They are not historically accurate at all. For example the Santissima Trinidad had 112 guns, the Victory had 100. In this game there are only two different ship models in the whole game and the big ones all have 90 guns and the smaller ones have 46. They even stupidly decided to give the Santissima Trinidad 46 instead of 90, which would at least have been closer to its real total. Saying the ships are "historically accurate" is nothing less than a lie.

Steam: "Real-world naval strategy of the era accurately recreated in the battle AI".
Reality: No evidence of this at all. The AI is dumber than a bag of wet mice. As for your own ships there are severely limited options for controlling them so most of the time you feel like the game is just playing itself.

Other disappointing things: In the screenshots of East India Company you can see sailors doing stuff on deck, so I assumed there would be visible men on decks in this add-on too. Not so. Despite actually having an option in the menu dedicated to how detailed you want crew to be, there are none.

The cannon fire in a stupidly unrealistic firing arc too and reload about three times faster than on a real ship, with seemingly infinite ammunition.

I know this is in the end a video game but it's also supposed to be a historical simulation. After all, I was playing it on "simulation" realism. God knows what happens on "arcade"- you probably get nyan cat lasers or something.

So in the end, we have a poor arcade style game where you control a fleet of 15 ships against the enemy's 15 ships. They are all either "90 gun" ship or "46 gun" ship and when they get sunk, more turn up, from a total pool of 25 ships. The ships have the same names as some of the ships that fought in Trafalgar!

Abysmal.