The biggest restriction, as always, is available art. I'm not sure if there is enough cultural variation available to support two different versions of the marine. Also, I'm not convinced there needs to be an 'old' marine; rather, the current Marine could be instead be modified to better represent a modern marine. This would would be the best match with both the art and position on the tech tree (Globalization).
I must respectfully disagree, Xyth.
I like this but it puts the Ironclad very close in strength to the Destroyer (22 vs. 24) and I'm not sure that's desirable, even with the Destroyer's more defined role.
Here's a potential compromise:
Frigate: 12 strength
SotL: 15 strength
Ironclad: 20 strength
Torpedo Boat: 18 strength, +50% coast attack
Cruiser: 30 strength
I'm perfectly fine with that.
Mahler, look at the rest of the tree- look at the gap between the Galleass and the Frigate, or the Dromon and the Galleass, or the Cruiser and the Missile Cruiser. Strength ratios of 4/3 between the new and old units are
routine. Ratios of 3/2 are common; even ratios of 2/1 are not unheard of (i.e. Crossbowmen upgrading directly to Riflemen).
Torpedo Boats are also very cheap to build and this is why I set them to be slightly weaker than the Cruiser (24 vs. 28). 1 on 1 the Cruiser is likely to come out ahead but a Cruiser up against a small group of them doesn't stand a chance. Especially given their first strike and withdrawal chance makes it very hard for a Cruiser to actually sink them. From what I read about the history of Torpedo Boats, they were indeed employed in numbers like this.
Yes, although so were destroyers, aircraft, and for that matter infantrymen. The game is often deliberately vague about exactly how many planes, ships, or men go into a single in-game "unit." While we can reasonably assume that one Nuke is a (MIRV-capable) nuclear missile, and that one Battleship unit is indeed probably one or at most two Battleships, I don't think we can assume that one Destroyer unit (which is surprisingly close to being able to kill a battleship, in vanilla) is just one destroyer.
That said, yes torpedo boats were used in packs, and indeed that was basically the only way to use them effectively. They weren't
really a very effective weapon, to be honest, being at a gross disadvantage in combat except under ideal conditions. Their influence was more felt in the way the implicit threat they posed had a huge effect on naval design and tactics. People started designing big-gun warships to give them longer gun ranges, mounting secondary batteries of light quick-firing guns to defend agains the torpedo boat, and abandoning the Age of Sail tactic of the close blockade (which became very unsafe if there were torpedo boats in the harbor).
I still support keeping Torpedo Boats in the game in some capacity because it gives you more flexibility and enriches the naval tech tree, though.
I currently have the Galleass at +25% coastal defense for the next version. I'm still evaluating it.
That sounds good- strong enough that they at least come within shouting distance of the strength of the frigate, but not strong enough to win reliably, or to make it totally impossible to defeat a Galleass before the frigate shows up.
Historically the Galleass was transitional between the oared war galleys of pre-gunpowder times and the 'broadside gunfire' design scheme of the Age of Sail. Large galley fleets sometimes used the physically larger and better-armed galleasses as strongpoints anchoring the galley formation. Attacking them with galleys could be extremely dangerous, because the galley was designed to row straight for the side of an enemy vessel and smash it up with a ram... whereas that was where all the big guns were on a galleass, so you were literally right in their line of fire. This was a major factor at Lepanto, for example.