As for the "brig" being a transport... I suppose it could be. But the truth is -- ANY SHIP COULD TRANSPORT TROOPS.
For instance, HMS
Endeavor, the famous bark (barque) used by Captain James Cook to explore New Zealand and Australia, was first used as a collier (shuttling coal about). After its voyage, it was again relegated to a cargo ship to ferry goods to the Falklands, and then sold to a private owner. At that time, it was renamed
Lord Sandwich and was used as a troop transport in the American Revolution until it was ignominiously scuttled by the British in the harbor of Newport, Rhode Island.
One of the big problems here is that Paradox designers are trying to conflate "rigging" with "purpose." In other words, it is fair to assume that the largest three- or four-masted ships in the game are "heavy" combat ships, and that the smaller two- or three-masted ones would be "light ships," but for some reason, they are taking the cargo vessel sorts (like fluyts and East Indiamen) to mean "transports."
However, East Indiamen and fluyts were both often outfitted and armed during time of war. The British used East Indiamen as "fourth rates" (46-60 guns). Fluyts were commonly used in the Baltic sea for protecting trade.
The other problem with the current system is that a huge percentage of your fleet is useless at most times. Heavy ships and galleys are only useful during war (or for pirate suppression if they do pop up), and transports are only useful, well, when you need to transport troops. This is far from how they were historically used. Even during peacetime, you'd have your ships-of-the-line out patrolling sea zones. You'd have your "transports" doing what they normally do -- carrying cargo around the world.
So, in other words, what is happening is that Paradox is trying to make clear delineations in the purpose of ships for the sake of the game that, unfortunately, do not line up well with reality. In reality, many ships were used one way at first, then changed later in their lives, possibly over and over again as needed by their owners, whether that was a government's navy, or a private owner.
So.... In short, here's what I would propose:
- All ships should be able to be assigned to "protect trade."
- Transports should have the best rating for producing income when protecting trade -- BUT -- if they are protecting trade alone, without any other form of escort -- they should not prevent the spawning of pirates in the zone. They might be able to fight off the pirates, or then again, they might be sunk or even captured.
- Light ships should have the next-best rating for protecting trade income.
- Galleys should have the third-best rating for trade income, but their rating might be doubled, thus better than light ships, in inland seas.
- Heavy ships should have the worst rating for income.
If Paradox
really wanted to hit one out of the ballpark, just as they are doing blockade values based on how many ships you have blockading, you could do pirate suppression based on the total "anti-piracy" values of your patrol, vs. the "lucrativeness" of the route -- which would be attracting pirates. Again, transports would get you zero anti-piracy value. Light ships would get the best. But a fleet of galleons? They might do quite swell to keep pirates away from your trade routes too.
Given this set-up, every player would likely have their entire fleets out protecting trade -- generating income and keeping pirates at bay -- all the time. And there would have to be some heavy thought given to whether you just spam light ships, or whether you want a few heavies mixed in just in case.
In the early game, a lot of nations might make an "all transport" fleet except, say, for a light or two to keep them safe from pirates.
Yes, I know this would be a radical departure from the game as it currently stands, but it is what actually makes the most sense, and it is what history would see as most logical.
As opposed to parking 80 three-deckers in Portsmouth, just in case Frenchy got feisty... >.<