[Vespers War]

Another existing fort that could be of use in a campaign involved in the Gulf of Mexico (whether that follow on from Spanish Main, Urban Guerilla, or Red Star) is Fort Jefferson. The third-largest fort in the United States, it takes up 70% of the land area of Garden Key, Dry Tortugas, about 70 miles west of Key West. The fort's parade ground is 13 acres, surrounded by six brick-and-concrete walls that are eight feet thick and forty-five feet high. It's large enough to house 2,000 people and 450 cannon, and contains around 16 million bricks.

The fort was built for its strategic location and harbor. The inner harbor was deep enough for line-of-battle ships, but its entrance was only 120 yards across. The island already had a lighthouse, which the fort was built around (it was later torn down and another lighthouse built). It provided for a secure harbor from which to patrol the Gulf of Mexico and the entrance to the Straits of Florida.

It's much more open now than it was originally; all of the gun embrasures were fitted with Totten gunports. The eight inch thick iron shutters were balanced so that the gasses leaving a cannon's barrel before the shot would push them open, with the shutter rebounding closed after the shot passed through. Over a century and a half, they were damaged by water and began cracking the fort's facade by swelling, so they've been removed. A would-be pirate king would want to find ways to fill some of that open area with protective cover.

The one weakness of the location is a lack of fresh water. The design attempted to solve this by placing columns of sand within the walls of the fort, leading to cisterns below, so that rainwater falling on the fort would drain through the sand as a filtration medium. Unfortunately, the sand that was used contains mineral salts, so the water is undrinkable, though it can be used for washing or cooking if the cracked cisterns (from settling) can be patched. When the fort saw its heaviest use during the Civil War, steam condensers were used to produce water, and a post-Twilight War occupier would need some sort of method of producing drinkable water, possibly salvaged from ships.