My Shipyard

- Castrum Class Island Fortress -

Belongs to the OP-verse

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With the plan for revenge against the gods and those who imprisoned them approached, the Shadow Empire started making huge industrial efforts to boost their military production and be ready for the savage conflict. The biggest obstacle considered by the Imperial Shadow Navy was the control of the vital chokepoint: The portal that would block the only passage to the Third Dimension, if in enemy hands. Although the previous large capital ships were deemed enough for some of the officers, for others a far stronger and larger ships were needed to make absolutely sure that the chokepoint would be held, and because of those, the largest class ever built by the Shadow Empire started being researched and constructed, the Castrum class of Island Fortresses.

Because of the incredible amount of resources that needed to be spent on this project, Castrum, the first of the class, was only deployed halfway through the war, after the Shadow Empire started making its comeback and, despite its defensive purpose, it was used in the final battle of the First Shadow-Celestial, refueling and repairing ships that were being used against the Celestial Empire defensive installations and fleets. Later on, he would be assigned to protect the portal to Dark's Dimension. The other two island fortresses of the class, Ars Imperatoria, and Invictus, were built after the war during the times that Shadow Empire was corrupted and they only saw action during the Second Shadow-Celestial War, assigned as a base for attacks against the other nations and protector of the portal that leads to Light's Dimension, respectively. All of the three were sunken during the second mentioned war.

The Island Fortress class, one of a kind type of warship, was shaped in a large giant square when looked from above, with many different floors for different purposes and to accommodate the supplies, crew, and the number of armaments and aircraft that Castrum class carry. A total of seven floors were present in the warship, designated as:

- The Underwater Floors (1st and 2nd UF, for short), also called the essential floors for having the storage of ammunition, fuel, and repair materials, as well as the engines that powered the many propellers of the Island Fortress, put in equal amounts on each side of the square and allowing the Castrum class to hit up to 10 knots only, but travel to any direction without having to take time to turn. Those floors also had the best sonar equipment of the Shadow Empire's arsenal, to help the island fortress deal with submarines as earliest as possible. Given the strategic placement of the essentials below the waterline, it makes it harder for enemy ships to hit the Island Fortresses if the many walls on the floors weren't enough to stop a shell or a torpedo.

- The 1st Surface Floor (1st SF), also called the docking floor, was the one where allied warships would dock with the Island Fortress for repairs and resupply. In total, the Castrum class could have up to 24 Divinus battleships that had been cloned, and the space for docking those ships had to take a little bit of the floor directly below and complete the space of the floor above. There was a plan to later install 24 of the recently discovered 13 cm guns of the Celestial Empire on this floor, which could provide protection to the docked ships but had their range significantly decreased to protect only the docked ships, not the ones sailing the near Castrum, but they were only installed after the First Shadow-Celestial War ended.

- The 2nd Surface Floor (2nd SF), also called the living floor, is one of the two floors that doesn't look like a square if looked at from above due to the space stolen by the docks on the 1st SF, which is the other floor that isn't a square. This floor was called this way for having the quarters of the Castrum's crew, as well as extra ones for the crew of the docked ships, without even counting the canteen, training ranges, and leisure places to entertain the crew on their time there. Next to the docking areas, this floor also had cranes to help with the repairs and cargo transfer, and for combat, this floor was equipped with surface radars to detect enemy ships incoming, and around 28 guns of 10.5 cm against lightly armored vessels and submarines due to ASW shells, and 32 machine guns for even lighter and faster targets like landing craft.