A Fortress is a typically heavily armoured, floating platform with insane firepower. They have the power to deal out heavy-damage, while taking little back in return. Ramming them is useless, since stability and weight will come naturally on typical forts.
Typical fortresses almost always have 46cm Guns, and a lot of them. They also have AA (Anti-Aircraft) weaponry to deal with planes. They will also have secondary armament to have a more constant firepower.
In in addition to heavy cannons, they also make use of aircraft, to add even more firepower. If one uses a lot of guns above deck, or uses a smaller ship, they might add runways below the deck, just note that if the ship is crippled, the runways will sink below sea level, making it impossible for aircraft to land, or land effectively.
Composition and Appearance
Depending on the desired size, one can use differing blocks. These are the recommended or likely used blocks:
600 millimetre armour (2x2x2, 1x1x1, etc)
400 millimetre armour (6x2x2, 3x2x1)
Most fortresses will usually be square platforms, and will usually be caked with guns and heavy armament. More skilled builders may take on a circular shape. Please note that is important to protect all sides equally as you could be flanked.
Most fortresses have little to no mobility, since they rely on their strength/armour/toughness for survival.
However, some fortresses may be equipped with minor mobility for positioning or to chase run away ships (like carriers).
Most fortresses will almost always have a toughness above 15,000. Extreme grinders or hackers can reach as high as 30,000 plus, making it very difficult to sink.
Expect a high stability; this is due to the large and usually equally spread out surface area. Furthermore, most fortress will be very heavy, so ramming one is a stupid idea.
Fortresses are kings of the seas; the only way to counter is with a powerful submarine or a super-warship, but even then, it is still difficult.
The best way to counter would be to have a fortress of equal or higher power. It is strongly recommended that you use powerful guns, as small armament, even missiles, will do little to no damage to the fortress whatsoever.
The future is questionable for the fortress. Ships are being able to move faster, which can be a nuisance to fortresses. In addition, the battleship is slowly being phased out, with the addition of compact but powerful guns, like the mk45, some fortresses will be superior, even if they are the tiny ones. The larger ones might not survive such a fight, being huge and poorly mobile, but those who are outfitted, will still stand. Some ships can be fitted to work in this new age, but those that can't compete, will be scrapped.