Well, seeing how much the audience appears to like these things, here's a third Nationstates ship. Like the carrier, this one is not inspired in any real project and is instead 100% original.
It's the Rezonans-class guided missile submarine, codenamed "Project 961". It's meant as a replacement for an aging fleet of Oscar-class submarines that, in the 21st century teather of warfare, are already starting to suffer from both hull wear and noise levels which are quite obstructing to its main task of sneaking up to enemy aircraft carriers and destroying them from long-range with missile fire. Rezonans does pretty much the same, albeit with a renewed set of systems to increase its lethality against current and future aircraft carrier groups, starting by replacing the Oscar's main weapon, the P-700 Granit missiles, with 24 tubes for Kh-90 Gela ramjet hypersonic anti-ship missiles, while keeping 10 torpedo tubes with 30 torpedoes for self-defense against submarines and quick ships that hunt it down. An odd addition for a submarine, it's equipped with 4 7-short Klinok launchers to destroy anti-submarine aircraft, helicopters, missiles and bombs when surfaced, though there are plans to replace them with heatseekers that can be fired while submerged.
More importantly, though, the MGK-540 sonar system found on the Oscar-class has been replaced with the MGK-590, a sonar system with an enormous spherical array that's so huge that it requires the torpedo tubes to be slanted, making the torpedoes come slightly to the sides of the ship. On top of the main frontal array, there's also very low frequency and low frequency arrays on the sides, an active sonar on the sail and mine detection sonars above and below the main array. This allows the submarine to make full use of the very long range of its missiles and be able to direct its missiles from more than 500km away from its target if the conditions are right, giving it enough time to escape any possible anti-submarine retaliation that may ensue. It can expel its whole ammunition load in less than a minute, and the missiles themselves can further network with each other mid-flight so as to narrow down the location of the enemy ships using active radar.
Also it posesses a much smoother shape than Oscar, designed to reduce low-frequency noise caused by turbulence and a ducted propeller to reduce the mid-frequency noise of the propeller, as well as to prevent cavitation from its tips when going at a high speed. It's been made with as few protruding components as possible, which makes its handling in ports a titch hard as the thick ropes need to be passed through dents in the outer hull. It's also quite expensive for its size, at 2.56 billion USD per ship.
Drawn in shipbucket's scale