A new and revolutionary form of naval warfare was introduced in the era of the Ultra-Battleships for shore bombardment and also for naval combat, trying to complement the big calibre guns, howitzers and mortars.
The North-Pole Conglomerate engineers soon realized that ultra-big caliber artillery pieces (1,000 to 2,000 mm) had very low rate of fire as to maintain a moving enemy ship as a target, making a direct impact by chance. This is a non-practical proposition given the cost of each artillery shoot and of the whole ship in campaign.
The idea behind a the cruise missile is simple, but the mechanical behind is complex. Cruise missiles are V.T.O.L. aerial machines that fly guided to his target by a programming path, and stabilized by a gyroscope. To hit a moving target, is needed instead some sort of terminal guidance, by wire or by radio signals. The fly can be monitored from a high post in the ship or even from a manned aircraft that fly near the target.
South-Pole floating islands engineers have developped the Ecuatorial Fortresses long time ago, but recently have deployed new weapons inside the main concrete towers. They mastered the salvo-shooting of a kind of multi-tube mortars capable of fire, in rapid sucession, six 1,200mm calibre, 5,000 Kg armor-piercing projectiles against the North-Pole Conglomerate Ultra-Battleships.
Even more recently, it is said that they are employing a new multiple device of rocket nature, so the weapon dispenses with the recoil and also can be reloaded quickly. It is a multiple rocket launcher with five or six tubes that launch spin-stabilized projectiles of 2,000mm diameter and 12,000 Kg in launching weight to 15 Km maximum range.
In this picture, a launching platform is shown with his armored dome open and a silo also opened. The V.T.O.L. missile is deployed and is ready to spin his propellers to fly automatically toward his intended target.
NOTE: in this polarized oceanic world that I imagine, only vertical take-off and landing aircraft exist. These machines are propelled by rotating wings. No other form of aerial flying is know or is allowed by strictly-observed War Laws, except artillery projectiles.