S.33 class high-endurance boat

The S.33 class high-endurance boat was a class of Syrvanian submarine. It was Syrvania's only known indigenous design, and was built entirely in secret in Syrvanian shipyards.

While surviving documents make mention of these submarines, suggesting the construction and commissioning of at least ten boats, no technical specifications are known, no photographs survive, and of the scuttled hulls, none were intact enough to gather sufficient technical data beyond their estimated basic dimensions, and apparent influences from the earlier S.24 class, as well as the Kathyrion class cruiser submarines of the Bressian navy. The number of completed hulls and combat performance are also unknown.

Estimated Specifications
The S.33 class submarines were believed to have been between 90 to 93 meters in length, with a beam between 8.2 and 8.5 meters. They most likely had an armament consisting of eight 550mm torpedo tubes, six forward and two aft, with external fixtures suggesting anti-surface and heavy anti-air armament forward (most likely a 78mm cannon), and medium anti-air armament (most likely a dual 40mm or quadruple 20mm turret) or multiple light anti-aircraft guns in the rear of the conning tower.