steampunk submarine 3d model

Futuristic spacecraft, total length 800 meters, height 300 meters, width 300 meters, smooth armored hull similar to a heavy sci-fi cruiser. Add a solid structural ring attached directly to the hull at the exact midpoint of the ship (400 meters from the nose). The ring wraps completely around the ship, coaxial with the main axis. Ring dimensions: 80 meters long along the ship’s axis, 30 meters radial thickness. Inner diameter of the ring: 304 meters, outer diameter: 364 meters. The ring is fully integrated into the hull with reinforced structural ribs and smooth beveled transitions, no gap between ring and ship. Dark metallic materials, realistic industrial detailing, vents, panels, and structural seams. Hard sci-fi aesthetic, realistic scale, high detail, cinematic lighting, neutral background.