My take on the Haunebu II. One of the Nazi's "miracle weapons" supposedly. I know the underside orbs had some sort of turrets jutting out of them according to the plans. But i'm deviating from it. In my mind, they're part of the Tachyonator gravity vortex engine system used by the vessel. I reckon it's impractical for a vessel that is supposedly capable of insane maneuvers and speeds to have flimsy things attached to the exterior. Also the fact that such a vessel would use conventional projectile based weaponry is somewhat impractical. I'd imagine it utilized a form of scalar wave weaponry instead that could instantaneously strike targets at any angle, with great accuracy, without having to turn the vessel towards the target.
The original plan said it's about 26 meters in diameter. But I decided to make it a bit bigger. Also, the black orbs on the upper side are not windows as the plans suggest. They're sensor arrays instead.