It is a heavy strong member (large casting, forging or weldment) attached to the aft end of the ship keel. The structure of the stern frame depends on the stern profile and rudder type. There should be adequate clearance between propeller and stern frame to reduce the vibration.
> Stern frame carries the boss and supports the after end of the sterntube.
> Rudder is usually supported by a vertical post which forms part of the stern frame.
> Stern frame is constructed such a way that it suit the form of the hull and stremlined to reduce the turbulence of water.
