Abstract: Apparatus (10) for sealing a rupture (11) in a wall (12) having fluid on one side, the rupture forming petals (13) extending away from the wall. The apparatus is formed by a resilient backing plate (18) for fitting around the rupture, fastening magnets (14) attached to backing plate (18) for attaching the backing plate (18) to the wall (12), a resilient seal, such as an O-ring (19), adjacent the backing plate (18) having an aperture for positioning over the rupture, and a fluid-tight enclosure (20) extending over the aperture in the seal to cover the rupture. The resilient seal (19) is compressed against the wall (12) to substantially seal against any flow of fluid leaking through the rupture when the backing plate (18) is attached to the wall (12).