Abstract: A leak detecting device for a fluid filled vessel including a housing, a solid shaft, an anchoring attachment, and a resilient member. The housing has a continuous perimeter edge sized to extend around an underwater surface, forms a hollow interior, and includes a first aperture formed through a wall of the housing and a second aperture formed through the wall of the housing. The solid shaft extends through the first aperture of the housing and has a first end on an interior side of the housing and a second end on an exterior side of the housing. The anchoring attachment is secured to the first end of the solid shaft. The resilient member is secured to the perimeter edge of the housing.