Abstract: A foldable sink box consisting of a rigid plasticized hull and a buoyant platform having a large central aperture for engagement by the rigid hull in assembled condition. The hull defines a relatively deep well, for sitting engagement by a hunter. The platform defines two halves, interconnected by an intermediate lengthwisely-extending hinge member. Locking brackets releasably lockingly interconnect the platform to the top edge portion of the rigid hull, concurrently with releasably locking the platform halves in coplanar fashion.