An anti-puncture, water-leak-inhibiting, self-sealing, coating structure for application selectively to inside and/or outside portions of a boat hull. The coating structure, in operative condition with respect to such a hull portion, includes a body of continuous-phase, non-water-reactive, high-elastomeric-material, and, embedded within that body, in an initially shrouded and non-exposed condition guarded nominally against any contact with external water, a distribution of water-reactive, water-imbiber beads.