PURPOSE: To provide a steel reinforcement-cement structure equipped with anti-shock strength and hardness enough to be used for a hull.

CONSTITUTION: A shell body is made by assembling steel wires into a predetermined shape. On its outer surface, mortar whose aggregate and cement are added with a mixing agent of an acrylic polymer or a latex polymer, is coated. After hardening, the surface is solidified by means of epoxy putty and paint, and hardness is possessed. It is desirable that what are selected from glass powder whose grain diameter is 30-40μm, pumiceous baloon and micro-baloon, are used for the aggregate.