How to moderate ship the damages caused by the underwater explosion (UNDEX) is of great interest to the modern ship designers. A new type of rubber sandwich with periodic honeycomb core was developed to mitigate the ship shock due to UNDEX. A ship with or without the rubber coat was tested under “near combat conditions” by igniting a 8 kg charge of TNT underwater at varying standoff distances from the ship. The effects of the shocks to ship systems were observed and the responses of the ship were monitored and recorded for each shot. The pressures in the water around the ship were also recorded to explore the fluid-structure interaction and UNDEX shock wave reflection with different targets. Acceleration and strain records indicate that the rubber coat is capable of moderating the high-frequency response excited by shock wave efficiently. Pressure records show that the core crushing and water cavitation promote superior energy absorption that yields an increased resistance to UNDEX.