Abstract: A baffle (1) for reducing hydraulic ram pressure in a liquid in a tank (5,9) in which it is located resulting from impact of a projectile on an external surface (6,10) of the tank, includes at least two outer walls (2) spaced apart to define therebetween at least one cavity (3) and a compressible gas or gaseous mixture at reduced, atmospheric or enhanced pressure contained in the cavity (3). The baffle outer walls (2) are sufficiently strong to withstand the pressure of the gas or gaseous material contained in the cavity (3) are sufficiently strong to resist the hydrostatic pressure of liquid in a tank (5,9), when the baffle (1) is located in the liquid in the tank (5,9), and are spaced apart by an amount sufficient to provide the cavity with a volume sufficient to allow a shock wave or waves in the liquid resulting from compression of the liquid by impact of a projectile on the tank external surface (6) to be reduced by expansion of the compressed liquid into the cavity volume.