1. IN A HYDRAULIC DAMPING DEVICE FOR USE IN A MOUNT FOR A ROCKET LAUNCHER OR THE LIKE INCLUDING A ROTATABLE AZIMUTH DAMPER HOUSING, A VERTICAL PINTLE ABOUT WHICH THE HOUSING ROTATES, A NON-ROTATING VANE SECURED TO SAID PINTLE WITHIN SAID HOUSING, A RAPID TRAVERSE MEMBER HAVING AN OPENING THEREIN SECURED IN SAID HOUSING AND HAVING AN ORIFICE EXTENDING THERETHROUGH, VALVE MEANS ADJUSTING THE SIZE OF SAID ORIFICE; THE IMPROVEMENT COMPRISING A RELIEF VALVE GATE PIVOTALLY MOUNTED IN SAID OPENING OF SAID RAPID TRAVERSE MEMBER TO PERMIT LATERAL SWINGING MOVEMENT IN TWO DIRECTIONS, MEANS HOLDING SAID GATE IN A CLOSED POSITION PRIOR TO A SUDDEN RUSH OF FLUID, MEANS LIMITING THE SWINGING OUTWARD MOVEMENT OF SAID GATE, AND MEANS RETURNING SAID GATE TO THE CLOSED POSITION FROM EITHER OF THE TWO DIRECTIONS WHEN THE RUSH OF FLUID SUBSIDES.