The diffusion of air through the neoprone in the neoprene bellows of the 3 shore-wave recorders installed offshore at Orote Point, Ylig River, and Tarague Beach, necessitated that butyl rubber should be used in stead of neoprene in the Mk IX Mod 4 pressure head. Another change was the substitution of 20 cu in. of liquid silicone oil with a viscosity of 10 centistokes for air in the lower bellows. The filter restriction was enlarged. The damage to the wave recorders at Ylig River and Targue Beach caused by Typhoon Hester was such that completely new installations will be required. A more reliable method of anchoring the tripod was recommended in which the base would be anchored to large expansion bolts placed in holes drilled into the coral formations at least 2 ft deep.