The data presented previously have been corrected against the apparent values of incident and reflected wave heights. The transmission coefficient of a vertical wall breakwater with the rise R of the crest above the still water level has been expressed in the empirical formula of
　KT=HT/HI=0.5(1-sin(π/2α)(R/HI+β))
with revised values of the parameters α and β at 2.2 and 0.4, respectively. The re-analysis of transmission and reflection coefficients has shown that the relative loss of wave energy by a vertical wall breakwater is about 30 to 35 per cent at the maximum, which occurs when the crest of breakwater is slightly submerged.
　For the wave transmisson over a composite breakwater, the value of α has been determined at 2.2 and that of β at 0.1 to 0.35 depending upon the mound height. With the consideration of additional energy transmisson through the rubble mound, a formula is suggested for the transmission coefficient of a composite breakwater.