if the breakwater is fonnded in sea water | and to 



3 



r'0,7 K' 3.^ H 



(1»09 cos a - sin g)^ (S - l)^ 



(it2) 



if it is fournded in fresh water. The wave height H to be used is that height 

 Xifhich wo-uld exist in the absence of the brealwater. This x-fave height at the 

 breaJ-tirater's position may be related to a deep water wave height H bj 



H = H (H/H<) X K (ll3) 



r 



where H = the deep water vjave height. 



K° = the refraction coefficient at the breakirater's 

 depth (determined from refraction diagrams) 

 (H/H') = the shoaling coefficient, values of which are, 



tabulated Appendix D (HJ| is the wave height which 

 would exist in deep water if the wave at depth d is 

 Ujiaffected by refraction.) 

 22lio The Equations for T/eights of Sub-Surface Stones . - The only method 

 presently available for the determination of sub-surface stone weights is 

 that suggested by Iribarren and Hogales, In this method, a hypothetical 

 wave height H' is determined, whose maximum orbital velocity is tlie same as 

 that which exists at the depth d. Tbd.s value is 



ttH - 



L smh -^p— 

 o L 



where H , the height of a wave steepened by the breaki-jater, is determined 

 by extending equation (ii3) to points over the brealcwater slope. This 

 hypothetical wave height is then substituted in equation (Ul) or (l'.2) with 

 K' = 0,0l5 or 0.019 (as determined from Iribarren), 



225. Charts and Tables (Description) . - The follol^^ing charts and tables 

 have been included to facilitate the solution of the basic equation 



G K' S (H or H«)^ 



M = E ^ (1,5 ) 



(1.09 cos a - sin a)-^ (3.^ - 3 )-^ 



where C = 88.3 and 3„ = 1.03 for sea water (li6) 



and C = 72. U and S^ = 1.00 for fresh water (li?) 



T.h 



