to obtain 
5) 3 3} 
K! er S S,A H 
wie ie r (2) 
(A cose - sine )? (oa a)" 
in which the additional symbols are: 
t 
i 
unit weight of fresh water 
Sp = specific gravity of the fluid in which the breakwater rests 
WZ) 
K! 
effective coefficient of friction rock on rock, & 1.09 
a variable dimensionless empirically determined coefficient, 
values of which as determined by Hudson are plotted in Plate 4. 
the equivalent values for equation (1) are 
K' =0.015 for natural rubble 
K' = 0.019 for artificial blocks 
The Equations for the Weight of Above Surface Stones 
Equation (2) may be reduced to 
ta o 3 r 
W = 88.3 K! Yr H (3) 
(1.09 cose - sinee )? (Sp - 1.03) 
if the breakwater is founded in sea water; or may be reduced to 
c 
aia 1.7 el SB. Be 
W = 80.7 K! Yr H (1) 
(1.09 cose - sinee)? (Sii=a)iz 
if it is founded in fresh water. The wave height H to be used is that height 
which would exist in the absence of the breakwater, This wave height at the 
breakwater's position may be related to a decp water wave height H, by 
eo Tel (yA) os Tc (5) 
where H, = the deep water wave height 
a 
7] 
x 
$ 
i 
the refraction coefficient at the breekwaters depth 
(determined from refraction diagrams) 
(H/H'..) = the shoaling coefficient, values of which are tabulated in 
fo) 
ROMerencemo (HE is the wave height at depth d if ume eee eee 
by refraction) . 
a2 
