with a smooth curve drawn to give the position of 

 crest 14. (Note that charts 5402 and 5403 have 

 been reduced by photostat for inclusion in this 

 report.) 



Starting with wave crest 14 on chart 5403, 

 crests 15 to 23 are plotted by the method illus- 

 trated in steps 1 to 4, above. Because the bottom 

 slope in the area covered by this chart, in general, 

 is relatively uniform, crests can be plotted using 

 a larger interval between crests; thus, crests 15 

 to 23 were plotted using scale A of figure 5. 



On chart 5402 the, spacing between crests was 

 determined by means of scale B and the corre- 

 sponding values of n and t are: 



.71=0.0163 



f=0.0163 



214,000 



(14)^ 



(214,000) 

 14 



= 17.8 wave lengths 



= 249 seconds 



Similarly, on chart 5403 scale A was used, and 

 the values of n and t are: 



71=0.0326 Q4yP =8-3 wave lengths 



(=0.0326 i^MM^in seconds 

 14 



At a few localities where the bottom configu- 

 ration is irregular, intermediate crests on chart 

 5403 (fig. 7) have been added by the use of scale 

 B. These localities are between crests 16 and 17 

 near a side canyon of the Monterey Canyon and 

 shoreward from crests 21, 22, and 23. Even this 

 spacing is inadequate to describe the refraction 

 which probably occurs at such locations as Santa 

 Cruz Harbor, Monterey Harbor, and at the head 

 of the Monterey Canyon at Moss Landing. For 

 greater detail in these areas, charts with a larger 

 scale should be used. Photostat enlargements, 

 of the areas from chart No. 5403 could be made, 

 but for more accuracy, the original USC and GS 

 work sheets should be used. Thus, figure 8 shows 

 contours from Hydrographic Chart 5415, which 

 covers Monterey Harbor and vicinity with a scale 

 of 1:5000. Inspection of chart No. 5415 shows 

 that the bottom contours extend seaward only to 

 the 17-fathom contour, which is about the location 

 of crest 23 on chart 5403. Crest 23, consequently, 

 has been transferred to chart 5415 by the offset 

 method described above. Crests 24 to 33 have 

 been constructed by the use of scale A. The 

 crest interval on this diagram is as follows: 



71=0.0326 ^^/f^y =0-83 wave lengths 



(=0.0326 (5.000) ^^^^ seconds 

 14 



Further detail near the Monterey breakwater 

 and within the harbor could be obtained by en- 

 larging that area from chart 5415. 



Upon completion of a plot showing the wave 

 crests, the orthogonals are drawn on the diagrams. 

 The orthogonals are started at the shore, or at 

 some specified depth contour, and carried seaward 

 as perpendiculars to the wave crests until deep 

 water is reached. In shallow water they are 

 curved lines but become straight lines in deep 

 water. A small triangle and a short straight edge 

 are convenient in constructing the orthogonals. 

 The triangle is adjusted to be tangent to a wave 

 crest, such as at a point a (fig. 9) where the orthog- 

 onal is to be started (crest 1). The straight-edge 

 is held against the triangle and the triangle then 

 slid along the straight-edge to permit a perpen- 

 dicular to be drawn through point a and to point 

 b half way to crest 2. The process is repeated 

 for crest 2 with the perpendicular being drawn 

 shoreward to point b and then extended seaward 

 to a point c midway between crests 2 and 3. The 

 procedure is repeated until the wave crest in deep 

 water is reached. If desired, a smooth curve then 

 could be drawn through the points where the per- 

 pendiculars cross the crests. The irregularities 

 in the wave crests indicate how closely the ortho- 

 gonals should be located. In figure 7 orthogonals 

 have been drawn every two nautical miles starting 

 at the Monterey Municipal Pier. With the ex- 

 ception of the vicinity of Moss Landing and north- 

 ward this spacing appears suitable for most of 

 the coast between the orthogonals A-F (fig. 7). 

 As mentioned above, if the refraction coefficients 

 are desired for the Moss Landing shore line, a re- 

 fraction diagram should be prepared on a larger 

 scale map, and the orthogonals should then be 

 drawn at a smaller spacing. Additional orthog- 

 onals should be constructed northward from Moss 

 Landing to better define the refraction coefiicients 

 in this area. 



It is to be noted that the orthogonals shown on 

 chart 5403 (fig. 7) ended at crest 14 and then had 

 to be transferred to chart 5402 (fig. 6). In all 

 probability, not all the orthogonals can be car- 

 ried to deep water on the smaller scale chart. 

 Only a few of the orthogonals actually are re- 

 quired to give a measure of refraction between 



10 



