CONTENTS IX 



ILLUSTRATIONS (Continued) 



Figure Page 



65. Record of echo soundings — Shoran control 168 



66. Sample record showing application of rules for corrections 



to soundings — 169 



67. Facsimile -of stamp No. 39 .— 171 



68. Facsimile of stamp No. 36 172 



69. Hydrographic statistics stamp — _ 172 



70. Stamp for record of processing 172 



71. Curve of velocity corrections to echo soundings 184 



72. Velocity correction graph, Form 117C 186 



73. Fathograms showing side echoes, kelp, and grass 190 



74. Problems in fathogram interpretation 191 



75. Probable position of ship from steller observations 197 



76. Temporary sheet extension or dog-ear 201 



77. Subplan of small cove on smooth sheet 201 



78. Control station plotted by dms. and dps. on distorted sheet . 206 



79. Symbols for use on hydrographic sheets (facing) 207 



80. Shoreline delineations on the smooth sheet 208 



81. Cartographic treatment of alongshore rocks 211 



82.. Section of completed smooth sheet (follo7ving) 217 



83. Section of smooth sheet showing treatment of congested 



hydrography (following) 217 



84. 3- and 4-digit soundings plotted at an angle. 221 



85. Special problems in drawing depth curves 224 



86. Change of datum of survey sheet, ._ ._ „ 236 



87. Nomograph for derivation of velocity of sound in sea water 



(15° to 30° C) 261 



88. Nomograph for derivation of velocity of sound in sea water 



(0° to 15° C) 262 



89. Standard widths of lines 263 



