CONTENTS Page xiii 



Page 



Fig. 157. Reduction of topography by radial-line method 696 



158. Protracting three-point fixes with three-arm protractor 698 



159. Sextant fix plotted by intersection of loci. No common center object 702 



1 60. Plotting R. A. R. positions with Odessey protractor 703 



161. Dead reckoning adjusted to astronomic sights 708 



162. Reduced sounding equivalents for smooth sheet and chart 717 



163. Sizes and placement of sounding numerals and other data on smooth sheet 723 



164. Right-hand page of Sounding Record with corrections properly made 726 



165. Subplan of small cove on smooth sheet 727 



166. Subplan of pier with soundings alongside 728 



167. Depth curves in vicinity of shoals 731 



168. Relationship of rocks to tidal datum planes 735 



169. Special symbols for use on hydrographic sheets facing 743 



170. Orientation of names on survey sheets 746 



171. Section of completed smooth sheet following 748 



172. Record of handlead and wire soundings — sextantfixes 754 



173. Record of echo soundings — sextant fixes 755 



174. Record of echo soundings — R.A.R. control 756 



175. Facsimile of Personnel stamp 759 



176. Facsimile of Sounding Apparatus stamp 760 



177. Facsimile of Stamp No. 34 760 



178. Facsimile of stamp for comparison of sounding apparatus 761 



179. I'acsimile of stamp for log and revolution-counter readings 765 



180. Facsimile of Line Begins stamp 766 



181. Facsimile of stamp for verification of sextants and clock 767 



182. Facsimile of Statistics stamp 768 



183. Facsimile of Processing stamp 774 



184. Record of Radio Acoustic Ranging data 776 



185. Symbols for progress sketches 794 



186. To locate a large closure error in a buoy traverse 866 



187. Nomograph for derivation of velocity of sound in sea water (0° to 15° C) 877 



188. Nomograph for derivation of velocity of sound in sea water (15° to 30° C) 878 



189. Symbols and abbreviations for nautical charts folloiuing 888 



190. Section of finished nautical chart following 888 



TABLES 



Table 1 . Scale equivalents for laying out sheets 25 



2. Personnel of survey units -i 28 



3. Requirements for triangulation and traverse 75' 



4. Corrections to sextometer distances 98 



5. Statistics of typical hydrographic survey projects using buoy control 147 



6. Spacing of sounding lines 201 



7. Sediments classified by size 304 



8. Survey ships of the United States Coast and Geodetic Survey in 1942 312' 



9. Auxiliary vessels of the United States Coast and Geodetic Survey in 1942 313^ 



1 0. Probable error of rangefinder distances 382: 



11. Map measure conversion table (measurements in centimeters to statute or nautical 



miles) 431 



12. Acoustic transmitting and receiving units. _J 452 



13. Tachometer reed values for 808 Fathometer 469 



1 4. Parts and circuits of Dorsey Fathometer No. 3 488 



1 5. Depth ranges of Dorsey Fathometer No. 3 490 



16. Functional operation of Dorsey Fathometer No. 3 490 



17. Faulty operation or failure of Dorsey Fathometer No. 3 491 



18. Circuit voltages of Dorsey Fathometer No. 3 492 



