PREFACE 



This 1960 edition (C&GS Public<ation 20-2) of the Hydrojrraphic Man- 

 ual is issued as a guide to efficient execution and processing of hydrographic 

 surveys. Present edition supersedes the 1942 edition (Special Publication 

 143) and Hydrographic Instnictions 1 through 13 of 10/8/54 to 3/19/58. 

 Although obsolete in many respects, particularly as regards rapid develop- 

 ments in control systems and eclio soiuiders, the 1942 edition is still an excellent 

 reference work and existing copies should be preserved. 



The subject matter in this manual is identified by a numbering system 

 in which the fii-st number identifies the chapter and the second numbei' 

 identifies the section in the chapter. Cross references are entered by numbere 

 in the same manner; for example the notation (see 1-26) refei-s to Chapter 1, 

 Section 26. 



This edition of the Hydrographic Manual has been compiled with the 

 assistance and advice of many officers and personnel in the office and the field. 

 Special credit is due Mr. G. F. Jordan who wrote the firet draft of Chapter 6. 

 The Smooth Sheet; to Mr. R. H. Carstens wlio reviewed a large part of the 

 manual and contributed nuich valuable information; to pei-sonnel from the 

 Electronics Laboratory for their contributions to Chapter 3; to the officei-s 

 who reviewed the manuscript; and to Mr. C. E. Cook for his assistance in 

 preparing the index. 



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