254 



HYDROGRAPHIC MANUAL 



ferent divisions should not be combined in 

 one transmitting letter. 



7-25 Data to be forwarded. — For con- 

 venient reference there is given herewith a 

 summary of the data to be forwarded to the 

 Washington Office in connection with dif- 

 ferent types of hydrographic surveys. This 

 list should be consulted before the records 

 and reports are prepared for shipment. 



A. For every hydrographic survey. 

 Smooth sheet : 



Copy of hydrographic title sheet (Form 

 537). 



Blue line tracings of shoreline manu- 

 scripts. 

 Boat sheet: 



Overlays (when applicable) . 

 Sounding records. 

 Fathograms. 

 Descriptive Report: 



Hydrographic title sheet. 



Processing Office addendum (when 

 applicable). 



Overlay tracings of congested areas. 



List of control stations. 



Abstract of corrections to electronic 

 distance measurements (when 

 applicable). 



Tide note. 



Abstract of echo sounding corrections. 



Geographic name list. 



Approval sheet. 

 Photogrammetric manuscripts. 

 Descriptions of topographic stations (Form 



524). 

 Recovery notes for topographic stations 



(Form 524). 



B. Season or Area Reports. 

 Echo sounding correction reports. 

 Calibration of electronic control systems 



(when used). 

 Temperature and salinity observations. 

 Landmarks for charts (Form 567). 

 Positions of fixed aids to navigation (Form 



567). 

 Coast Pilot notes. 

 Geographic name report. 

 Season's progress sketch. 

 Triangulation progress sketch. 

 Triangulation station descriptions (Form 



525). 

 Triangulation station recovery notes 



(Form 526). 

 Current observations. 

 Magnetic observations. 

 Bathythermograph slides and log sheets. 

 Tide station reports and leveling records. 

 Marigrams. 



7-26 Report on corrections to echo sound- 

 ings. — A report on corrections to echo sound- 

 ings shall be submitted at the conclusion of 

 a field season or hydrographic survey proj- 

 ect. The method used to determine the 

 corrections shall be stated but need not be 

 described in detail except when an unusual 

 method is employed. The mean regional tem- 

 perature and salinity curves for each area or 

 period of time and the computations of ve- 

 locity corrections shall be included with this 

 report. The record of observed temperatures 

 and salinities should be bound and forwarded 

 separately. 



The abstracts of bar checks, vertical cast 

 comparisons, and phase comparisons should 

 be included with the report. Tables of cor- 

 rections should identify the soundings to 

 which they apply and a copy of the applicable 

 tables shall be included in the descriptive 

 report to accompany each smooth sheet. 



The report should include all basic data 

 adequately referenced and tabulated, includ- 

 ing graphs, so that calibrations can be 

 readily verified. When the report covers 

 several project surveys, or when various ves- 

 sels and echo sounders were used on the sur- 

 vey, a chronological tabulation should be in- 

 cluded which references ships, launches, and 

 echo sounders common to the surveys during 

 the operating season. This will facilitate 

 tracing basic information involved in correc- 

 tion factors. 



When a velocimeter is used in the deter- 

 mination of velocity corrections, the instru- 

 ment should be identified by number and 

 the date of the most recent calibration should 

 be stated. 



When an EDO-255 echo sounder is op- 

 erated at any frequency other than the stand- 

 ard 60 cycles, conforming to a calibrated 

 velocity of 800 fathoms (4,800 feet) per 



