3211 HYDROGKAPHIC MANUAL PaGE 204 



3211. Use of Boat Sheet in Smooth Plotting 



After the completion of the field survey a boat sheet has a use which should be 

 kept' in mind by the hydrographer during the progress of the work. It serves as a 

 guide and reference record during the plotting of the smooth sheet and its data should 

 therefore be free of ambiguity. When plotting the smooth sheet, weight is given to the 

 fact that the hydrographer was present at the time the survey was being made, knew 

 the vessel's position and, regardless of the recorded data in the Sounding Record, 

 plotted the positions on the boat sheet and connected them in accordance with the 

 known facts, even though lack of time may have prevented extreme accuracy. (See 

 767.) 



3212. Use of Boat Sheet at the Washington Office 



The boat sheet is referred to constantly during verification of the smooth sheet 

 at the Washington Office. If often contains supplemental details and notes which aid 

 in interpreting the Sounding Records, including some which should be transferred to 

 the smooth sheet. Occasionally the boat sheet is the sole source of or authority for 

 the positions of rocks, limits of breakers, areas of kelp, etc. Such information should, 

 however, be used with discretion, especially if it is not inked on the boat sheet. It is 

 incumbent on the verifier to see that all data of permanent value are already on or are 

 transferred to the smooth sheet. 



The boat sheet shall be available to the reviewer and for any other purpose in 

 connection with the survey, until after the review has received final approval by the 

 administrative officers of the Bureau. 



3213. Boat-Sheet Numbers 



A field number shall be assigned to each boat sheet in accordance with 1541. The 

 survey and all the records pertaining to it shall be identified by this number in all 

 correspondence, records, and reports until the registry number is assigned (see 1542), 

 after which the latter shall be used in lieu of the field number. 



Where the limits of a boat sheet are not identical with the corresponding smooth 

 sheet, the smooth-sheet number is the controlling factor in numbering the boat sheet. 

 If several boat sheets are used for a survey, which is all included on one smooth sheet, 

 the several boat sheets shall bear the same survey number followed by identifying num- 

 bers in parentheses, as H-5281 (1), H-5281 (2), etc. 



If, for any reason, the field survey for which one boat sheet was used has to be 

 plotted on two smooth sheets, the numbers of both smooth sheets shall be shown on the 

 boat sheet and on the Sounding Records involved. 



Before a boat sheet is transmitted to the Washington Office, both its registry num- 

 ber and its field number shall be shown in one or more places on its reverse side. 



322. Construction of Boat Sheet 



A boat sheet is ordinarily constructed in the same manner as the smooth sheet 

 (see 73 to 75) and with limits in approximate agreement with the latter. A layout of 

 the projection with distances noted thereon (see 7324) may be used in constructing the 

 boat sheet and saved for use again when the smooth sheet is made, if the projections are 

 to be identical. 



3221. Boat-Sheet Paper 



A good quality of cloth-backed paper obtained from the Washington Office should 

 be used for boat sheets. Where the sheet is to be used in bright sunshine, a buff- 



