Page 657 71 



CHAPTER 7. THE SMOOTH SHEET 



The smooth sheet is the name given to the hydrographic survey when reduced to 

 plot form. It is essentially a record of the soundings taken during the field survey, 

 but contains other data necessary for a proper interpretation of the survey, such as 

 depth curves, bottom characteristics, names of geogi'aphic features, and control 

 stations. The smooth sheet is plotted with the utmost care in the drafting room of the 

 ship or a field office either as the survey progresses or after it is completed. After 

 registry, verification, and review in the Washington Office (see 93), the smooth sheet 

 becomes the official permanent record of that particular survey. It is as complete for 

 the water area as it is practicable to make it, and subsequent reference to the original 

 Sounding Records is rarely necessary. 



71. THE SHEET 



711. Smooth-Sheet Paper 



It is obvious that surveys which cost thousands of dollars to execute should be 

 plotted in their final permanent form on the best practicable medium available. Ex- 

 perience has shown this to be first-quality white drawing paper mounted on muslin. 

 This paper is known as smooth-sheet paper, and is available in several makes and sizes. 

 Smooth sheets shall be prepared only on paper furnished by the Washington Office 

 for that purpose. 



7111. Whatman^ s Paper 



The standard paper for smooth sheets is Whatman's paper, available in only one 

 size, 31 by 53 inches. In this paper the muslin backing extends approximately 1 inch 

 beyond the paper on each edge, which feature tends to preserve the edges of the paper 

 during extensive use and also prevents cracking. Whatman's paper shall be used for 

 all smooth sheets where the size permits, and this requirement must be given full 

 consideration in planning the sheet layout for any given area (see 1361). 



7112. Other Papers 



Other mounted smooth-sheet paper is available in widths of 36 and 42 inches, in 

 continuous rolls of 10 yards each. This should be used when the layout of sheets 

 requires the use of larger sizes than the standard, as is frequently the case with offshore 

 surveys. The quality of the different makes varies, "Paragon" being considered the 

 fuiest drawing paper made. But this is foreign made and is difficult to get at the pres- 

 ent time. In 1942 the best available paper is Keuffel & Esser No. 13320 DM. 



465382—44- 



