34 NAUTICAL CHAET MANUAL 



Disposition of bridge clearance data: 



1. Bridge card completed in accordance with listings thereon by Nautical Data Branch 

 personnel. 



2. Data transferred to Aid Proofs of affected charts. 



3. Bridge card given to Chief, Aids to Navigation Section for publication in Notice 

 to Mariners. 



(a) If no Notice is required and correction is to be made only at next printing, a 

 copy of the bridge card is forwarded to the Coast Pilot Branch and so noted 

 on the card. 



4. Clearance data transferred from Aid Proof to revision drawing by cartographer. 



(a) Location of structure added to revision drawing by cartographer from origi- 

 nal source material. 



The three charting phases of bridge structures are as foUows: 

 1. Commencement 



(a) Add dashed-line symbol. 



(b) Designation "Bridge under construction." 



(c) Magenta screening on important waterways supplemented by caution note 

 calling attention to probable hazards to navigation in area (see Figure 12). 



2. Completion prior to Corps of Engineer inspection. 

 (a) Add authorized permit clearances. 

 Example: fixed bridge 



'^ HOR CL 100 FT. 



(b) Delete magenta screening. 



3. Corps of Engineer inspection "as built" clearances. 



(a) Revise clearances as necessary. 



(b) Delete AUTHORIZED. 



All fractions of a foot shall be disregarded in determining the final charted clearance. 



For symbols representing various types of bridges, see Symbol Sheet (Chart No. 1) items 

 H-14 through H-18b. 



The terms Left and Right, when referring to bridge spans and river banks, mean Left 

 and Right proceeding downwardly toward mouth of stream, and in the Intracoastal Waterway, 

 proceeding south on the Atlantic Coast and west on the Gulf Coast. 



