RULES AND PRACTICES 33 



BRroGE CLEARANCES (H-18a,-18b) 



Bridge clearances, both horizontal and vertical, shall be shown on all Small-craft, Intra- 

 coastal Waterway and large-scale Conventional Charts. On small-scale charts, clearances 

 shall be shown at fixed bridges spanning waterways that are expected to be navigated at the 

 scale of the particular chart. 



Bridge clearances and classifications shall not be shown on waterways which are not repre- 

 sented by depth cm-ves, soundings, or depth legend. The charting of such clearances, omitted 

 or removed from existing charts, shall be reconsidered when larger scale charts of the area are 

 published. 



The Corps of Engineers shall be the authority for showing bridge clearances on nautical 

 charts. 



However, for those bridges which the Engineers have not furnished or published clearances, 

 clearances from another reliable source may be charted pending receipt of data from the Corps 

 of Engineers. Bridge clearances from som-ces other than the Corps of Engineers shaU be 

 labeled "REPORTED." 



It shall be the responsibility of the Chief, Nautical Data Branch, to originate written re- 

 quests for the Bureau's field units at their first opportunity to verify "reported" clearances of 

 bridges considered important to the mariner. 



Verified clearances by our field imits shall be turned over to the Corps of Engineers. If 

 that organization accepts and publishes them, the "reported" label shall be removed from the 

 charts affected. If the Corps of Engineers does not accept C&GS values, the label "reported" 

 shall be retained. 



A card file (Form C&GS-961) of bridge clearances, compiled from available information, 

 is maintained by the Nautical Data Branch as foUows: 



1. Atlantic Coast and West Coast of Florida to longitude 84°00'. In this file, the forms 



will be filed first by latitude and second by longitude. 



2. Gulf Coast from longitude 84°00' to Mexico. In this file, the forms wiU be filed first 



by longitude and second by latitude. 



3. Pacific Coast, including Alaska and Hawaii. In this file, the forms will be filed first 



by latitude and second by longitude. 



Information for this file is obtained from: 



1. Corps of Engineers pubhcation "Bridges Over the Navigable Rivers of the United 

 States" (four parts) issued in 1961. 



2. Additional information (footnotes) in preliminary 1960 Corps of Engineers bridge lists 

 used to supplement item 1 . 



3. Corps of Engineers construction permits and final completion reports subsequent to 

 1961 bridge listings. 



