78 NAUTICAL CHART MANUAL 



All aids to navigation along dredged channels shall be charted in their true positions when 

 being plotted oi* revised on Drawings or Aid Proofs, unless such aids on opposite sides of a 

 channel plot less than 1.5 mm. apart. In this case the aids may be separated to L5 mm. if the 

 approval of the Chief of Branch is obtained. At this separation, daymarks will barely overlap. 

 However, aids shall not be moved off ranges or natural objects. The overlap of magenta discs 

 is not considered detrimental to the clarity of the chart. Any lettering or sounding within the 

 disc shouldbe moved to clear it except a critical sounding which shall not be moved. 



It will not be necessary for cartographers to investigate the charted positions of channel 

 aids in those areas not being revised from new source material unless the Aid Proof indicates 

 that this should be done. 



Fixed aids are often built on rocks and isolated features, and care must be taken to restore 

 these features when- the aids are removed from the charts. 



Before being sent to the Reproduction Division, all new or corrected charts must be sub- 

 mitted to the Aids Section for checking of aids. After all the necessary work has been accom- 

 plished in the Reproduction Division and the chart is ready for printing, a final check of aids 

 is made, at which time a check must be made of the printing date. This printing date should be 

 a Monday following the date of the last Notice to Mariners applied. The Coast Guard Head- 

 quarters, Aids to Navigation Division, is contacted at this time for knowledge of proposed 

 navigational aid projects with approximate dates of completion within the chart limits in order 

 to coordinate the printing supply and completion of major revisions. 



Temporary defects in aids to navigation are not indicated on the charts except where 

 a buoy replaces a fixed aid. A standard note covering this practice is added to all charts. 

 (See Fig. 9.) When a buoy replaces a fixed aid, the following abbreviations are added at 

 the fixed aid by a hand correction in red : 



TRLB Temporarily replaced by lighted buoy showing the same characteristic 



TRUB Temporarily replaced by unlighted buoy 



TLB Temporary lighted buoy 



TUB Temporary unlighted buoy. 



LIGHTS (Figs. 1, 19, 20, 24) (K) 



The positions of aU fixed lights shall be shown on Drawings by the intersection of two red 

 lines parallel to the neatlines, and on Compilations by similar intersecting blue lines. On charts, 

 a lighted beacon or lighthouse is represented by a black dot, 0.76 mm. in diameter, and over- 

 printed by a magenta disc, 3.0 mm. in diameter. 



On all Drawings and Compilations, the cartographer shall indicate the size of the magenta 

 discs for lighted aids to navigation by drawing a non-photographic blue-ink circle on the 

 Compilations and a green-ink circle on Drawings, using the standard diameter at each position. 



