NAVIGATIONAL HINTS 



found to be valuable in crowded anchorages. 



A chart, preferably an anchorage chart of the area is prepared in 

 the following manner: 



Three or four prominent points or objects, preferably good radar 

 targets, which give a coverage of the entire anchorage area as well as 

 furnishing the widest possible angles of bearing are selected. From 

 these selected points lines of position are drawn at 1-degree intervals 

 covering the entire anchorage area, using a different colored ink for 

 the lines drawn from each point or object. The bearing lines are 

 extended beyond the anchorage area and the true bearing from the 

 objects or targets marked on the extremities of the lines. Upon 

 assignment of an anchorage berth, range lines in any desired incre- 

 ments are laid down in arcs with pencil from the selected points to 

 the assigned berth. The prepared chart is now ready for use, overlaid 

 with inked lines of position from the selected objects for bearing pur- 

 poses and penciled arcs in the vicinity of the assigned berth for 

 ranging purposes. 



As the vessel approaches the assigned berth instantaneous fixes 

 may be obtained, as rapidly and frequently as desired, merely by 

 noting the bearings as the observer at the bearing circle gives them 

 to the navigator at the prepared chart. The navigator simply marks 

 the ship's position where the bearing lines cross. The radar ranges 

 are also given at the same time as a further check on the ship's posi- 

 tion. By setting a universal drafting machine or parallel rules on 

 the ship's course line and placing same on latest fix any course changes 

 are immediately apparent. A further refinement could be made by 

 placing red-penciled range rings in increments of 100 yards from the 

 center of the assigned anchorage berth in order to rapidly read off 

 the remaining distance to the berth. 



This method requires a navigation staff normally found on board 

 a naval vessel. It may, however, be useful to the merchant navigator 

 when assigned to a congested anchorage berth. It could also be used 

 by a vessel regularly running a congested channel or restricted man- 

 euvering area for obtaining positions, requiring only a minimum 

 amount of time in the chartroom. 



Simplified chart shows only bearing limits passing through desired 

 anchorage. In practice, bearing lines at I'degree intervals would be drawn 

 from selected landmarks in different colors and marked at their extremities. 

 Range circles, at suitable scale, would be drawn from center of arwkorage to 

 indicate distance remaining. 



CONCLUSION 

 When one stops to consider that the art and science of navigation 

 are a coalescence of astronomy, cartography, mathematics, geography, 

 history and man's unquenchable desire to explore the unknown, it is 

 easy to see that the skillful mariner must have a tremendous reservoir 

 of facts, hints and common sense to fulfill his mission. The Oceano- 

 graphic Office endeavors to assist the mariner in every possible field 

 of safe navigation and solicits the mariner's comments and sugges- 

 tions for the improvement of its products in a mutually beneficial 

 program of maritime safety. 



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