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Finding DLAT And Departure

Find the DLAT and departure made good if a vessel steams for 1936 nautical miles on course 248° T.

Given:

  Course = 248° T
Distance = 1936 nm

What is asked?

Dlat and departure

Solution:

This kind of problem is of a Plain Sailing. What one has to bear in mind when speaking of a Plain Sailing is a plane triangle.

Plane Triangle

Solving For Difference in Latitude

   Cos 68° =    Dlat     
                   Distance 
         Dlat = Cos 68° × 1936 nm
         Dlat = 725.2 nm

Solving For Departure

    Sin 68° = Departure 
                     Distance
Departure = Sin 68° × 1936 nm
Departure = 1795 nm

Plain Sailing

3 comments:

  1. Where did the 68 come from.

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    Replies
    1. You have to convert from true to quadrant . since 248 degrees is in SW quadrant , quadrant bearing = true - 180 degrees <=> 248 - 180 = 68

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    2. And look at the plane triangle

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