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A las 14h 30m del 6 de abril de 2024, nos encontramos en situación verdadera 36º 08,0' N, 006º 13,0' W. Navegamos a 6 nudos al rumbo de aguja 116°. Calcular la situación de estima a las 16h 45m, sabiendo que el desvío de la aguja es –8° (menos) y que la declinación magnética es 5º NW.At 14h 30m on 6 April 2024 we are at true position 36º 08.0' N, 006º 13.0' W. We sail at 6 knots on compass course 116°. Calculate the dead reckoning position at 16h 45m, given that compass deviation is –8° (minus) and magnetic variation 5º NW.

Show the answer

Correct answer: c) 36º 04.9' N; 005º 56.8' W

Why it is correct

Total correction = −5º − 8º = −13º, so true course = 116º − 13º = 103º. 2.25 h at 6 knots is 13.5 miles: 3.0′ south and 13.2 miles east, which is 16.3′ of longitude.

Why the others are not

  • a) The working gives 36º 05,0′ N, 005º 56,7′ W, and this option does not match.
  • b) The working gives 36º 05,0′ N, 005º 56,7′ W, and this option does not match.
  • d) The working gives 36º 05,0′ N, 005º 56,7′ W, and this option does not match.

How to work it out in the exam

  1. Find the true course: true = compass + total correction.
  2. Distance = speed × time.
  3. Draw the course on the chart, measure the distance and read the position.

Where this question comes from

Try it: Navigation calculations

Pending instructor review. Machine translation, not reviewed.