Hover or tap underlined Spanish terms to see their translation and exam tip.
A HRB = 10 00 del 16 de noviembre de 2024 nos encontramos en situación 35º 50′ N, 006º 08′ W. Navegamos a 6 nudos al rumbo de aguja 085°. Calcular la h m situación de estima a HRB = 12 30 . Declinación magnética = 4° NW y desvío de la aguja = –8° (menos).At ship’s clock 10h 00m on 16 November 2024 we are at 35º 50′ N, 006º 08′ W. We sail at 6 knots on compass course 085°. Calculate the dead reckoning position at 12h 30m. Magnetic variation = 4° NW and compass deviation = –8° (minus).
Show the answer
Correct answer: a) 35º 54.4' N; 005º 50.4' W
Why it is correct
Total correction = −4º − 8º = −12º, so true course = 085º − 12º = 073º. 2.5 h at 6 knots is 15 miles: 4.4′ north and 14.3 miles east, which is 17.7′ of longitude.
Why the others are not
- b) The working gives 35º 54,4′ N, 005º 50,3′ W, and this option does not match.
- c) The working gives 35º 54,4′ N, 005º 50,3′ W, and this option does not match.
- d) The working gives 35º 54,4′ N, 005º 50,3′ W, and this option does not match.
How to work it out in the exam
- Find the true course: true = compass + total correction.
- Distance = speed × time.
- Draw the course on the chart, measure the distance and read the position.
Where this question comes from
- Junta de Andalucía · 2024 · 3ª convocatoria · PER Modelo A · question 42 Official paper · Official answer key
- Junta de Andalucía · 2024 · 3ª convocatoria · PER Modelo B · question 44 Official paper · Official answer key
Try it: Navigation calculations
Pending instructor review. Machine translation, not reviewed.