Hover or tap underlined Spanish terms to see their translation and exam tip.
A las 08h 00m del 25 de marzo de 2023, nos encontramos en situación verdadera 36º 10,0' N, 006º 10,0' W. Navegamos a 8 nudos al rumbo de aguja 155º, en ausencia de viento y corriente. Calcular la situación de estima a las 09h 30m, sabiendo que la declinación magnética es 2° NW y que el desvío es +9° (más).At 08h 00m on 25 March 2023 we are at true position 36º 10.0' N, 006º 10.0' W. We sail at 8 knots on compass course 155º, with no wind or current. Calculate the dead reckoning position at 09h 30m, given that magnetic variation is 2° NW and deviation +9° (plus).
Show the answer
Correct answer: b) 35º 58.5' N; 006º 05.4' W
Why it is correct
Total correction = −2º + 9º = +7º, so true course = 155º + 7º = 162º. 1.5 h at 8 knots is 12 miles: 11.4′ south and 3.7 miles east, which is 4.6′ of longitude.
Why the others are not
- a) The working gives 35º 58,6′ N, 006º 05,4′ W, and this option does not match.
- c) The working gives 35º 58,6′ N, 006º 05,4′ W, and this option does not match.
- d) The working gives 35º 58,6′ N, 006º 05,4′ 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 · 2023 · 1ª convocatoria · PER Modelo A · question 43 Official paper · Official answer key
- Junta de Andalucía · 2023 · 1ª convocatoria · PER Modelo B · question 42 Official paper · Official answer key
Try it: Navigation calculations
Pending instructor review. Machine translation, not reviewed.