Hover or tap underlined Spanish terms to see their translation and exam tip.
Zarpamos del puerto de Barbate (desde la luz roja de la bocana) con rumbo de aguja = 150º y velocidad del buque = 7 nudos (variación local o declinación magnética= 2º NW y desvío de la aguja= +2º). Calcule a qué distancia estaremos del faro de Punta de Gracia una hora más tarde:Departing Barbate port (from the entrance red light) on compass course Ra = 150º at 7 knots (variation 2º NW, deviation +2º), how far will you be from Punta de Gracia lighthouse 1 hour later?
Show the answer
Correct answer: c) 2.3 miles
Why it is correct
With variation −2º and deviation +2º, total compass error is Ct = 0º and Rv = 150º. Running 1 hour at 7 knots (7 miles) along 150º from Barbate red light (36º 11.3′ N, 005º 55.3′ W) reaches 36º 05.2′ N, 005º 51.0′ W, which is 2.3 miles from Punta de Gracia lighthouse (36º 05.4′ N, 005º 48.6′ W).
Why the others are not
- a) Does not match the distance from the point reached after 7 miles on 150º to Punta de Gracia.
- b) Does not match the distance from the point reached after 7 miles on 150º to Punta de Gracia.
- d) Does not match the distance from the point reached after 7 miles on 150º to Punta de Gracia.
How to work it out in the exam
- With Ct = −2º + 2º = 0º, plot 7 miles along Rv = 150º from Barbate breakwater.
- Measure the distance from that point to Punta de Gracia lighthouse: 2.3 miles.
Where this question comes from
- Región de Murcia · 2018 · 2ª convocatoria · PER Tipo 1 · question 43 Official paper · Official answer key
Try it: Navigation calculations
Pending instructor review. Machine translation, not reviewed.