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A HRB = 15:00 nos encontramos en la oposición de los faros de Isla de Tarifa y Punta Cires y simultáneamente Demora verdadera al Faro de Punta Carnero = 032º navegando al Rumbo verdadero = 070º y velocidad del buque = 8 nudos con Viento del NORTE que nos produce un abatimiento de 15º. Calcular la situación al estar al través del faro de Punta Almina.At HRB 15:00 on the Isla de Tarifa–Punta Cires opposition with Dv Punta Carnero = 032º, you steer Rv = 070º at 8 knots with a North wind causing 15º leeway. Calculate your position when abeam of Punta Almina lighthouse:
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Correct answer: c) 035º 57.6' N 005º 17.2' W
Why it is correct
The start (Tarifa–Cires opposition with Dv Carnero = 032º) is 35º 55.6′ N, 005º 30.9′ W. With Rv = 070º and a North wind on the port side (+15º starboard leeway), surface course is Rs = 070º + 15º = 085º. When Punta Almina lighthouse is abeam to starboard (90º from true heading Rv = 070º), true bearing to Almina is Dv = 070º + 90º = 160º (reciprocal 340º from Almina), which intersects Rs = 085º at 35º 57.6′ N, 005º 17.2′ W.
Why the others are not
- a) Takes the perpendicular to the surface track instead of abeam relative to the ship's head (Rv = 070º).
- b) Takes the perpendicular to the surface track instead of abeam relative to the ship's head (Rv = 070º).
- d) Takes the perpendicular to the surface track instead of abeam relative to the ship's head (Rv = 070º).
How to work it out in the exam
- Plot the start (35º 55.6′ N, 005º 30.9′ W) and draw the surface track Rs = 070º + 15º = 085º.
- Intersect with the abeam bearing relative to heading (Dv = 070º + 90º = 160º, reciprocal 340º from Almina): 35º 57.6′ N, 005º 17.2′ W.
Where this question comes from
- Junta de Andalucía · 2017 · 2ª convocatoria · PY Módulo de navegación · question 11 Official paper · Official answer key
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Pending instructor review. Machine translation, not reviewed.