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El 10 de julio de 2024 salimos de Barbate (luz de la bocana del puerto). Sopla viento del este (E) que nos produce un abatimiento de 15º. Calcular el rumbo de aguja para pasar a cinco millas del faro de Punta Paloma. La declinación magnética de la carta es 4º W 2012 (5′ E) y el desvío de la aguja = +9º (más).On 10 July 2024 departing Barbate port entrance light with an East wind causing 15º leeway, calculate the compass course to pass 5 miles off Punta Paloma lighthouse (chart dm 4º W 2012 (5' E), deviation +9º):
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Correct answer: a) 128º
Why it is correct
From Barbate entrance (36º 11.3′ N, 005º 55.3′ W) the tangent to pass 5 miles SW of Punta Paloma lighthouse gives surface course Rs = 149º. With an East wind on the port side (+15º starboard leeway), steer 15º to port: Rv = 149º − 15º = 134º. In 2024 dm = −4º + (12 × 5′) = −3º; with deviation +9º, Ct = +6º and Ra = 134º − 6º = 128º.
Why the others are not
- b) Does not subtract the 15º starboard leeway or fails to subtract total compass error Ct = +6º.
- c) Does not subtract the 15º starboard leeway or fails to subtract total compass error Ct = +6º.
- d) Does not subtract the 15º starboard leeway or fails to subtract total compass error Ct = +6º.
How to work it out in the exam
- Draw from Barbate entrance the tangent 5 miles off Punta Paloma: Rs = 149º.
- Subtract 15º leeway (Rv = 134º) and subtract Ct = −3º + 9º = +6º: Ra = 128º.
Where this question comes from
- Junta de Andalucía · 2024 · 2ª convocatoria · PY Módulo de navegación · question 12 Official paper · Official answer key
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Pending instructor review. Machine translation, not reviewed.