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Nos encontramos sobre la línea de la enfilación de los faros de Punta Cires y Punta Alcázar y tomamos demora de aguja a dicha enfilación = 235º y distancia al faro de Punta Cires = 5 millas. Desde esta posición, damos rumbo de aguja = 038º, teniendo en cuenta que nos afecta una corriente de Rcte: 075º y Vhc= 3 nudos. Velocidad del buque (Vb)= 8 nudos. Calcular el rumbo efectivo que llevamos:Observing Da = 235º at 5 miles from Punta Cires on the Punta Cires–Punta Alcázar leading line, you steer Ra = 038º at Vb = 8 knots in a current setting 075º at 3 knots. Calculate your effective course:
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Correct answer: a) 041º
Why it is correct
The charted true bearing of the Punta Cires–Punta Alcázar alignment is Dv = 227º; since Da = 235º, total compass error is Ct = 227º − 235º = −8º. Thus true heading is Rv = 038º − 8º = 030º (Vb = 8 knots). Vector-adding the current (Rc = 075º, Vhc = 3 knots) yields effective course Ref = 041º.
Why the others are not
- b) Does not obtain Ct = −8º from the leading line or fails to vector-add (030º, 8 kn) with (075º, 3 kn).
- c) Does not obtain Ct = −8º from the leading line or fails to vector-add (030º, 8 kn) with (075º, 3 kn).
- d) Does not obtain Ct = −8º from the leading line or fails to vector-add (030º, 8 kn) with (075º, 3 kn).
How to work it out in the exam
- Find Ct from the Cires–Alcázar alignment (Dv = 227º, Da = 235º ⇒ Ct = −8º) and convert to Rv = 038º − 8º = 030º.
- Add the ship vector (030º, 8 kn) and current vector (075º, 3 kn): Ref = 041º.
Where this question comes from
- Región de Murcia · 2024 · 2ª convocatoria · PY Tipo 1 · question 37 Official paper · Official answer key
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Pending instructor review. Machine translation, not reviewed.