July 2023 AM TCN
Q.1) At 2100 hrs, a ship observes the horizontal angle between Kingswear Light (500 21’N, 0030 34’W) and Start point Lt. (500 13’N, 0030 38’W) to be 500. It then steers a course of 2100 (T). At 2130 hrs, start point fixed Red Light was last visible. Find the ship’s position at 2130 hrs, assuming no current. From this position set course to have Channel Lt v/l (490 55’N, 0020 55’W) right ahead when 9 miles off with current setting 0300 (T) at 3 Kts. At what time would the Channel Lt. v/l be sighted right ahead.
Answer:
HSA between Kingswear Light and Start point Lt – 50° / Complementary angle – 40°
Drift=(Distance Off x Rate)/(Engine Speed) =(9×3)/12=2.25′
SMG=(AB × Rate)/Drift=(8.4×3)/2.25=11.2 Kts
2130 Position – 50°14.7’N; 003°30.6’W
Time – 2325 hrs Channel Lt/v will be sighted right ahead at 9’ off
Q.2) At 0800 hrs, Anvil Pt. Light House was 7 miles off and 0906 hrs. Bill of Portland Light was 8 miles off. Vessel steered 260°(T). Engine speed 9 Kts, during this interval. The current was setting 185°(T) at one knot. Find:
a) Ship’s position at 0800 hrs
b) Ship’s position at 0906 hrs
c) Course made good by her in this period.
Answer:
a) 0800 hrs Position: 50°29.2’N; 002°01.4’W
b) 0906 hrs Position: 50°26.4’W; 002°16.9’W
c) CMG – 254°T
Q.3) Plan a safe passage from Needles pilot boarding ground (50° 38’N, 001° 39’W) to Exmouth Pilots (50° 36’N, 003° 21.5’W). Way point/ courses/ distances are to be shown on the chart as well as on the answer sheets.
Plan the Passage as per question