Oct 2024 AM TCN
Q.1) While steering a course of 092°(C). A vessel last sights Kullagrund White light (55°17’N 013°20’E) on the port beam when meteorological visibility was 2 miles only. Find the vessel’s position. After 2 hrs of steaming observed position was 55°14.9’N 014°03.5’E. Find:
a) Set and rate of current
b) Compass course to steer to pass Sandhammeren light (55°24’N 014°12’E) 3 miles on the port side.
c) time when Sandhammeren light will be first sighted. Assume visibility and current to be same throughout
Answer:
Geographical Range of Kullagrund Lt = 2.095√18+2.095√15 = 17 nm
Present Luminous range of Kullagrund Lt = 5.1 nm
Geographical Range of Sandhammeren Lt = 2.095√31+2.095√15 = 19.8 nm
Present Luminous range of Sandhammeren Lt = 6.4 nm
Course – 092° (C)
Var – 1°W
Dev – 12.3°W
True Course – 078.7°T
Bearing of Kullagrund Lt – 348.7°T
a) Set – 173° / Rate – 1.4 kts
b) Compass CTS – 056.3°(C)
c) 02 hrs 17 mins Sandhammeren light will be first Sight
Q.2) A v/l steering a westerly course observes Utklippan Lt. (55° 57’N, 15° 41’E) at a bearing of 057°(T) and 8’ off. After running 16 miles by engines on her course Hano Lt. Gp fl (56°01’N, 14°51’E) bore 328°(T) and after running another 8’ by engines, it bore true north.
Find: a) Vessel’s position at the time of final bearing
b) Course and speed made good
c) Set and rate of current.
Answer:
a) Vessel Position at Final Bearing – 55°47.5’N; 014°50.7’E
b) CMG – 255°T / SMG – 11.9 Kts
c) Set – 159°T / Rate – 3.05 Kts
Q.3) At 1830 hrs, a vessel in DR 55°45’N 016°30’E took simultaneous observation of two stars, Star X brg 280°(T) intercept 2 miles away Star Y brg 230°(T) intercept 3 miles towards. Find the position of the vessel and from this position find the course to steer at 12 knots so that Olands Sodra Grund light will be right ahead when 10 miles off, contracting current setting 260° at 3.6 knots. What time would you expect the light to be right ahead. Later it so happened that light was right ahead 10 miles off at 1945. What was the actual current experienced by the vessel.
Answer:
1830 Position: 55°39.2’N; 016°32’E
CTS that Olands Sodra Grund Lt will be right ahead – 022°T
Time that Olands Sodra Grund Lt will be right ahead – 1959 hrs
Actual current Experienced if that light was right ahead at 1945 hrs – 292°Tx3.6’