With the outbreak of World War II, Canada and the U.S. established naval bases in Labrador and Newfoundland. One of the largest of these was the Naval Air Base at Argentia, Newfoundland.
On Feb. 17, 1942, USS Pollux, a Navy cargo vessel carrying valuable war supplies was en route from Maine to Argentia, escorted by the destroyers USS Truxtun and USS Wilkes. The crew on Truxtun was young and inexperienced, many having just enlisted after the Japanese bombing of Pearl Harbor in December of 1941. They were getting their sea legs in dangerous waters around Nova Scotia.
It was a lousy time of year to be shipping supplies to Newfoundland. The North Atlantic in winter was not an area to be trifled with. Winter gales whipped these coasts with immense power.
On that February night though, the winter gale had reduced visibility to zero and the lowered temperatures and boarding waves soon had the decks covered in ice. With the ships steaming together, collision was a risk. Because of imposed radio silence between the vessels, all communications were done via flares using Very pistols — not the most effective means of communication. To add to the problems, Navy orders required them to zigzag to avoid U-boat attacks.
As flagship, USS Wilkes set the course and the others followed suit. Navigator Lieutenant Arthur Barrett set out a DR based on a star sight he made on Antares at 0923 GMT that morning. His shot was slightly in error, causing him to calculate the ship’s LOP about 2.5 miles south of its actual location.
As a result of that imprecise LOP, all three ships were closer to shore than they had anticipated.
Aboard Pollux, navigator Lieutenant William Grindley noticed the error in the plot and advised the skipper Commander Hugh Turney that they should alter course 30 degrees to starboard. After much hesitation, the skipper only agreed to a 10-degree course change.
Truxtun ran aground in St. Lawrence, Newfoundland, and 110 souls were lost. The people of St. Lawrence made a heroic rescue of the remainder of the men, risking their lives. The Wilkes and Pollux also ran aground with less loss of life.
Let’s join Lt. Barrett as he scrambles to grab a shot of Antares on a miserable sea-swept morning in February. The day is Feb. 17 and we are using the 2014 Nautical Almanac. We’ll use a height of eye of 30 feet. We are at a DR of 47° 06’ N by 53° 47’ W.
Barrett would have used the Rude star finder to locate the azimuth and approximate altitude of Antares. At nautical twilight he snaps a shot of the star with Hs of 16° 19.6’. There is no index error and the time of the observation is 0949:20 GMT. Although he was using HO 229 or HO 214 at the time, we will use HO 249 sight reduction tables volume 3 to find the intercept of Antares.
A. What time is Nautical Twilight?
B. What is the Ho?
C. What is intercept?
A. Nautical Twilight starts between 0555 and 0558 LMT
B. Ho is 16° 11’
C. Intercept is 9 nm away