Sir Ernest Shackleton’s Antarctic expedition
vessel Endurance was recently found deep in the Weddell Sea.
It’s a famous marine survival story. How a courageous band of brothers survived the loss of their ship thousands of miles from all help. How Sir Ernest Shackleton and his crew persevered, establishing the template for surviving harsh conditions.
In March of this year their ship, Endurance, was located 10,000 feet deep in the Weddell Sea in a remarkable state of preservation.
Even before Roald Amundsen had reached the South Pole in 1912, Sir Ernest Shackleton had contemplated another Antarctic effort. The Trans-Antarctic expedition; a sled journey across the continent. The plan was to take the ship Endurance into the Weddell Sea and drop off a sledding team of six men and 70 dogs. Another ship, Aurora, would be on the other side of Antarctica setting food caches. The team would bring their own food halfway and then pick up the caches after that.
His ship of choice was originally named Polaris and renamed Endurance after Shackleton’s family motto: fortitudine vincimus, or by endurance we conquer. A 144-foot three-masted barquentine with a 25-foot beam it was built in 1912 in Norway. Before completion the owners ran out of money and Shackleton got it at a bargain price.
After departing England on August 6, 1914 (Britain had declared war on Germany on August 4), Endurance arrived in Buenos Aires in October. From there they sailed to South Georgia Island and a month later, the ship left for Antarctica and the Weddell Sea, getting stuck in the ice on January 24, 1915. Endurance drifted in the ice pack in a westerly direction until it was crushed in the ice and sank on November 21 at 1650 local time.
According to Frank Worsley, the navigator and captain, the ship sank at 68° 38.5’ S by 52° 28’ W. Endurance was found just four miles south of this.
Let’s join Endurance on October 29, 1914, on its way to South Georgia Island. Its DR is S 39° 05’ by W 34° 24’. The height of eye is 20 feet. Worsley has calculated civil twilight at 21:20 GMT. We will use the 2022 Nautical Almanac and Volume I of the Selected Stars Sight Reduction Table. Worsley took three star sights: Diphda with an Hs of 44° 10’; Rigil Kentauris with an Hs of 27° 42’; and Altair with an Hs of 36° 28’. For simplicity sake, we will use the same time for all the sights as the time of Civil Twilight, 21:20 GMT.
A. Find the LHA of Aries for that time.
B. What is the HO of Diphda, what is intercept & Zn?
C. What is Ho of Rigil Kent., what is intercept & Zn?
D. What is Ho of Altair, what is intercept & Zn?
Answers:
A. LHA Aires 324°
B. Diphda Ho is 44° 0.47’; intercept is 3.3 nm away at 076°.
C. Rigil Kent Ho is 27° 35.9’; intercept is 11.9 nm toward at 212°.
D.Altair Ho is 36° 22.4’; intercept is 4.4 nm toward at 327°.076°.