Editor’s note: This nav problem is based on reporting on Juan Manuel Ballestero’s voyage by Daniel Politi in The New York Times. Ballestero’s thought process is David Berson’s own speculation.
Juan Manuel Ballestero, a 47-year-old sailor, had a problem. He was aboard his Ohlson 29 sailboat, Skua, on the small island of Porto Santo off the coast of Portugal but he wanted to get home to Argentina to celebrate his father’s upcoming 90th birthday. Ordinarily, Ballestero would have secured his boat, hopped on a plane and been with his father.
As a result of COVID-19, however, all flights departing Portugal to Argentina were canceled. So, what was he to do? He could have called his father and sent his best wishes, but his father was the man who had captained fishing boats and taken Juan, as a 3-year-old, out on a boat for the first time. This was a father who had shaped his son’s love of the sea, from fishing off Patagonia to sailing over many of the world’s oceans — a call wasn’t enough. There was always his boat, Skua. Why not sail back to Argentina? With a 24-foot waterline, Skua wasn’t going to go much faster than 6 knots; Ballestero figured he would need about 75 days of provisions (it took 85 days).
To add to the uncertainty, Ballestero was informed by Portuguese authorities that he might not be allowed to return should he run into trouble. Ballestero had sailed many miles on his boat from Sri Lanka to Alaska, and he knew he was up to the task. Provisioned with extra fuel, water, tuna fish, fruit and rice, Ballestero departed the island of Porto Santo in mid-March.
In early April, he was approaching the Cape Verde Islands at about 16° N, but customs refused him permission to enter. A very harsh decision, but Ballestero was determined and decided to carry on. He would have to be mindful of his supplies, but he wasn’t going to be thwarted. He struggled with his loneliness but was quoted as saying, “This voyage gave me lots of humility.”
When Ballestero finally arrived at his home port of Mar del Plata on June 17, he received a hero’s welcome. He took a test for COVID-19, which returned negative 72 hours later, and he was allowed onto Argentine soil. He missed his father’s birthday, but they did celebrate Father’s Day.
With no information about his navigation skills, let’s assume Ballestero used celestial nav. Let’s also assume Ballestero took noon shots to confirm his latitude. From a noon line of position, an EP can be calculated that can be compared to a GPS position, if needed.
On May 16, Skua is at a DR of 23° 25’ S by 45° 15’ W. The height of eye is 19 feet and there is no index error on the sextant. We will be observing the sun’s lower limb. The Hs is 47° 05’.
A. What is time of LAN in GMT?
B. What is the Ho?
C. What is noon latitude?
D. Calculate EP from the plot.
A. LAN is 14:57
B. Ho is 47° 17’
C. Latitude is 23° 25’ S
D. EP is essentially same as DR