For the past two nav problems, we have written about the 19th-century American master mariner, Captain “Bully” Samuels.
When we last left Captain Samuels, he had just won the very first transatlantic race in 1866 aboard the schooner Henrietta.
Captain Samuels was next aboard the schooner Dauntless. Four years after his transatlantic victory, Dauntless, with Samuels in command, raced across the Atlantic Ocean, from east to west against the English schooner Cambria.
The race began off Ireland on July 4, 1870. Cambria was owned by Sir John Asbury. Built by Michael Ratsey, Cambria, at 188 tons, was a powerful schooner, though with a mixed racing record. Asbury was bringing the schooner to New York to challenge for the America’s Cup. The smart money was on Dauntless yet Cambria crossed the finish line first winning by one hour, 43 minutes. The time was 23 days, 5 hours, 17 minutes.
It was not an easy race. On the third day out, Dauntless ran into a gale and two crew, Charles Scot and Albert Demer, were lost overboard while furling the jib.
In 1887, at 61 years old — an octogenarian by todays standards — Samuels once again took command of Dauntless, now owned by Cauldwell Colt, the son of Samuel Colt the gunmaker. He was racing against the more modern schooner Coronet only a couple of years old. Coronet won by more than 30 hours, but Samuels pushed Dauntless to reel off 328 nautical miles in one 24-hour period, a record that stood until the schooner Atlantic broke it in 1905.
The race was the third transAtlantic race and Samuels had competed in all three.
It is March 20. We will be using the 2023 Nautical Almanac. The DR of Dauntless is 34° 30’ N by 28° 10’ W. The height of eye is 15 feet. We’re doing a morning nautical twilight observation. We will be using HO 249 Volume I, Selected Stars.
In order to reduce the complications of the problem, I have already calculated the Ho from the Hs of each star. HO 249 Volume 1 is a great tool.
For the sake of this exercise, Captain Samuels observed three stars, Deneb, Antares, Alkaid. We’ll use the common time of 07 hours 0 minutes GMT. The Ho of Deneb is 46° 01.9’. The Ho of Antares was 29° 7.3’. HO of Alkaid was 52° 29.3’. For the sake of this exercise, we won’t include the correction for precession and nutation. n
A. Find the time of nautical twilight in GMT at sunrise.
B. Find LHA of Aries.
C. Find the intercepts and azimuths.
D. Plot the three star fix and find estimated position.