Voyaging couple led the way

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Eric and Susan Hiscock were the most famous of the cruising couples who popularized ocean voyaging as a lifestyle. They were also the first ones who were able to make that lifestyle financially viable through their writing and lecturing. Beginning their first circumnavigation in 1952, they circumnavigated twice more during the next 25 years.

They wrote more than 12 books and became a source to generations of sailors.

Both were born on the Isle of Wight, England. Born in 1908, Eric’s first boat was a wooden, gaff-rigged, 18-foot sloop built in 1890. It was named Wanderer and for as long as he sailed that was the name that he gave to all his boats. Eric enjoyed the boat so much that he approached the young Laurent Giles to have him design a 25-foot wooden sloop. Unfortunately, Hiscock couldn’t afford to have the boat built so Giles cut down the size of the boat and Hiscock built a 21-foot version. It was on that boat, Wanderer II, that Eric and his new bride, Susan, took their honeymoon trip to the Azores and then cruised the coast of Spain and France.

Eric had been in the Royal Navy for two years during World War II when he was discharged because of bad eyesight. He was informed by a commanding officer that he “was half blind.” It was because of his poor eyesight that his cruises before the war were short &mdash navigation was difficult, but when he met and married Susan all that changed. “I realize now,” he wrote later, “that I have married the perfect crew.” They enjoyed voyaging so much, they went back to Giles and had him draw lines for a 30-foot marconi-rigged sloop called Wanderer III. On this vessel they installed a 4-hp diesel and a fuel tank that gave them a 50-mile range.

It was aboard Wanderer III that the Hiscock’s spent the next 17 years circumnavigating the globe twice becoming the first couple to accomplish that feat. Eric equipped both Wanderer III and his next boat, the steel Wanderer IV, with a darkroom in the forepeak.

They departed England for that first circumnavigation in 1952. By this time they had already sea trialed Wanderer III by seeking out the worst weather conditions along the English coast. From there they sailed on to the Panama Canal and the Pacific Ocean. They arrived back on Isle of Wight three years later. Eric then wrote the classic Around the World in Wanderer III.

Eric Hiscock passed away aboard Wanderer V in New Zealand at age 78 in 1986. Susan returned to the Isle of Wight, bought a small cottage, living ashore until her own passing in 1995. She was so extraordinary that she won her first small boat sailing race when she was 78 years old.

Let’s join the intrepid couple aboard Wanderer III running down the trades on December 10 (we’ll use the 2009 Nautical Almanac), on the way to the West Indies. The DR is 18° 15′ N by 57° 14.5′ W. Height of eye is 10 feet and there is no index error on the sextant. Eric Hiscock is going to take advantage of a sunrise moon shot. The time of the sight is 09:12:10 GMT. He will shoot the upper limb of the moon. The Hs from his resulting shot is 55° 32.8′.

A. What is the Ho?

B. Find the intercept.

C. Plot and find the Estimated Position.

Long solution for ON 183 Hiscock moon observation

David Berson

A note: My celestial navigation mentor and good friend, Eben Whitcomb, pointed out my confusing use of language in describing this problem. I did not intend to suggest that the moon was rising at sunrise-only that it was suitable for an observation at sunrise when a working horizon became available.

Traditionally, the moon shot was considered the sine qua non in the navigator’s arsenal. The process of reducing a moon shot, was complicated and fraught with the potential for mistakes. Since the advent of the compressed moon tables at the rear of the Nautical Almanac, many of those difficulties have been obviated. Despite these improvements, the moon observation still sends celestial navigators into paroxysms of concern. Truth be told though, the moon is easy to shoot, and the reduction tables, if followed carefully, are no more difficult to understand than any of the other tables in the Almanac. The moon presents an easy target and can be used at certain periods of the month to obtain a fix along with a sun sight.

As expert navigators, the Hiscocks were aware of this and took advantage of a moon observation. For all aspiring navigators I highly recommend this sight. After a few times the reduction will become almost as simple as a sun sight.

The day in question is December 10, (2009 NA). The DR is 18° 15′ N by 57° 14.5′ W. The height of eye is 10 feet and there is no index error. The time of the sight is 09:12:10 GMT. Hiscock is taking an upper limb and the resulting Hs is 55° 32.8′. We need to find the Ho, the intercept and the Estimated Position.

GHA @ 9 hrs 30° 54.3′ v 12.6′ Dec S 6° 54.1′ d +14.3 HP 57.9
+ 12:10 2° 54.2′ + 3.0′
+ v corr 2.6′ S 6° 57.1′
GHA 33° 51.1′
GHA 393° 51.1′
– ass long – 57° 51.1′
LHA 336°

All the above information is gleaned from the daily moon pages and then the increments and corrections tables at the rear of the NA for the minutes after the hour of the sight. Just look up the corresponding v and d corrections. The v correction is always added to the GHA and the d correction for declination can either be added to, or subtracted from, the declination depending on whether the declination is increasing or decreasing. This is ascertained by examination of the tables for the moons declination.

Hs 55° 32.8′
dip -3.1′
Ha 55° 29.7′

From here go to the moon table at the rear of the NA and look for column that includes apparent correction tables for 55°. Follow the instructions for the corrections for refraction and parallax and semi-diameter (all inclusive).

Ha 55° 29.7′
+ 42.7′
+ 3.7′
Ho 55° 46.1′

Note: When an upper limb shot is taken 30′ is subtracted in order to get the Ho. This is specified in the instructions.

Now that we have the Ho the assumed longitude, the LHA and the assumed latitude, in this case 18° N, we can enter into HO 249 Vol. 2

The declination of the moon is Contrary to the latitude of the observer so we have the following:

Hc 56° 17′ d –43 Z 133°
Table 5 -41′
Hc 55° 36′

Remember that Table 5 corrects for the minutes of declination that have to be factored into the whole degree of declination
We have, then, the following:
Ho 55° 46.1′
-HC 55° 36.0′
Intercept 10.1 nm Toward

Remember when HO is greater than Hc the position of the observer is closer to the GP of the celestial object.

The remaining part of the problem is the graphical solution of the numbers. I laid out a universal plotting sheet and plotted the LOP and arrived at an estimated position of 18° 21′ N by 57° 22′ W.

By Ocean Navigator