His Coordinates

“Navigation as a skill will be confined to leisure sailors”

Oct 2022 | No Comment

John Johnson-Allen

MA FRHistS FRIN MIoS, Chairman, Institute of Seamanship

Joining BP Tanker Co. as an an apprentice at the age of 16, he left as a Second Officer. He maintained his interest in the sea as a Royal Yachting Association lecturer for 22 years, teaching evening classes and also two years at Lowestoft College teaching Iranian excommandos technical English and seamanship.He sailed on the East Coast and from the Somme to the Scheldt for over 20 years, and, latterly, on the Norfolk Broads for 10 years. On retirement he took a Masters at Greenwich University in Maritime History, and has written five books and numerous articles for various maritime journals. He is a Liveryman of the Honourable Company of Master Mariners.

What is purpose of the Institute of Seamanship? Would you like to share some of the recent activities and the achievements of the institute?

The purpose of the Institute of Seamanship is to promote seamanship through education and training as a practical skill requiring knowledge, experience and common sense. The Institute encourages professional and amateur seamen to extend their seamanship skills and adopt sound seamanship practices. It advances the knowledge and practice of seamanship and supports research into seamanship, past present and future. Recently we have successfully changed the format of our journal from a printed edition to an online edition for members and have created a bursary for supporting young people in acquiring practical seamanship skills through on-board training on a sailing vessel.

You have extensive experience in marine navigation even of pre-GPS days. Would you like to share some of your experiences and the challenges of those days?

When I joined British Merchant Navy as a navigating apprentice in 1961 navigation was still little changed from the days of sail. The only electronic help was from the Decca Navigator hyperbolic radio chains, which were used for coastal navigation. All the deep sea navigation was by through the traditional use of astro navigation, using sextants, books of navigation tables and tables of astronomical ephemera, working out the positions by hand in a sight book. The pattern of sights for a 24-hour period was a star sight at dawn using the Marcq

St Hilaire formula, followed by obtaining a longitude in mid-morning using the sun and the longitude by chronometer formula, transferring the position line thus obtained to the latitude obtained from the noon sun sight which created the noon position from which the days run could be calculated. A further star sight was taken at dusk.

All this, of course, depended on the weather. If overcast, no sights could be taken and positions were estimated by using Dead Reckoning, using the ship’s course and speed to give an approximate position.

How do you see the impact of evolving navigation technologies in marine navigation? Do you think that the advent of satellite-based navigation has redefined the marine navigation?

The advent of satellite-based navigation transformed the position finding system of navigating a ship completely. In the days before, a position obtained by Astro navigation was accurate to probably a mile, sometimes a little less. Positions now, of course, are almost exact and unless clearly inaccurate, are accepted probably without question.

Do you think that with the increasing dependence on GNSS, how do you perceive the threats like interference, jamming and spoofing on marine navigation?

The threats arising from the almost complete dependence on satellite navigation are very real and with the souring of relations between the West and Russia, and the growing influence of China, the use of hacking techniques will, I believe become more sophisticated and a weapon more widely used. This might result in a return to astro naviagtion being taught as a backup. That cannot be hacked or interfered with.

You have taught coastal navigation to yachtsmen in pre-GPS days. What key challenges you perceive in the education of marine navigation?

The navigation I taught yachtsmen was for coastal navigation, using the traditional methods, using hand held magnetic compasses to obtain bearings, converted to true bearings, coupled with knowledge of tides to compute the tidal effect, and so working out a course to steer. This was taught in a classroom.

In my view the key challenge in the education of marine navigation is the preponderance of shore-based training. The sea time for navigating cadets in the British Merchant Navy is currently 12 months, out of a fouryear training course. Whilst simulators are invaluable, they cannot compete with real shipboard experience in real sea time.

Would you like to convey any message to marine navigators?

Looking into the future, with the potential for unmanned ships looming, the role of the marine navigator as a distinct profession will change as ships are remotely controlled. The role of the navigator will be confined to be shore based, providing and operating the software to navigate the ships of the future. Navigation as a skill will be confined to leisure sailors.




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