Unfortunately,  as the founder and busy principal of a sailing school on the Isle of Man and RNLI volunteer on the Port St Mary lifeboat, she ran out of time before the voyage and realised internet access in mid Atlantic was impractical.

So, armed with a donated plastic sextant, three text books, torch, watch, chart, dividers, calculator and a supply of pencils and plotting sheets she decided to teach herself during the crossing from the Canaries to the British Virgin Isles on board a 47 foot catamaran. That was alongside her duties on board, such as provisioning, checking equipment, planning, navigating and organising the duty watch system that were essential for her desired qualification as a Yachtmaster Ocean.

"I hadn't gone far enough in the on-line learning before I left," said Jen, "but fortunately I had been given a couple of books by a former merchant navy captain, though one was an old maths-based one."

The boat was equipped with radar, GPS and autopilot so could steer itself all the way but Jen settled down with her two favourite books, Sailing by the Stars by Paul Rodgers and Celestial Navigation by Tom Cunliffe to unpick the mysteries of the sextant and its attendant calculations. "The best bit of advice was 'just pick up the sextant and start taking sights'." 

She started the voyage with visual fixes until losing sight of Gran Canaria, then switched to dead reckoning, using the speed, time and direction.

As she explains in her very entertaining blog (http://carreybeayn.com), the boat was not rigged for speed, so there would be plenty of time to study her astro navigation. She moved on with her navigation to use the sun, checking its angle  above the horizon at regular intervals starting 20 minutes before the anticipated local noon and continuing until the readings started to decrease. "Noon is not at noon," she notes, adding that the Admiralty Almanac supplies answers to that.

Checking her calculations against the GPS instruments, Jen was able to track down some errors in her workings, gradually improving their accuracy until she felt confident enough to use her sextant with the night skies, using moon, planet and star sights.

Jenni up the mast in a bosun's chair to put protection on the spreadersShe still had all her watch-keeping and other duties: Power problems in mid Atlantic when the batteries were losing charge faster than expected were a reminder why traditional navigation needs to sit alongside GPS. When she spotted chaffing making a hole in the main sail, it fell to her to ascend the mast in a bosun's chair and wrap protection around the spreaders to stop them rubbing on the fabric.

Her intention on reaching Antigua had been to start a winter job there, but the devastation of Hurricane Irma had messed up those plans. Nevertheless, 24 days after setting out she reached her destination and immediately set about finding a suitable examiner.

He interviewed her, asked for all her logs and other documents and booked her in for an examination the following morning. It was a tight window as she was due to fly back to the UK in the afternoon.

Fortunately all the practical experience had reinforced her book-learnt navigation and as the taxi to the airport arrived, her paper had been marked and she was handed a sealed envelope to bring back and post in the UK, so she could get her newly-earned qualification from RYA headquarters.