The little ship with the huge responsibility

This year was a poignant one for the D-Day veterans as 2019 marked three-quarters of a century since the momentous event. A lifetime’s span has passed since over 250,000 young men attacked German forces on the coast of Normandy, France, and gained a victory that became a turning point for WW2 in Europe. 

Evolution Capital will be hosting an informal lunch and networking event on August 16 onboard HMS Medusa, the iconic 1943 Harbour Defence Motor Launch renowned for being one of the ‘ships that saved D-Day’ thanks to her crucial role marking the minefield off Omaha Beach.

Business owners in the telecoms sector will learn how Medusa’s pioneering navigation technology was used to save thousands of lives during WW2. Her story is a formidable example of courage, technological innovation and meticulous planning. 

The history

On 5 June 1944, the day before D-Day, HDML 1387, later named HMS Medusa, left the south coast of England to play her pivotal role in the landings. She and her nine sister vessels, of the same make and manufacture, were to take up their positions, well within striking distance of enemy guns, and mark out 10 safe channels for the allied invasion fleet. 

Had they failed in their collective mission, the success of D-Day would have been severely compromised and perhaps even aborted. There were, of course, countless acts of heroism and valour during the operation itself by air, land and sea but before the first allied company could set foot on the beaches, Medusa had a vital task to perform.

The first HDML (Harbour Defence Motor Launch) was built in 1939 and designed to form an offshore screen against submarine attacks. During WW2, there were 464 of the vessels built, but by the time D- Day was being planned the threat had diminished and their future role in the conflict was redefined. 

Part of what became collectively known as ‘Churchill’s Pirates’, Medusa was well armed with twin 20mm Oerlikon deck guns, twin Vickers K machine guns and six depth charges. Additionally they carried, during their anti-sub days, buckets of hand grenades to thwart the threat from below. On the night of the 5 June 1944 they also carried a lot of other equipment – some incredibly secret and priceless new communications apparatus, needed to secure the success of their mission. 

The boat was packed with explosives that were to be detonated should the Medusa and its equipment fail and fall into enemy hands.

Alan Watson, the captain of Medusa in 2019, says: “These men, most of whom were in their early 20s, very much viewed the mission as a one-way trip. They were the first ship to arrive at Omaha Beach and if they negotiated the minefields successfully they were sitting ducks for at least the next 36 hours. They unquestioningly obeyed their orders, which were carried out to the letter.”

Pioneering navigation technology

A week before D-Day, The Royal Navy laid ultrasonic beacons on the seabed in 10 locations at the edge of the minefield. These signals would be heard on the ASDIC (Sonar) set on board. Medusa also carried an innovation called Gee – the world’s first hyperbolic navigation system. To operate it effectively, three shore stations had to send a precisely timed pulse and the ship measured the time differences between them and allowed for a correct position to be accurately plotted. 

Given that Medusa could not deviate from her exact position for up to 36 hours, fighting against currents and tides, it was vital that each and every piece of technology worked accurately. Gee was known to the Germans and, not unexpectedly, was jammed. However, there was also a second positioning system aboard code named QM, which later became known as Decca Navigator. 

It was so new there were only 20 hand-built sets in existence at the time. To complement her IT equipment, Medusa also carried an active radar reflector; again a new piece of technology in a wooden box on the after-deck. This made sure Medusa was visible on the radar of the approaching fleet. All of this equipment had only been recently commissioned, making Medusa an early pioneer of navigation technology that is still in use today.

Alan Watson continues: “War is not a pretty thing, but it does play an important role in pioneering and accelerating the advancement of technology innovation. Medusa was only one of 20 ships in a D-Day armada of 6000 vessels that carried this new technology. The ‘kit’ was vital to the success of the mission but she was also the unwitting pioneer of much of today’s navigational innovations.” 

Indeed, today people rely heavily on GPS but few would know that 75 years ago, its forerunner was prototyped by a little ship, carrying a huge responsibility, just off the coast of Normandy.

HMS Medusa – a pioneer of navigation technology

Medusa’s crucial role in the D-Day mission

Under the command of temporary sub-lieutenant Maurice Liddiard, Royal Naval Volunteer Reserve, the Medusa and her crew successfully held her position. Arriving off Omaha Beach on the night before the invasion, she remained on-station as the navigational leader for the approach to channel four, allowing the minesweepers to cut through and disarm the lethal field of German mines. This would clear the path for the rest for the following fleet to make their approach. Had Medusa failed in her mission the landings would certainly have been considerably much more dangerous – if they had occurred at all. 

Several lessons can be drawn from her mission and its subsequent success:

1) Precision and attention to detail is a vital component of planning and execution.

Without a detailed plan Medusa could not have played such an important role in the action. The vital precision that meant the difference between success and failure was the result of meticulous planning. The difference of the boat being a few feet out of position could have been telling. 

2) Innovation, commitment and responsibility are a formidable combination.

Innovation was being pioneered on Medusa but without the commitment of its operators it would have been useless. The boat’s crew unflinchingly accepted their responsibility and their commitment saw the plan home.

3) New technology, without stress testing, will always be an unknown commodity.

The navigational equipment accurately put through its paces by the crew, under the most testing of conditions, ensured deployment for decades following the war.  Decca remained an important navigational tool until 1993.  

Winston Churchill once said: “Give us the tools and we will finish the job.”

HMS Medusa carried an impressive set of tools, but without the unbending will and determination of her captain and crew the plan would never have been executed.

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