On 6 June 1944, two naval task forces landed over 132,000 ground troops on the beaches of Normandy as part of Operation Neptune, the seaborne invasion of northern France which made D-Day possible.  

Operation Neptune was the naval component of Operation Overlord: the codename for the Allied invasion of north-west Europe to liberate Europe from German occupation. Nearly 7,000 vessels took part in the landings on the five Normandy beaches. 

HMS Belfast played a pivotal role in Operation Neptune and the opening bombardment of D-Day. Join IWM curator Nigel Steel on-board the ship to explore the story. 

The unsung naval operations that made D-Day possible

© IWM

Voice over: On the 6th of June, 1944 Allied Forces launched the largest combined air, sea and land operation in the history of warfare - D-Day. The Normandy Landings were one of the true turning points of the Second World War and marked the beginning of the long and costly campaign to liberate Europe from German occupation. In our new three-part series we'll uncover all the elements of D-Day with episodes exploring the fighting at Sea, in the air, and on land. This first episode will focus on the naval side that made D-Day possible - known as Operation Neptune. Why did the Allies select the Normandy beaches? How did Allied naval guns help turn the tide of the battle? And why did the Allies almost cancel D-Day altogether?

But before we answer those questions a word from our sponsor World of Warships. World of Warships is an online multiplayer naval warfare game and it's free to play. There are more than 600 historical ships to choose from 11 different nations including battleships, cruisers like HMS Belfast and submarines. Work with your team to win high-stake sea battles rendered in stunning detail. If you register through the link in the description using the code 'WARSHIPS' you'll even get an exclusive starter pack worth €25. Now on with the video.

Nigel Steel, IWM Curator: Undertaking a contested landing on a hostile shoreline is probably one of the most difficult operations that you undertake ever in warfare. If you go back to Gallipoli one of the lessons there is being able to concentrate your force in sufficient strength that not only can it capture the beach, it can then break out and so when planning the biggest amphibious operation of all fundamentally everything was based on that principle.

Voice over: The first problem for the Allies was choosing where to land. The shortest and simplest route into France was via the Pas de Calais but the Germans were expecting an attack there and the whole area was strongly defended. Cotentin and Britany were more appealing, but as peninsulas they could easily be sealed off by German forces. Normandy was the best option leading directly into the heartland of France, but before any landing places could be chosen the beaches had to be studied at close hand.

Nigel Steel: One of the key aspects was actually looking at the physical nature of the beach itself. They discovered at Dieppe in 1942 that if the tanks landed on the wrong kind of sand, the wrong kind of shingle, they would just sink and they couldn't operate at all it was just impossible terrain. And so they came up with this way of landing men secretly in the night, often from small canoes. They would row ashore, they would then take samples, analyse the beach, they would survey it and bring that intelligence back and that information gathered at great risk was vitally important to Ramsey and his planners as they worked out exactly where to put the troops ashore.

Voice over: A first draft of the D-Day plan was signed off at the Quebec conference in August 1943. It proposed landing the following May with three divisions by sea and another two by air. Then in January of 1944 American General Dwight D Eisenhower arrived in London to become Supreme Commander of the Allied Expeditionary Forces in Europe. His headquarters, known as SHAEF, was responsible for delivering D-Day. In command of the naval operations was Admiral Sir Bertram Ramsey. Having organized the British evacuation from Dunkirk and helped push through the Allied landings on Sicily he was more than up to the task, but Ramsey now faced a problem. Eisenhower and his principal Army Commander Sir Bernard Montgomery both agreed that the existing plan wasn't strong enough. They wanted to land five divisions with three more by air.

Nigel Steel: Throughout the war landing craft were short. There were many competing places that they wanted to use them. The Americans had operation already going on across the Pacific, there were landings in the Mediterranean, there was a plan for parallel landings in the south of France that the Americans were very keen on, all of this needed the same limited naval resources and although landing craft were being made they weren't being made fast enough. The outcome of all the discussions was that finally there was an agreement to postpone the landings in the south of France, this freed up enough landing craft to be added to those available they were finally able to concentrate sufficient naval resources to undertake it.

Voice over: With less than 5 months to go preparing for D-Day became a race against time. Luckily the Allied navies had already won the upper hand over the Kriegsmarine. The German U-boat threat in the Atlantic had been severely curtailed in the summer of 1943 by a combination of Allied intelligence, radar equipped aircraft and convoy escort groups. While the last remaining German surface ships were crippled by the Battle of North Cape and raids on their bases in Norway. That allowed millions of United States personnel and millions of tons of war material to arrive safely in Britain and build up in strength for the big event. 

But as the Allies were consolidating their forces, the Germans were also building up their defences under the guidance of Field Marshall Erwin Rommel - The Desert Fox. Field Marshal Rommel was appointed Inspector General of the fortifications at the end of 1943. He discovered they were very patchy and so it was only through his energy and his drive that the defences themselves began to build up in strength. Because Rommel as a veteran of the First World War saw it very much in terms of stopping the landing on the beach. The defences had to be factored in and became a crucial element in deciding when and where to land.

The airborne forces needed a full moon to give maximum visibility, while the naval forces needed to land at low tide so that any submerged beach obstacles would be visible and could be removed as quickly as possible. Such conditions only emerged for a few days each month and as such the date was set for the 5th of June 1944. But preparations were about to take a turn for the worse.

On the 27th of April American troops destined for Utah Beach were rehearsing their landings on Slapton Sands in Devon. But their exercise was compounded by tragedy. First a miscommunication resulted in some troops landing during the live naval bombardment. Then in the early hours of the next morning eight American LSTs were jumped by a group of German E-boats who appeared out of the dark, torpedoed and sank two LSTs and badly damaged a third.

It was a stark reminder of the inherent dangers of amphibious landings. Perhaps worse, it exacerbated the lack of Allied LSTs and risked alerting the Germans to the D-Day plan. But still, operations continued and by the 31st of May the first troops were embarking their ships for Normandy.

Nigel Steel: Everybody was getting ready, they were all moving into position coming down from the different ports and beginning to collect in the channel and yet one of those factors which was always a severe risk across the English Channel the weather blew up. By the very early hours of the 4th of June it was quite clear that the weather was going to be so bad it would jeopardize the whole thing. Eisenhower took the big decision to delay for 24 hours. In the very early hours of the 5th of June Eisenhower faced the same decision again. He knew that these dates were the only ones where the moon and the tide all came together and if he didn't go now it would be at least 2 weeks and probably four before all those conditions would come together again. And it's one of those great moments of jeopardy on the eve of D-Day, where we see all of these great issues at stake, where the man in charge takes the decision and says it's time to go.

Voice over: On the 5th of June 1944 the largest armada ever to leave British shores began to make its way to France. A multinational force of nearly 7,000 ships and nearly 200,000 naval personnel, the majority of which came from the Royal Navy. The Western Task Force under rear Admiral Alan Kirk was responsible for Utah and Omaha beaches, while the Eastern Task Force under Rear Admiral Sir Philip Vian took on Gold, Juno and Sword. Alongside them were the support forces B and L to follow up. Together they would funnel through a zone known as Piccadilly Circus, but before they moved towards the beaches the first ships into action on the 5th of June were specialized Allied minesweepers.

Nigel Steel: Admiral Ramsey in his orders took personal control of this minesweeping operation because it was so important. The first thing to do was to sweep two channels, 2 miles wide from the point where all the ships were going to collect down towards the beaches. When the ships collected and went down and headed down through the channels toward the beaches they were going to be headed by a second mine sweeping flotilla which would be making sure that no new mines had been laid in these swept channels since they'd been swept.

Voice over: Likewise, to protect against German E-boats the Allies had been sowing mines themselves in the mouths of German harbours, but they needn't have worried. Seeing the weather, German commanders cancelled air and sea patrols, believing no landings could possibly take place. Only when Allied paratroopers hit French soil in the early hours of the 6th of June did the Germans begin to react. Around 5:00 a.m. a group of German E-boats attacked the Eastern Task Force sinking the Norwegian destroyer Svenner, but it was the only loss inflicted by German shipping on the morning of D-Day.

Above the Allied armada scores of fighters roamed the sky, while further out, pickets of destroyers and RAF Coastal Command aircraft kept German U-boats at bay. The first part of the operation was an overwhelming success, but having made it across the channel it was now the turn of Allied warships to attack the German defences. Their task was to overcome the German shore batteries to allow naval operations to go on unhindered and to soften up the beach defences for the landing forces.

Nigel Steel: HMS Belfast was there alongside another cruiser HMS Diadem and they were the two most powerful naval ships engaging the guns around Juno. HMS Belfast is armed principally with twelve 6-inch guns. Although the naval gunfire was an integral part of the D-Day plan, naval guns themselves are not that well suited for engaging targets on land. The trajectory of naval guns is very flat whereas to hit a target on land you really need to go up and down in more of a howitzer trajectory shape. Nevertheless, the naval guns were very heavy and so they could bombard the targets and even if they didn't destroy them they could knock them out by concussing the gunners, kind of banging on the roof of each of the concrete casemates and putting the guns out of action that way. And that's exactly what happened with the guns of HMS Belfast.

On the 6th of June, Belfast was tasked with engaging the gun battery La Marefontaine and she fired for 2 hours from 05:27 till just before the troops landed at about 07:20 and throughout that time, although it didn't destroy the target, when the 7th Green Howards landed and eventually captured the battery at the end of the morning they were able to report it had been knocked out of action and 50 prisoners were taken simply through the force of Belfast's gunfire.

Voice over: On the whole the bombardment saw mixed success. Designed to coincide with Allied air attacks some emplacements were badly damaged, while others survived unscathed. Nonetheless as the bombardment lifted, it was the turn of Allied landing craft to go in. But before they could reach the shore the Allied troops, packed into small landing craft and battered by Channel waves, had to deal with overwhelming seasickness.

Nigel Steel: The weather in the channel that had caused so much problem didn't completely abate and the seas were still very rough. Packed into the landing craft, they were issued with sea sickness bags a bit like the ones you get today in modern aircraft. The men would throw up into the bag, tie the bag, pass it to the man next door who pass it away and then drop it over the side. And there's one oral history story from a man called Eric Ashcroft who remembered when this was happening someone shouted out and what he was saying is "don't throw the bag over cause my false teeth have fallen in the bag!". But for many of the men this added to the fear and the terrible conditions and so when they eventually arrived at the beach and the ramp went down, this incredibly frightening moment. So many of them were just pleased to go back on land and get off the damn sea.

Voice over: Generally the landings went well, although success varied not only between beaches but beach sectors themselves. Where the bombardment was effective, landings accurate, and the first wave of tanks able to offer supporting fire casualties were light. But where they didn't casualties were higher. In particular on the American Omaha Beach a failed bombardment and sunken tanks combined with difficult terrain to create very bloody fighting. Some 10,000 Allied casualties were suffered on D-Day, at around 13:00 in the afternoon seven of those casualties arrived on HMS Belfast.

Nigel Steel: HMS Belfast has a large sick bay where we're standing now and it's testament to the size of the ship that the sick bay had two surgeons and an anaesthetist and it's probably for that reason that early in the afternoon on D-Day casualties started to appear off HMS Belfast and were brought on board to come into sick bay. That in itself was a fairly precarious procedure. The crane operator Stan Finn who was on duty that day remembered the difficulty of lowering a big wooden crate down to the landing craft, loading on the casualty on their stretcher, and gently bringing it on board so they could come down here to the sick bay. It's a testament to another way in which HMS Belfast played a pivotal role in the D-Day operation.

Voice over: The major problem on D-Day itself was supply. The tide rose faster than usual due to strong winds and engineers, already on a strict timetable, struggled to remove the explosive rigged obstacles in time. Damaged landing craft and vehicles clogged the beaches as the space to disembark became narrower and narrower. These problems in unloading prevented the Allies from building up momentum. By the end of the first day many strategic objectives had not been secured and the beaches had not been linked up. But despite all the problems D-Day was still a huge success. By the end of the 6th of June some 156,000 Allied troops were ashore, an achievement built on the planning and preparation of the naval forces. 

But their work was not over, in the days after D-Day German resistance stiffened and the Allied ground forces became embroiled in a brutal slugging match to break out from the beachhead. German U-boats in western Brittany began to attack Allied shipping in the channel. Though they had some successes, they took heavy losses themselves from Allied ships and aircraft now adept at hunting them down. In the main the Allies were able to build their forces for a breakout.

Nigel Steel: One of the most difficult things in undertaking a contested landing on the shore is to keep pumping in the supplies and the resources you need to advance and break out. The Allies knew that they would not be able to capture a port. All the ports had been heavily fortified by the Germans, it was going to be impossible to capture one of those in the first instance. So the Allies thought about it and came up with a remarkable plan to actually take a couple of harbours with them. These two portable harbours, which became known as the Mulberry Harbours, and install those in order to allow the rapid disembarkation of vehicles supplies and men over the weeks following the landings themselves.

Voice over: The harbours were up and running within 10 days of D-Day. The ingenious design including an outer breakwater, pierheads and floating roadways allowed supplies from large ships to flow in. But the Mulberries were put to the test in a storm 3 days later. The American Mulbury was put out of action, but the breakwater stayed in place allowing American LSTs to land directly on the beach. Meanwhile, the British Mulberry was repaired using parts from the damaged American harbour and will continue to supply the Allies all the way until September of 1944. Meanwhile further inland, the fighting was difficult and costly. The Germans had terrain on their side, while the Allies had to rely on firepower.

Nigel Steel: The ship's guns, once they'd engaged on D-Day, for them their job wasn't over. They continued for the next 5 to 6 weeks off the Normandy coast and as long as the troops remained within range they kept firing in support of their operations. Belfast continued to fire for all of that time, came back to re-ammunition twice, but was there supporting the troops until they moved beyond. The naval gunfire was an integral part of the land operations in making sure that it was sufficiently powerful to break out from within the strictures of the beach head itself.

Voice over: Thanks in part to their overwhelming firepower and in part their ability to reinforce faster than the Germans, by the end of August 1944 the more than 2 million Allied troops now in France were finally able to break out from the German defensive lines. They encircled the German forces and raced towards the Rhine. It was the beginning of a new campaign to to liberate Western Europe.

Nigel Steel: Today we tend to take the success of D-Day for granted, but at the time nothing was certain. And the success of D-Day, the operation itself, the landing on the beach, and then the breakout into Normandy was all built on the success of Admiral Ramsey's meticulous planning. He made the naval operation the bedrock of Overlord itself and the breakout into Normandy.

D-Day video series

Watch the other YouTube videos in our D-Day series: 

  • German General Erwin Rommel superimposed onto an image of a P-47 Thunderbolt destroying a target in a large explosion.
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    D-Day in the air: How the Allies ruled the skies over Normandy

    The Allies were certain that the Normandy landings would be an era-defining moment. Join IWM curator Hattie Hearn to explore how the Allies planned for D-Day, how their air power enabled ground forces to break into France.  

    Find out more in: D-Day in the air: How the Allies ruled the skies over Normandy. 

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    D-Day on land: The Allied landings in Normandy

    The land assault on Nazi-occupied France would determine the success or failure of the entire D-Day campaign. Join IWM Curator Adrian Kerrison at IWM Duxford to explore the story of the land battle for Normandy. 

    Find out more in: D-Day on land: The Allied landings in Normandy. 

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