Operation Neptune was the cross-Channel crossing phase of Operation Overlord. Operation Neptune placed all naval issues under the command of Admiral Bertram Ramsey whose command skill had already been seen in 1940 with the part he played in the evacuation of troops from Dunkirk.
Admiral Ramsey - second from the left, back row
Ramsey knew that such a vast assault would place a huge strain on the Royal Navy simply in terms of the number of boats/ships required. The administrative and organisational issues were also vast.
About 6,000 ships of all sizes were required for Neptune. This vast number alone posed major problems:
Ø Where would so many ships be berthed? If they were concentrated in the south alone they could be open to a German bombing raid.
Ø What mechanisms had to be put in to place for ships that broke down? How would they be replaced in terms of the task they had to carry out?
Ø How quickly could turn around be achieved for each journey – loading up in port in England and depositing in Normandy?
Ø What measures could be taken against a U-boat attack?
Ramsey’s plan was relatively simple on paper. It was assumed that the vast aerial power of the Allies would ensure that the fleet would be free from a German attack from the air. Therefore, the whole armada would be spear headed by a flotilla of 287 mine sweepers that would clear the way for the ships behind them. Behind them would be 138 warships that would bombard the German beach defences in Normandy itself. The troop carrying convoy would then sail from southern English ports protected by an escort of frigates and corvettes. Over 4,000 landing craft had been assembled and these were in need of protection.
Ramsey also had to organise the movement of 146 pieces of the Mulberry Harbour across the Channel by using a large number of tugs. This structure was of such great importance to the Allies, that no mistake could be made – and Ramsey had a very specific timetable to keep to.
Ships in 'Neptune':
Minesweepers: these were usually of the Bangor class. Of the 287 minesweepers used in Neptune, many were Bangor class. These ships weighed 672 tons and had a crew of 60. Their maximum speed was 16 knots and they were armed with one 40-mm gun, one 3-inch gun and four .303-inch machine guns.
Liberty ships were also used. These were 10,000 ton freighters which could be built in less than five days. These were produced in vast numbers and their use in the landing at Normandy – and after – was vital.
Armed salvage tugs were used primarily to move the Mulberry Harbour and to pull many of the landing craft. Nearly 50% of all landing craft were not capable of crossing the Channel under their own steam. The tugs provided this. They weighed on average 700 tons and had a crew of 30. They had a top speed of 13 knots. They were armed with one 3-inch gun, two 20-mm guns and two .303-inch machine guns.
Armed trawlers were of great value to the Neptune team. They acted as convoy escorts, shepherding and marshalling the transport ships. Hundreds were used in the D-Day landings. The ones that were armed with depth charges, also had an anti-submarine role as well.
RAF Air/Sea rescue launch boats were involved in Neptune to rescue those in need. With a top speed of 38 knots, they were capable of quickly getting to ships in distress.