In the second half of 1938, the commander in chief of the German Navy, Reidel, instructed his subordinates to study the possibility of fighting against Britain at sea according to his will.
From the end of 1938 to the beginning of 1939, he successively put forward two plans for naval construction to Hitler: one is to focus on submarines and armored ships in order to fight against British Shipping.
The other is to build a fleet with small scale but huge assault force that can fight the British navy and shipping.
As a result, Hitler adopted the second scheme.
It is clear that Germany, in view of Britain’s weakness of relying on maritime transportation, wants to destroy its shipping at the beginning of the war.
In April 1939, after Hitler announced the abolition of the naval agreement, Randall again proposed the establishment of an ocean fleet equipped with internal combustion engines, so that Germany could achieve the greatest results from its extremely unfavorable geographical position when fighting against the British navy.
Randall’s guiding ideology was to force the British naval fleet to disperse its forces in order to concentrate superior forces to break them one by one.
The final operational plan drawn up by the German Navy is to use fleet destroyers, submarines and aircraft to lay mines along the British coast.
The use of submarines and auxiliary cruisers disguised as merchant ships to disrupt British shipping in the sea far from Britain.
Battleships, cruisers and auxiliary cruisers conduct single ship operations or formation operations in the Atlantic Ocean.
Germany tried to force British merchant ships to form an escort transport team and escort it with combat ships, so that Germany can use a powerful combat fleet to attack the British escort transport team and its guard ships.
In mid August, Germany began to deploy submarines in the channel leading to the west of Britain and near the northeast coast of Britain.
On August 21, the Battlecruiser admiral Earl Spey was transferred to the South Atlantic and deployed along the eastern coast of South America.
On August 24, the Battlecruiser “Deutsche” was dispatched to the North Atlantic.
On August 31, Hitler issued the first directive, which clearly pointed out that the task of the German Navy was to focus on the economic war against Britain and prevent the enemy from entering the Baltic Sea.
For this purpose, it is up to the commander in chief of the navy to decide whether to block the Baltic sea passage with mines.
In order to complete this arduous task, shortly after the war, the German naval command headed by Reidel turned to agree with the proposition of submarine fleet commander dunnitz, taking submarines as the best force for anti blockade, and determined that the focus of naval construction was to build submarines.
The British army has also formulated corresponding operational plans: once the European war breaks out, the British navy must protect and consolidate its maritime traffic line in the Atlantic, block the German fleet and cut off Germany’s maritime links with foreign countries.
Britain judged that the main forces sent by Germany to the Atlantic were submarines and a small number of battleships.
Therefore, the general task of the British navy is to defend against the attack of German submarines in addition to protecting its maritime traffic lines and preventing German surface ships from invading from the North Sea.
Its anti submarine method is to search in the British sea area first, navigate the transport ships passing through the dangerous area, and then organize an escort transport team.
After the outbreak of the European war, the curtain of the Atlantic naval war began.
Shortly after the British announced the maritime blockade against Germany, the German u-30 submarine cruising in the Hebrides found the British passenger ship “Athena” sailing from Liverpool to Montreal, Canada in the evening of September 3, 1939.
At about 19:40, the u-30 submarine fired three torpedoes at the British passenger ship without warning, one of which hit the key.
This incident marked the official outbreak of the Atlantic naval battle.
After the outbreak of the Atlantic naval battle, the German Navy invested troops in the Atlantic sea area one by one to destroy the British maritime traffic line.
Submarines and aircraft mainly operate in the North Sea and North Atlantic, and large surface ships attack British transport ships in the South Atlantic between South America and Africa.
Due to the lack of strength, it was unable to compete with the British navy.
Therefore, the German Navy adopted the method of decentralized use of troops to carry out mobile assault on the British maritime traffic line in the vast Atlantic sea area.
At the beginning of the Atlantic naval battle, submarines were the main force of the German Navy to destroy the British communication line.
At first, only more than ten submarines sailed every day.
Due to the small number and the limitation of berthing conditions, the scope of single boat operations is mainly concentrated in the sea area between Gibraltar and the Hebrides in the North Sea and the eastern North Atlantic.
The attack focuses on the English channel, where the Atlantic ocean shipping line of the Allies meets, and the channel West of the bay of Biscay.
Single boats are often used to ambush on the channels close to British bases and ports and the traffic arteries of nearshore routes.
However, in order to avoid over stimulating Britain and France, Hitler ordered the German Navy to only attack merchant ships armed or escorted by warships.
The scope of activities was limited to the eastern Atlantic Ocean and did not violate the Pan American security zone declared by the United States in the western Atlantic.
After that, the German Navy lifted such restrictions on Britain and France and began extensive submarine warfare.
After Britain strengthened its offshore anti submarine measures, German submarines went hunting in the vast sea area.
From January to March 1940, there was no new progress in submarine operations of the German Navy.
On April 9, the German army landed in Norway, and the Navy expanded the submarine base to Stavanger and Trondheim.
After the surrender of France, German submarines entered the ports of Brest, Saint Nazaire, lorion, laparis and Bordeaux.
Due to the shortening of the distance of submarines entering the Atlantic Ocean, the increase in the number of activities at sea, and the convenience of command, German submarines gradually transferred to the North Strait and the middle of the Atlantic Ocean for boat group operations since July 1940, frequently attacking the British transport team.
From July to October 1940, it was known as the “golden age” of submarine warfare of the German Navy.
At the beginning of 1941, the British Navy received 50 destroyers supported by the United States, and the escort force increased.
Within 10 days in the first and middle of March, it successively sank five German submarines, including three ace submarines, in the sea areas of Iceland and the Hebrides.
Since then, the German Navy submarine withdrew westward and began to conduct search operations on the route across the North Atlantic.
In the first half of 1941, the number of German submarines operating in the Atlantic increased to an average of 25 per day, and Italian submarines also began to participate in operations, resulting in a continuous increase in the total tonnage lost by merchant ships of allies and neutral countries.
In April 1941, the United States extended the Pan American security zone from 60 degrees west longitude to 26 degrees west longitude, and was escorted by the United States Navy in September, which restricted German submarines.
June 22, GermanyAfter the invasion of the Soviet Union, German submarines began to attack the convoy of the allies to the northern ports of the Soviet Union.
After the Pearl Harbor Incident in December, German Navy submarines began single boat operations off the coast of North and Central America.
From September 1939 to December 1941, German submarines sank 4.
1 million tons of allied ships, accounting for 54% of the total loss of 7.
6 million tons of allied ships during this period, and Germany also lost more than 40 submarines.
In response to the offensive of the German Navy at the beginning of the war, the British Navy invested various forces to carry out anti blockade operations.
The main force of the British navy in blockade operations is large surface ships.
On the eve of the European war, the British naval forces have been equipped with sonar, which is enough to deal with the threat of submarines.
In order to prevent German naval ships from entering the Atlantic Ocean, the British Navy sent several battleships, cruisers and fleet destroyers to exercise direct vigilance on shipping routes between Britain and Canada and between Britain and the United States.
Frequently change the route of the transport fleet and send cruisers to patrol the sea area near the main traffic roads.
In early September 1939, the British Admiralty formed a special combat group, which was composed of battleships “Nelson” and “Rodney”, Battlecruiser “counterattack”, aircraft carrier “Royal Ark”, cruisers “dawn” and “Sheffield” and 10 fleet destroyers.
In addition, it also includes the ships of the North Sea Patrol, whose task is to prevent German ships from entering the Atlantic Ocean and directly cover the shipping between Britain and Norway.
To this end, the Ministry of the Navy also plans to use the main naval forces stationed in rosette and Scarpa bay to support the North Sea Patrol, dispatch some troops to patrol between the southern part of Norway and the borkney islands, and organize a fleet of ships to cover the ships transporting troops and equipment to France on the channel close to the Dover Strait.
In order to control the Western passage close to the entrance of the English Channel and the Irish Sea and cover the ships between British and French ports, a ship detachment called “Strait force” was established in Portland.
In addition, an independent combat group was sent to Gibraltar to prevent German Navy submarines from entering the Mediterranean.
Another measure of the British Army’s blockade operation is to deploy mine barriers to prevent submarines.
In addition, in order to strengthen the blockade against the German Navy, the British navy has used fast mine laying ships and destroyers to mine several times in the sea area controlled by Germany.
The effect of British mine laying was better, but it started late.
The first mine laying was not started until April 13, 1940.
When the German army launched an offensive in Western Europe, the British Navy relegated the issue of mine laying blockade to a secondary position.
In order to block and destroy the maritime traffic lines of Germany, Britain set up a special auxiliary cruising fleet to monitor the shipping to Germany, forcibly check the transport ships to and from German ports and intercept German ships.
Submarines were deployed near Iceland, at the exits of the Straits of helgolan and skagrak, and near the coast of Norway to attack German ships.
In June 1940, after the German army occupied the bases and ports in Norway and France, the British Navy began to deploy submarines in the sea area near the German army bases in Norway and Biscay Bay in order to prevent the German Navy’s surface ships and submarines from entering the Atlantic Ocean, and the airmen also began to lay mines on the channel of the German army’s new base.
At the beginning of the war, the aircraft carried by the British Navy aircraft carrier was equipped with ordinary bombs, which was not suitable for anti submarine.
Since the aircraft carrier “brave” was sunk by German submarine u-29 on September 17, 1939, Britain stopped using the aircraft carrier for anti submarine and handed over the anti submarine patrol task to the shore based aviation force.
However, due to the limitation of distance, shore based aviation patrols found few opportunities for German submarines.
It was not until January 1940 that several aircraft of the British Navy began to install radar and put into anti submarine warfare.
The British Navy developed the anti submarine bomb relatively late, and the aviation forces acted alone and rarely cooperated with surface ships.
Therefore, the anti submarine effect of the shore based aviation forces was not great.
It was only in the middle of 1940 that the u-64 submarine of the German Navy was sunk.
After the outbreak of the Soviet German war, the German air strikes on the British mainland were reduced, which enabled the UK to dispatch some air troops from the cover base to strengthen the air cover of the escort transport team, and send better ships to escort the transport team.
In September 1941, the United States undertook the task of escorting the rapid transit team in the western Atlantic.
After the Pearl Harbor incident on December 7, the United States directly participated in the war, and Britain and the United States jointly formulated a new escort plan.