100 years ago, on February 1st, 1917, Germany reintroduced unrestricted submarine warfare,
where any ship within the maritime war zones from any nation,
could, and would be sunk without warning.
This caused a crisis in Britain and France,
for how does one defend against a plague of U-boats? That's what we'll talk about, today.
♪ 'The Great War' theme ♪
I'm Indy Niedell. Welcome to a Great War special episode about defense versus submarines in the First World War.
When the war broke out, the military capabilities of submarines were unknown.
The British believed they would only be effective for coastal defense,
but the Germans would—literally—blow this theory out of the water on September 22nd, 1914,
when a single German sub sank three British cruisers.
The Allies realized they had some serious rethinking to do, to combat this new threat.
The initial measures taken met with mixed success,
and a merchant captain's choices when encountering a German sub were either to run or to try and ram it.
This brought about the "Q-Ship" Programme,
The "Q" stood for Queenstown, Ireland, their home port.
Now, these looked like regular merchant ships, and their purpose was to lure subs to the surface
where they would shell the merchant ship, instead of wasting torpedoes,
but the Q-Ships were armed, and would open fire on the sub.
While they did sink a few subs, many of the Q-Ships were themselves lost,
and eventually, it was concluded that they didn't sink enough subs to justify the program.
You could see the British perception of U-Boat warfare through the Q-Ships.
The Baralong Incident happened in August 1915, when the Baralong sank a sub that was preparing to fire on a merchant ship.
A dozen or so German survivors swam towards the merchant ship,
but the Baralong opened fire and killed many of them in the water,
and then sent a boarding party to kill the rest that made it to the ship.
But the Q-Ships in general weren't as successful as other methods of defense—like mines, for example.
Indeed, the Royal Navy tried to block off the English Channel with steel nets and mines.
This also had limited success, and most of the German subs were still able to navigate their way to the Atlantic.
The British also tried attaching a submarine escort to smaller ships.
This also managed to sink a couple of German U-Boats in 1915.
But the real problem then was finding the submarines in the first place.
So, they turned to the skies for help.
The Felixstowe F.2 Flying Boat had a much clearer and wider view of the sea, and could travel more quickly than a surface ship.
It also had a huge fuselage, so it could float on the water.
It was equipped with two heavy bombs set with fuses which were timed to explode underwater.
Now, these bombs weren't large enough to destroy a sub,
but the idea was that they could damage it enough to cause it to surface,
and then the seaplane could send coordinates to a destroyer, to take care of it.
These entered regular service in 1917, but patrolling the North Sea was a tough job.
The weather was often terrible, and the sea itself murky, and many F.2's were lost,
though some downed crews managed to make it home, by using the plane as a boat with the propellers as the motors.
These planes were also used for intercepting Zeppelins, but since they could not fly as high as the airships,
they had to attack them while they were taking off.
This meant being tugged by a cruiser or destroyer, until the plane was within range of Germany itself,
since they did not have the range to fly the whole way from Britain.
The Germans responded to this with seaplanes of their own, such as the Hansa-Brandenburg W.12.
They would travel in groups, and would sit on the water, and lie in wait for the enemy, and then take off and ambush them.
There were even dog-fights between F.2s and W.12s, with both sides scoring victories,
though they weren't very elegant, since these planes were not especially manoeuvrable.
But the British needed more eyes in the sky to keep track of all the commercial and military traffic.
Smaller planes didn't have wireless systems, so the British built airships of their own.
The 'Balloonatics', as the crews were known, helped to enforce the British naval blockade
on shipping to Germany, using a series of Scout-class airships.
They were pretty slow, though they carried bombs, a machine gunner, a mechanic, maybe a rifleman,
and later models even had parachutes.
But they had open-air cockpits, which meant flying conditions were mostly miserable thanks to the cold and the noise.
They were, however, very useful, especially in spotting commercial traffic that might need protection
and putting the fear of surfacing into the U-Boat captains.
And the Royal Air Service was vital in tightening the noose on incoming supplies to Germany.
The British, had also been experimenting with depth charges since before the war.
These were launched into the water, and sunk to a specific depth,
whereupon the fuse would be triggered, and the charge would explode.
They didn't have to make a direct hit because the hydraulic shock alone
could cause serious damage to a sub, and even pop rivets.
The first U-Boat sunk by a depth charge was on March 22nd 1916,
when U-68 was sunk by HMS Farnborough.
All 38 sailors were killed.
In spite of their effectiveness, depth charges were not produced in large numbers until late in the war,
but by 1918, Anti-sub ships carried between 30 and 50 of them as opposed to just two in 1916.
The most effective measure against submarines turned out to be convoys.
Yep, just travelling in groups.
Convoys were first used early in the war,
during the transport of British dominion troops like the Australians,
and Japanese ships would perform that function for the whole war.
The first regular British convoy in the Atlantic and North Sea war-zone, was July 16th 1916,
for traffic between the Hook of Holland and Harich.
Over the next six months, only one straggler of the fleet was lost on what the Dutch called the "Beef Trip"
because of the amount of meat being transported.
When unrestricted submarine warfare was re-introduced,
the French wanted convoy escorts for coal ships.
The Norwegians also wanted them after losing some vessels, and informal convoys began in earnest.
The British War Cabinet wanted more regular convoys, but the Admiralty did not comply with this.
They claimed they did not have enough ships to protect all merchant traffic across the Atlantic,
but that was based on assuming each vessel would get its own, individual escort.
They also calculated there were 300 ships a day, crossing to Britain,
when the actual figure was more like 20.
They argued that large convoys would simply provide more, and larger targets for the Germans,
and there was, secretly, a resentment of the convoy idea
because it was defensive, at a time when there was a 'cult of offense' among the Admiralty and the British Army.
But in April 1917 alone,
860,334 tons of shipping was sunk by the Germans,
and the Admiralty had to re-think.
That could, obviously, not continue.
And the Germans had set a goal of 600,000 tons per month
as the number that would soon drive Britain out of the war.
The Admiralty agreed to convoy all Atlantic shipments,
and this was extremely effective.
By the time a U-boat launched its first torpedo,
the whole convoy knew where it was, and could counterattack in force.
By October, the number of ships in a convoy had risen to around 36.
Naval losses plummeted to a tiny fraction of what they had been a few months earlier.
The Germans could not handle this, and began to intensify their efforts on shipping in the Mediterranean.
But they would never again reach their target of 600,000 tons of shipping sunk in a month.
This also meant that they would —by their own calculations—
never be able to starve Britain out of the war.
And there was a serious downside to targeting all ships, including neutral merchant shipping.
That meant that neutral nations, such as the United States, with its vast resources and population,
would no longer be neutral nations, but would instead become enemies.
I'd like to thank Roy Kirkby and John Clarkson for their research on this episode.
If you'd like to know more about the development of the submarine prior to the War,
you can click right here for a special about that.
And like us on Facebook and follow us on Instagram
for more pictures of flying boats and airships and all kinds of other cool stuff. See you next time.