The Otranto Barrage

[TARA]

I was interested when reading about the exploits of Oberleutnant Karl Doenitz during 1918, that the allies had built a barrage of sturdy netting across the Adriatic Sea between the heel of Italy and Albania. Naval vessels patrolled the barrage. Doenitz, who was based at Pola, regularly took his Uboat under this barrage and attacked allied shipping in the Mediterranean Sea.

I knew that harbours and ports were often protected by barrages and booms but had not realised that much longer barrages were placed across open seas.

What other similar barrages were used during WWI? Was there one across the Strait of Gibralter?

[horatio2]

The "barrage of sturdy netting" was not a fixed installation but a line of Auxiliary Patrol net drifters, lying to their nets. Originally the drifters were positioned on a fixed line across the Adriatic but from April 1917 they were deployed on random lines so that submarines could not be certain where they might encounter the nets.

[centurion]

I was interested when reading about the exploits of Oberleutnant Karl Doenitz during 1918, that the allies had built a barrage of sturdy netting across the Adriatic Sea between the heel of Italy and Albania. Naval vessels patrolled the barrage. Doenitz, who was based at Pola, regularly took his Uboat under this barrage and attacked allied shipping in the Mediterranean Sea.

I knew that harbours and ports were often protected by barrages and booms but had not realised that much longer barrages were placed across open seas.

What other similar barrages were used during WWI? Was there one across the Strait of Gibralter?

Given that the Straits of Gibraltar has a fair current through it a fixed barrage might be problematic and the nominal neutrality of Tangier (although increasingly dominated by France) and the international waterway status of the Strait might have also given rise to some issues under international law. In both world wars it was heavily patrolled (in WW2 a great many U boats were sunk there). A barrage was not always nets and mines could be laid so as to form a barrage There was a Dover barrage and a Northern Barrage ( between Scotland and Norway) and at least 3 U boats were sunk by mines in these

[TARA]

Thanks for the comments and information. Were magnetic mines used during WWI or were they much later?

[centurion]

Thanks for the comments and information. Were magnetic mines used during WWI or were they much later?

A WW2 introduction although I think there were experiments in WW1

[centurion]

Over 70,000 mines were laid in the Northern Barrage the vast majority of American origin (about 15,000 were British) They were all moored contact mines. It was considered that the 'gap' would not be completely denied to U boats until 100,000 mines were in place but the war ended before this could be achieved. All in all over 190,000 mines from both sides are believed to have been laid in the North Sea. The total from all sides in all waters was probably in the order of 235,000. The overwhelming majority being moored contact mines although some harbours were defended by sea bed mines detonated via command wire by observers.

The credit (if that's the right word) for the invention of the modern naval mine is disputed but it probably goes to Jacob Nobel the father of Alfred Nobel (of dynamite and prize fame) who supplied the Russians with them (some were used in the Baltic during the Crimean War), however Samuel Colt (the revolver man) also claimed to have invented them. They were initially known as torpedoes and some were used by the Confederates in the ACW (hence the quote "Full steam ahead and damn the torpedoes"). Whistler (the American painter) was later implicated in the illegal sale of large numbers of captured Confederate mines to Chile but it is probable that the US Navy was complicit in this and it was an early version of the Ollie North Irangate scandal. Mines came in basically two types -moored mines with a contact detonator (as Nobel's were) or command wire fired as Colt's were

Modern torpedoes were originally known as dirigible torpedoes to distinguish them from the moored variety

[TARA]

190,000 mines in the North Sea in WWI. That was a lot of mines, I wonder how many years it took to clear them from International Waters after the war and who did the work?

[centurion]

190,000 mines in the North Sea in WWI. That was a lot of mines, I wonder how many years it took to clear them from International Waters after the war and who did the work?

AFAIK each country was responsible for clearing the mines that they had laid in the first place - after all they knew more or less where they were. I think the bulk had gone by the end of 1920 (only for many more to be laid 20 years later)

[joseph]

Hi,

The first problem was clearing the German mines, which was allocated to countries by area.

A large proportion of the Otranto Barrage was fixed, when this proved infective the Drifters put their nets down as and where.

Regards Charles

[centurion]

Hi,

The first problem was clearing the German mines, which was allocated to countries by area.

Yes German offensive mining, which the Germans had not always retained effective records of (not unlike Argentinian land mines!) but German defensive minefields were cleared by what was left of the Kriegsmarine. unless they were in waters no longer German

[joseph]

The Kriegsmarine (formed in the 1930s) did provide crews to assist the british clear mines after WW2, not to sure about WW1 though.

[centurion]

The Kriegsmarine (formed in the 1930s) did provide crews to assist the british clear mines after WW2, not to sure about WW1 though.

Whatever it was called there was still a German naval force post 1918 and it did do mine clearing

[joseph]

Do you have a reference as it would be interesting to read.

[centurion]

190,000 mines in the North Sea in WWI. That was a lot of mines, I wonder how many years it took to clear them from International Waters after the war and who did the work?

Work to clear the Northern Barrage started in spring 1919. of the more than 73,000 mines originally laid about 5,000 had exploded prematurely soon after having been laid and over 30,000 mines were already ‘gone’ by spring 1919, either having sunk, drifted away or exploded during winter storms, over 20,000 mines were swept by autumn and the following winter storms dealt with the rest. 70 mine sweepers were used with 10 support vessels. There were seven sweeping missions carried out in 1919 - Arnd Bernaerts and US Naval reports

The Versailles treaty permitted Germany to retain 38 minesweepers. The new Reichsmarine organised these into two flotillas based on the pre dreadnought battleships Preussen and Lothringen which were converted into depot ships and according to the terms of Versailles these were responsible for clearing German defensive minefields in German waters. Looking at various lists of ships in the Reichsmarine the number of minesweepers was reduced to 30 in 1922 by sale for scrap or to other navies and some others were converted for other duties - presumably by this point the need to sweep old minefields was over. Nevertheless the minesweepers appear to have been a useful way to ensure that as many as possible German naval officers got sea time and looking at the careers of various German U boat commanders of WW2 quite a number started their naval experience on the sweepers between the wars.

[Airshipped]

There are plenty of accounts of the Northern Barrage:

https://archive.org/details/northernbarragem00annapol

There are of course plenty of claims as to their effectiveness or the futility of the exercise, but modern research (e.g. see the u-boat.net website) attributes several u-boat losses to it. One problem is that many who disliked Bacon (and there were many reasons to dislike the eccentric chap) usually tried to discredit everything he had done, e.g. from the Dover Patrol etc. Some of this relates to scene-setting through which Keyes' costly Zeebrugge raid can be the subject of contrasting praise. It's a messy subject, with selective memories in different officers' memoirs. The North Sea Barrage remains a debatable topic.

The Otranto Barrage itself gave rise to an incident in which a VC was awarded for attempting to face down a raid by Admiral Horthy (yes, he of WWII fame/infamy), in which the Austro-Hungarian forces sunk quite a number of the blockade ships but at grave risk to some of the best ships in their fleet.

[centurion]

I think that trying to evaluate a barrage through the number of U boats sunk by it misses the point. It's a bit like barbed wire, which probably killed very few if any but was the cause of a great many being killed. It modifies behaviour and performance to the detriment of the attacker and the benefit of the defender. So if a U boat has to run the barrage in daylight on the surface there is a better chance of it being detected and attacked by a surface ship or an aircraft. If it has to exhaust its batteries working its way through slowly and submerged then it will have to spend more time later on the surface recharging them with similar consequences. If it has to go the long way round to avoid a barrage then it is using up fuel and can spend less time in its cruising ground and will have fewer opportunities to attack allied shipping and so on and so forth

[horatio2]

Post-war mine clearance was a huge task for the Royal Navy. The Mine Clearance Service (MCS) enlisted more than 2,600 men from shore to suipplement the thousands of serving RN ratings, of all branches, who volunteered for the MCS in 1919. Men also entered from the RNVR, the Motor Boat Section and the Newfoundland RNVR.

[joseph]

I do think the Dover Barrage worked, not by the Submarines sunk, but by the Allied ships that stayed afloat.

Was that a mine or net barrage?

Was the Germans not supervised in their work after the war, considering it was only an Armistice for some time.