SMS  ("His Majesty's Ship ") was a lead ship of the  of light cruisers in the German  (Imperial Navy). Her class included three other ships: , , and .  was built at the AG Weser shipyard in Bremen from 1910 to August 1912, when she was commissioned into the High Seas Fleet. The ship was armed with a main battery of twelve 10.5 cm SK L/45 guns and had a top speed of .  was used as a torpedo test ship after her commissioning until the outbreak of World War I in August 1914, when she was brought to active service and deployed to the Baltic.

In the Baltic,  fired the first shots of the war against the Russians on 2 August, when she shelled the port of Libau. She participated in a series of bombardments of Russian positions until late August. On the 26th, she participated in a sweep of the entrance to the Gulf of Finland; while steaming off the Estonian coast, she ran aground off the island of Odensholm and could not be freed. A pair of Russian cruisers appeared and seized the ship. Fifteen crew members were killed in the brief engagement. They recovered three intact German code books, one of which they passed to the British. The ability to decrypt German wireless signals provided the British with the ability to ambush German units on several occasions during the war, including the Battle of Jutland. The Russians partially scrapped  while she remained grounded before completely destroying the wreck.

Design

 was  long overall and had a beam of  and a draft of  forward. She displaced  normally and up to  at full load. Her propulsion system consisted of three sets of Bergmann steam turbines driving three screw propellers. They were designed to give , but reached  in service. These were powered by sixteen coal-fired Marine-type water-tube boilers, although they were later altered to use fuel oil that was sprayed on the coal to increase its burn rate. These gave the ship a top speed of .  carried  of coal, and an additional  of oil that gave her a range of approximately  at . She had a crew of 18 officers and 336 enlisted men.

The ship was armed with a main battery of twelve  SK L/45 guns in single pedestal mounts. Two were placed side by side forward on the forecastle, eight were located amidships, four on either side, and two were side by side aft. The guns had a maximum elevation of 30 degrees, which allowed them to engage targets out to . They were supplied with 1,800 rounds of ammunition, for 150 shells per gun. She was also equipped with a pair of  torpedo tubes with five torpedoes; the tubes were submerged in the hull on the broadside. She could also carry 120 mines. The ship was protected by a waterline armored belt that was  thick amidships. The conning tower had  thick sides, and the deck was covered with up to 60 mm thick armor plate.

Service history

 was ordered under the contract name " "; the order was awarded to the AG Weser shipyard in Bremen in December 1909. She was laid down in April 1910 and launched on 13 May 1911, and during the ceremony, she was christened by the mayor of her namesake city. After completing fitting-out work, she began a short period of builder's trials on 12 August 1912 before being commissioned into the High Seas Fleet eight days later, under the command of  (FK—Frigate Captain) Heinrich Rohardt. The ship conducted these initial tests without her forward funnel installed. After completing her initial sea trials,  was used as a torpedo test ship on 1 December, replacing the light cruiser  in that role. Later that year, she embarked on a cruise in the Baltic Sea with other vessels organized into a training squadron.

Another such cruise took place in early April 1913, and in June, she joined the fleet for its annual cruise to Norwegian waters. In August,  went on another fleet cruise into the central Atlantic, steaming as far south as Tenerife in the Canary Islands. During the cruise, she participated in experiments with wireless telegraphy. Following the fleet's return to home waters, the annual large-scale fleet maneuvers took place in the North Sea.  thereafter went to Danzig for an overhaul that lasted from mid-September to late October. She resumed torpedo test duties on 26 October, but again joined the fleet for exercises in the Kattegat later that year, after which she went on another training cruise in the Baltic in December. The year 1914 began with exercises with the training squadron. As Europe drifted toward war during the July Crisis,  was ordered to patrol the Bay of Kiel to help secure the port's defenses. During a patrol on 27 July, she encountered the French dreadnought battleships  and , which had taken the French President Raymond Poincaré on a visit to Russia.

World War I
Following the outbreak of World War I at the end of July, she was assigned to the Coastal Defense Division in the Baltic Sea, under the command of Rear Admiral Robert Mischke. An  (Offensive Force) was created with , , and the torpedo boats , , and  for operations against Russian forces in the area. The ships were sent to Neufahrwassar on 30 July.  fired the first shots of the war with Russia on 2 August when she shelled the Russian port of Libau while  laid a minefield outside what had been Russia's forward naval base. The Russians had in fact already left Libau, which was seized by the German Army. The minefield laid by  was poorly marked and hindered German operations more than Russian efforts. From 6 to 8 August,  patrolled off the southern entrance to the Gulf of Riga, to the north of Libau. She then joined the rest of the Coastal Defense Division, which was sent north to attack Russian positions in Finland that lasted from 9 to 15 August. During the attacks,  shelled the Ristna Lighthouse in Dagerort. She also attacked the Bengtskär Lighthouse and a signal station at Pistna.

On 17 August, , , and three torpedo boats, sortied to escort the minelayer , and the next day, they encountered a pair of powerful Russian armored cruisers,  and . The Russian commander, under the mistaken assumption that the German armored cruisers  and  were present, did not attack and both forces withdrew. After arriving in Danzig on 20 August, the  was reorganized as the  (Unit of the Detached Admiral). Prince Heinrich, the overall commander of the Baltic naval forces, replaced Mischke with  (Rear Admiral) Ehler Behring. The new commander immediately began planning to make a sortie toward Gotland to search for Russian vessels. Behring ordered the operation for 26 August to sweep for Russian reconnaissance forces in the entrance to the Gulf of Finland;  was also to bombard the signal station at Odensholm on the Estonian coast.

 got underway the previous day to arrive in the area at the prescribed time. She encountered heavy fog in the early hours of 26 August while steaming at a speed of , and at 01:13, she ran aground near the lighthouse at Odensholm. The ship's double bottom was badly damaged and she was unable to free herself. The crew attempted to lighten the ship by throwing equipment overboard, but the vessel remained hard aground. The torpedo boat V26 arrived at around 08:30 and attempted to pull her free but was unable to do so. She therefore began taking off part of s crew in preparation to abandon the wreck. Since the cruiser had gone ashore near the lighthouse, which was one of her targets for the planned bombardment, she destroyed it with gunfire in spite of her predicament.

While the evacuation was going on, the Russian cruisers  and  appeared at around 09:00, having been alerted to the situation by the signal station that  had been unable to destroy. On reaching the area, they opened fire on the stranded cruiser. The Germans destroyed the forward section of the ship, but could not complete her destruction before the Russians reached the ship. Fifteen crew members from  were killed in the attack, and the ship's captain and his adjutant remained aboard and were captured by the Russians; they remained in a Russian prisoner of war camp until March 1918, when they were able to escape and return to Germany. The German code books were also not destroyed; the Russians were able to recover three of the books along with the current encryption key. They passed one copy to the British Royal Navy via a pair of Russian couriers on 13 October. The Russian Navy partially scrapped the ship in situ and eventually destroyed the wreck.

The capture of the code books proved to provide a significant advantage for the Royal Navy. The Admiralty had recently created a deciphering department known as Room 40 to process intercepted German wireless signals. With the code books and cipher key, the British were able to track the movements of most German warships; this information could be passed on to the Admiral John Jellicoe, the commander of the Grand Fleet. This allowed the British to ambush parts of or the entire German fleet on several occasions, most successfully at the Battles of Dogger Bank in January 1915 and Jutland in May 1916.

Notes

Footnotes

Citations

References

Further reading
 

Magdeburg-class cruisers
Ships built in Bremen (state)
1911 ships
World War I cruisers of Germany
History of cryptography
World War I shipwrecks in the Baltic Sea
Maritime incidents in August 1914
Shipwrecks in the Gulf of Finland
독일 순양함 SMS 마그데부르크는 1910년에 진수하고, 1912년 12월 10일에 취역한 제1차 세계 대전 당시 독일 마그데부르크급 경순양함의 네임쉽이다. 1914년 8월 25일 러시아군의 발트해 진입을 저지할 목적으로 출동한 마그데부르크 호는 실수로 오덴스홀름 섬에 좌초했다. 이 단순해보이는 좌초 사건이 제1차 세계 대전 당시 영국과 독일 간 암호 해독을 둘러싼 첩보전에서 가장 중요한 사건이 되었다.

이 섬은 러시아군의 영역이었고, 마그데부르크호가 좌초한 것을 목격한 러시아군은 이 배를 접수했다. 그러나 러시아군은 마그데부르크 호보다 더 중요한 것을 확보했다. 바로 당시 독일 해군이 사용하던 암호화 및 해독을 위함 암호책(Code Book)이었다. 러시아군이 노획한 이 암호책은 곧바로 동맹국 영국에도 제공되었고 영국의 40호실은 온전하게 입수된 마그데부르크 호의 암호책으로 전쟁 기간 내내 독일의 암호를 해독할 수 있었다. 유명한 치머만 전보도 이 암호책 덕분에 가능했다.

이력과 제원

이력 
 건조사 : 브레멘의 AG 베젤
 기공 : 1910년
 진수 : 1911년 5월 13일
 취역 : 1912년 12월 10일
 운명 : 1914년 8월 26일, 핀란드만에서 좌초 후 침몰.

제원 
 만재배수량 : 4,550톤
 길이 : 136m
 너비: 13.3m
 흘수선 : 5.1 m
 속도 : 최대 속도 27.6 knots
 항속거리 : 5,000 nm
 승무원 : 장교 및 사병 약 373명
 무장 : 105mm 함포 12문, 500밀리 함포 2문, 어뢰발사관 1개 및 기뢰 120발

마그데부르크 호의 출동과 좌초 
1914년 8월 25일, 독일 해군의 베링 소장은 순양함 아우그스부르크 호와 마그데부르크 호, 그리고 어뢰정 2척을 거느리고 핀란드만 입구에 정박하고 있었다. 베링 소장은 이곳에서 러시아의 장갑순양함대를 격파할 계획이었다.

17시 정각, 두 순양함은 1해리의 거리를 두고 천천히 러시아쪽으로 향했다. 기함은 아우구스부르크 호였다. 그러나 두 배는 안개가 짙어서 서로의 위치를 정확히 알지 못했다. 1해리의 간격도 그럴 것이라고 믿는 수준이었다.

23시 4분, 아우구스부르크 호에서 마그데부르크 호로 러시아군이 부설한 기뢰밭이 위험하니 남동쪽으로 방향을 돌리라는 전문이 날라왔다. 23시 7분, 두 순양함은 시속 15노트로 선수를 돌려 남동쪽으로 향했다. 마그데부르크 호는 오덴스홀름 섬으로 향하고 있었다. 만일 기뢰밭이 조성되었고, 러시아 함대가 존재한다면 곧장 동쪽을 향해 상트페테르부르크로 향할 계획이었다. 그러나 이때 마그데부르크 호는 오덴스홀름 섬과 배 사이 거리를 잘못 계산하고 있었다. 그들이 알고 있던 것보다 1해리(약 1.8km) 정도 더 오덴스홀름 섬에 가까이 있었던 것이다. 기함 아우구스부르크 호는 이미 동쪽으로 다시 방향을 바꾼 후였다.

8월 26일 0시 27분, 항로 변경 명령이 전문으로 도착했다. 암호 해독까지 4분이 걸렸고, 마그데부르크 호의 하베니히트 함장은 좌현 15도로 방향을 돌릴 것을 명령했지만, 그 순간 마그데부르크 호는 오덴스홀름 섬에 좌초해버리고 말았다. 당황한 함장은 좌초한 배를 다시 돌리고자 여러 가지 노력을 기울였으나 배는 움직일 생각을 하지 않았다. 날이 밝자 배는 오덴스홀름 섬으로부터 300m 거리에서 발트 해의 암초에 좌초된 것임을 알았다. 배는 여전히 움직일 생각을 하지 않는 동안, 러시아군이 다가왔다.

새벽에 오덴스홀름 섬의 러시아군 수비대는 마그데부르크 호가 좌초한 사실을 알았다. 수비대는 러시아 해군 정찰국장인 네페닌 대령에게 보고를 했고, 이때부터 분주하게 러시아군이 움직이기 시작했다. 하베니히트 함장은 점점 더 초조해졌고, 모든 기밀서류의 파기를 지시했다. 온갖 종류의 문서들이 기관실에서 화로에 던져졌다. 석탄을 주연료로 사용하던 배였다. 마그데부르크 호의 암호책은 모두 3권이었는데, 2권은 경황 중에 분실했다.

이윽고 러시아 해군 병사들이 마그데부르크 호에 승선했다. 독일 수병들은 순순히 항복했다. 함장도 체포되었다. 러시아는 피 한 방울 흘리지 않고 독일의 순양함을 나포한 것이었다.

마그데부르크 호와 40호실, 암호책 
그러나 마그데부르크 호 사건은 지금부터가 시작이었다. 러시아군은 수 개월 동안 이 배를 조사했다. 미처 파기되지 않은 문서들을 조사했다. 하베니히트 함장이 소각하려 했으나 못했던 2권의 암호책 원본이 바닷 속에서 발견되었다. 납을 달아 가라앉혔던 것이다.

러시아는 이 사실을 11일 뒤인 9월 초에 영국에 이 사실을 통보했다. 런던 주재 러시아 대사관의 해군 무관이 당시 해군성 장관 윈스턴 처칠을 방문하여 독일제국 해군 암호책을 발견했고, 그 암호책으로 비밀전문도 몇 건 해독했다면서 암호책을 영국에 제공하겠다고 했다. 러시아는 약속대로 10월에 암호책을 런던으로 이송해왔고, 처칠은 이를 즉시 해군 소속 암호해독반인 일명 40호실로 넘겼다.

이미 40호실은 1914년 8월 초에 전쟁이 선포된 줄 모르던 독일 무역선 한 척을 오스트레일리아 앞바다에서 나포하여 <독일 무역통신서>를 압수한 뒤였고, 마그데부르크 호의 암호책을 러시아로부터 받은 후인 11월 30일에도 한 영국 원양어선으로부터 독일 구축함이 침몰하기전에 바다에 던진 암호책을 가져다주었다. 영국은 이 암호책들을 이용하여 독일의 암호해독을 모두 해독할 수 있었다. 가장 유명한 것은 짐머만 전보이다.

그러나 독일은 마그데부르크 호에서 암호책이 탈취되었으리라고는 꿈에도 생각하지 못했고, 전후에 처칠의 회고록이 출간되고 나서야 이 사실을 알았다. 독일 해군이 일찌감치 에니그마에 관심을 기울이며 암호체계를 일신한 것도 이로인한 충격때문이었다.

더 읽어보기 
 40호실
 치머만 전보
 에니그마

1914년
마그데부르크
암호학사
1914년 해양 사고
1911년 진수된 선박