A U-Boat Gallery:
Submarine Warfare in World War I


The Technology - Read on.    |    Minelaying    |    The Lusitania    |    Artists' Views    |    Birth of ASW    |   Links


Patriotic art of U-boat  on surface & German flag, by Claus Bergen
This patriotic illustration was done by German marine artist Claus Bergen early in the Great War. It reflects a glamorized view of submarining put forth by navy boosters as an alternative to surface warfare when the German battle fleet settled in to a routine of blockaded inactivity. Increasingly as the pattern of stalemate persisted, the more adventuresome and motivated officers in the German navy sought to transfer from the High Seas Fleet to the submarine corps. Click to enlarge artwork. Bergen himself accompanied the U-53 on a mission in 1917, returning with a portfolio of salt-breezed canvases that captured the war at sea like no other's.

While the German battle fleet did pose a threat to Britain's navy and commerce, and did tie down most of the Royal Navy's battleships, it was really little more than an annoyance to British blockaders because of the Kaiser's standing orders to stay safely at base except in exceptional circumstances. By contrast, when fully unleashed, the submarine fleet began sinking merchant vessels faster than they could be replaced, posing a direct threat to the Allied war effort by cutting the supply line from America. Facts and figures on the unrestricted submarine campaign are presented in our U-Boat Warfare article. For more artwork by Claus Bergen, click here.

For another Jutland depiction by Claus Bergen, click here -- this shows the old German battleship Pommern exchanging fire with British cruisers moments before she was torpedoed and blown to atoms. For contrasting views of submarine warfare by artists from the opposing sides, click here.


Introduction: The Technology

SMU-35, German submarine of 1915: rendering by John Batchelor

U-35, prototype of an improved hunter submarine, was last of the U31 class (Typ). She could make 16+ knots on the surface using diesel drive, and up to 10 knots submerged, using her electric batteries. When the batteries were depleted, the ship surfaced, whereupon the diesels were linked to the electric motors and they were spun in reverse, becoming electric generators to recharge the batteries. All subsequent German subs used this arrangement, even the fat merchant subs and mighty U cruisers sent to prowl off America's Atlantic coast late in the War. Meanwhile U-35 rolled up Germany's top record sinking merchant ships in the Mediterranean. The first World War II U-boats borrowed heavily from the the earlier model, with generally happy results. And why not? On a single voyage alone, in the Med under Leutnant de la Perrière, U-35 accounted for 54 Allied steamers: no wonder this skipper was counted Germany's leading U-boat ace of the Great War. In all, the sub sank 224 ships for a total of 540,000 tons of shipping destroyed.

U-35: World War I U-boat, section through CT and control room: rendering by John BatchelorSection of the U-35 reveals the Germans' secret. Allied sub designers made the round pressure hull the outside hull of their vessels, making for very poor handling on the surface (a cylindrical vessel with no keel has no "bite" holding it in the water). The Germans wrapped the cylindrical pressure hull in a sleek, destroyer-like outer hull which yielded better performance on the surface, where the sub spent most of its time. Ballast tanks, fuel, and supplies were all carried within the odd corners of this steel wrap. German subs maneuvered less well underwater than the cigar-shaped boats of their rivals, but Germany's U-boats dominated the deep in both world wars. Below specs: German U-boat service badge from the First World War, with the inevitable Hohenzollern crown atop a laurel wreath; these silver pins were distributed to all veterans of three patrols beginning in 1918. German Second World War U-boat insignia was almost identical, but with a Nazi eagle clutching a swastika instead of a crown at the top, and fashioned of brass.

U-boat renderings by John Batchelor; copyright © 1979 by Time-Life Books - The Seafarers.

Specifications for the U-35:

Dimensions: 212' x 20.5' x 11.7'. Displacement: 800 tons. Armament: (1) 4.1" deck gun, (4) 18" tt. Carried (6) torpedoes on a mission. Engines: 2-shaft 1,700 hp diesel; 2-shaft 1,100 hp electric motors. Speed on surface: 16.4 knots. Submerged speed: 9.7 knots. Range: 5,000 nautical miles. Crew: 14.

Metric specs:
Dimensions: 64.7m x 6.3m x 3.6m    Displacement: 800 tons. Armament: (1) 105 mm deck gun, (4) 45 cm tt. Carried (6) torpedoes on a mission. Engines: 2-shaft 1,268-kW diesel; 2-shaft 821-kW electric motors. Speed on surface: 30.4 km/hr. Submerged speed: 27.96 km/hr. Range: 9,260 kilometers. Crew: 14.

Red horizontal line


Kaiserliche Marine U-boat service badge, 1918
World War I submarine service badge, Kaiserliche Marine, 1918

SMU-9, German submarine of 1910

SMU-9 (Seine Majestäts Unterseeboot 9, or His Majesty's Submarine #9), one of the old kerosene-burners which gave the British a false sense of security at the War's start because they traveled under a tall column of oily exhaust when surfaced, and so were easily detected. Built in 1910, the 188-foot sub displaced 493 tons surface, 611 submerged, and packed four 45-cm torpedo tubes. At the start of the War, Germany had only 35 U-boats ready for sea and regarded submarines as a novelty without much strategic importance.

HMS ABOUKIR capsizing

On September 22, 1914, U-9 under the command of Otto Weddigen torpedoed and sank three elderly Bacchante-class cruisers off Holland, with a loss of 1,459 British lives; above, the Aboukir capsizes while HMS Cressy stops and lowers boats to pick up survivors, making herself a perfect target for the lurking sub. Capt. Drummond of Aboukir thought he had struck a mine.

SMS U-14

U-14 was originally commanded by Korvettenkapitän Walther Schweiger, who later became famous for torpedoing the Lusitania. The sub made two wartime patrols, sinking 2 Allied vessels, before meeting her nemesis. Gunfire from the armed trawler Oceanic II sent her to the bottom off Peterhead with the loss of one crewman on June 5, 1915. U-14's 27 remaining submariners became guests of His Britannic Majesty for the duration.

Torpedo room on a U-boat

Bow torpedo room in a U-boat. The two torpedo tubes lie beyond the breech-lock wheels, from which the 'fish' were launched by compressed air. German subs carried 6 to 12 450-mm (18-in) torpedoes, mounted a 45 mm deck gun, and had dual diesel and electric propulsion. Torpedo rooms took up one-third of the vessel's interior space; engines, one-half; the crew lived in whatever crawl space remained. Two similar tubes pointed out the submarine's stern. By war's end, relying on its bigger-is-better philosophy, the U.S. Navy was fielding subs with double this number of torpedo tubes.

Depth charges cutaway diagram

First blood: In September 1914, HMS Pathfinder was ambushed by a U-boat and sent to the bottom with 259 of her crew. The 2,940-ton Pathfinder was the first warship to be sunk by a U-boat. Ship sank in 4 minutes. Feats like this and the Live Bait Incident demonstrated the effectiveness of sub and torpedo, leading the Germans to emphasize that branch of the navy, and eventually to cherish impossibly high hopes for it. Painting by W.L. Wylie.


Submarine Minelayers

Type UC sub

SM UC-5, a small (168-ton) Type UC1 German vessel designed for minelaying, after surrendering to the British at Ramsgate under the terms of the 1918 Armistice. These ships carried no torpedo tubes, but rather six chutes for sowing their mines (below). The subs were designed to be taken apart and shipped to their destination by rail, then reassembled for service. Evidently this one was employed to mine the English Channel and harbor approaches. The later type UB subs carried torpedoes as well as mines, and sank their share of merchant shipping by this means. The French, British and Russians also developed minelaying subs. Click here to enlarge photo, or on the link for more about mines.

Cutaway view of mine-laying Type UB submarine
Cutaway of a Type UB coastal minelayer.   Enlarge diagram   Profile

Type UB submarine
Type UB1 minelayer on the surface.

Type UB submarine

Cartoon shark teeth and eyes decorate the bow of UB-16. The antique scrollwork of the pre-dreadnought age may have been passé by WWI, but cartoon decoration of aircraft and subs was already widespread by 1917. This foreshadowed the cartoon "nose art" of WWII Allied bombers and Flying Tigers P-40 fighter planes.


Bold Deeds of Blockade-Running

Merchant submarine DEUTSCHLAND, WWI

One of the most audacious events of WWI was the transatlantic voyaging of the German merchant submarine Deutschland. The 1,500-ton sub made two round trips to the U.S. to wipe the eye of the Royal Navy. Here she is seen on return to Bremen in 1916, in a painting by Willy Stöwer.  Cutaway view of sub courtesy of British Gazette

Merchant submarine DEUTSCHLAND at Baltimore, WWI

The merchant submarine Deutschland docked at Baltimore, July 1916. She returned to Bremen laden with supplies valued at over $1M from German businessmen in Baltimore. All seven "merchant subs" were converted to raider U-boat "cruisers" by late 1917. The Deutschland was armed using two 5.9"(150 mm)/40 calibre guns scrounged from the old battleship Zähringen.

U-53 visiting Newport, RI

Nearly as stunning as the Deutschland's exploits was the visit of the U-53, a new German vessel with its ballast tanks modified to accept extra diesel fuel. It surfaced one October afternoon in 1916 at Newport, R.I., where its commander paid his compliments to the USN Commandant and calmly picked up the local papers. A train of curious naval officers, journalists, and photographers accompanied him aboard the U-53 for a tour of the vessel's appointments; then, scrupulously observing the protocol for a belligerent visiting a neutral port, Capt. Hans Rose upped anchor and motored to the vicinity of the Nantucket Lightship. Hovering just in international waters, he began picking off the ships he had identified in the shipping news of the papers he had purchased in Newport: by day's end he had despatched seven. Though no lives were lost, the episode inspired helpless outrage in Americans and rage among the British -- rage largely directed at the Americans, whose destroyers picked up the lifeboats but failed to interfere with the sub's grisly operations.

Crew of UB-77 posed around the conning tower of their sub
The crew of the UB-77 pose on their boat's deck after a successful patrol. Enlarge


The Lusitania Disaster

German submarine U-20, 1915

In early May 1915, the U-20 neared the end of a patrol in the Irish Sea. It had been a lackluster deployment; she had sunk several small coastal freighters and a sailing ship in two weeks on station, but had encountered no shipping of strategic value. A number of the sub's torpedoes had been duds, and she had only three left; she had been forced to finish off many of her unimpressive kills by shelling them at the waterline. Now the sub's crew was getting ready for the long, cramped journey home, around the north of Scotland. All the morning of May 7, they were socked in by pea-soup fog. Around 1100, the sun burned off the mist and the sub's skipper, Kapitänleutnant Walther Schweiger, made a detailed sweep of the horizon as the ship set out for home, running at high speed on the surface. Around noon, far ahead and on a converging course, he sighted a large cloud of smoke. After diving he watched through his periscope as a forest of masts and funnels came up over the horizon, so many he at first thought it was two ships. It was the Cunard passenger liner Lusitania making her monthly eastbound crossing from New York to Liverpool.

RMS LUSITANIA just before the torpedo hit, May 1915

On the morning of May 7, 1915 the Lusitania arrived unescorted in the Irish Sea and fell victim to a single torpedo from U-20 off the SE coast of Ireland on the last day of a crossing from New York. There were taut nerves aboard as the liner -- largest ship upon the Atlantic at the time -- entered the war zone; she was blacked out, her boats swung out as a precaution. Capt. Will Turner had received three messages warning of submarine activity in his path. Proceeding at a leisurely 15 knots (half her top speed) the great liner steered a straight course despite Admiralty warnings to zigzag in the presence of submarines; Capt. Turner was intent on taking his bearings to fix his position. When he made his last turn to complete his four-point bearing, he obligingly presented a perfect target for a bow shot to the waiting sub. The torpedo struck just abaft the starboard bridge; its detonation was immediately followed by a massive internal explosion which sank the 31,000-ton liner in less than 20 minutes. The fatal blow is thought by Robert Ballard to be ignition of coal dust in a nearly-empty fuel bunker, blowing out the ship's bottom around Frames 230-245; others suspect a boiler or main steam pipe explosion. Picture History of the Lusitania

RMS LUSITANIA goes to the bottom, May 1915

Undoubtably the most infamous U-boat kill of WWI: the Lusitania in her death throes off Queenstown (Cobh), Ireland in a masterful painting by Ken Marschall. Inrushing seawater was trapped on the starboard side by the longitudinal bulkheads, giving the ship a heinous list that made it virtually impossible to launch boats successfully. 1,201 died in the catastrophe, including 126 Americans. The atrocity did not bring America immediately into war, but it and other sinkings of neutral vessels created ill-will toward Germany in the States. The Lusitania Incident and other evidences of German bad faith were important components in the decision to join the war on the Kaiser 2 years later (the proximate cause being the Zimmermann Telegram to Mexico). The paint scheme shown here is correct: the ship's funnels were painted all black and a buff/gold band was added below the white superstructure for her wartime crossings. Top painting shows the "Lucy" in her peacetime colours.


The War At Sea

Torpedo hitting a freighter

Shortly after the Dogger Bank battle (Jan. 1915), the Germans launched an all-out U-boat offensive with little regard for neutral shipping or lives. The results were alarming, with one outrage piled on top of another. As in conflicts since the War of 1812, freedom of the seas became a burning issue in the U.S. Teddy Roosevelt led the charge for war; pacifist Secretary of State William Jennings Bryan resigned over the issue. By midyear the Wilson administration was engaged in white-knuckle negotiations with Germany. After months of deadlock, the Kaiser backed down and promised to respect neutral rights. He kept his promise -- for just over one year.

Victims of a U-boat float on wreckage in a huge swell

Early in the War a gentlemanly pace prevailed, with most U-boat skippers scrupulously observing the Cruiser Rules. Many subs actually towed lifeboats full of survivors to within an easy pull of land. But after being tricked by British crews and Q-boats and, in many cases, sunk, submariners by 1916 tended to shoot first and ask questions later. This led to castaways drifting on hatch covers or other bits of wreckage, sometimes for weeks or -- in rare cases -- for more than a month before rescue, as happened to these crewmen, lost in the immensity of the sea.

Sailors scramble off sinking ship as propellers tilt to the sky

Prior to the Lusitania Affair, U-boat skippers often sank their captures by gunfire to save precious torpedoes, after allowing the crews to abandon ship. As the War ground on, unrestricted sub warfare became a hot political issue in Germany, holding out hope of strangling Britain's supply line and forcing an end to the slaughter on the Western Front. It was believed that England could be starved out in six months. Therefore, despite the danger of antagonizing the U.S., the Kaiser authorized the second unrestricted U-boat campaign in early 1917. His expanded underwater fleet responded with savagery. Surprise torpedo attacks on merchant ships became the norm. People are still escaping as this steamer upends (note man sliding down line from the stern.) As Germany's fortunes declined, the U-boat assault became ever more vicious, destroying troopships and even a well-marked Canadian hospital ship, the Llandovery Castle. The last named was torpedoed by the U-86 and sank on June 27, 1918, with the loss of 258 lives.

Sailors scramble off sinking ship as propellers tilt to the sky

In a lovely pastel watercolor by Willy Stöwer, a torpedoed transport settles in the water while her nemesis observes calmly from a short distance. Most of the passengers appear to be getting off all right. The overall effect is a whitewash of the harsh violence of submarine warfare, unlike the unforced realism of Claus Bergen's work.   Enlarge


Artists' Impressions of the Campaign

Sub stopping a cargo liner: Illustration by German artist Willy Stoewer

The noted German marine painter Willy Stöwer -- a favorite of the Kaiser's -- shows a propagandistically correct debarkation of passengers before the unlucky steamer is sunk. This is the Linda Black of Liverpool, an actual ship that vouched for its treatment at German hands. This careful approach was more typical in the early phase of the campaign, when this piece is dated. Concealed guns, wireless calls for aid, and other subterfuges by prey met with harsh reprisals as he War bumped into the second half of its third year. This illustration exhibits Stöwer's mastery of weather and water admirably.   Enlarge

Sub sinking a freighter: Illustration by British artist

A sinking depicted by Allied illustrator J.D. Whiting stresses the fire and destruction of a submarine attack. Evidently the victim is being finished with scuttling bombs.

Sub sinking a freighter: Illustration by German artist Willy Stoewer

Illustration on the same theme by noted German marine painter Willy Stöwer emphasizes the grace of ships and the sea. Violence and death are notably absent from this sentimental watercolor.

Destroyer capturing German sub: Illustration by J.D. Whiting

A destroyer comes alongside a U-boat to force a surrender; another painting by J.D. Whiting. Very few subs were forced into surrender this way; certainly none that could dive and maneuver. The incident shown in this painting may have been fictitious. The real U-66, prototype of a class of advanced predator subs, disappeared without trace during a North Sea patrol in 1917.

U-boat cruiser in action: Illustration by German artist Willy Stoewer

Another painting by Willy Stöwer shows s gigantic merchant sub converted to a "U-boat cruiser" in action against a distant enemy. Deck gun is an 8.2" model.

Duel of the submarines: Illustration by Claus Bergen

Another of Claus Bergen's infectious paintings chronicles the end of a game of underwater chicken played by his U-boat, U-53, and a British sub, the J-6. After firing his torpedoes and missing, the British skipper precipitously withdrew. The German crew jeered his periscope as he fled. Incident took place off the Shetlands in April 1917.


Birth of Anti-Submarine Warfare (ASW)

Submarine periscope raised

Often the only warning before a U-boat attack was the "feather" or foam track of a curious periscope, followed by the bubbling wake of a torpedo. This was also the only obvious reference antisubmarine vessels had for targeting their invisible foe. In the last year of the War, American researchers devised a crude underwater listening device, the hydrophone. By using triangulation between signal from 3 chasing vessels, their crews could determine a target area to dump their depth charges with high accuracy. This was the genesis of sonar.

Depth charge: Cutaway diagram

The Allies' answer: the depth charge. These weapons were developed under the orders of Adm. Jellicoe at the demand of his captains in the North Atlantic for a sort of portable mine. Metal oil drums filled with 300 lbs of TNT (136 kg) detonated by a hydrostatic pistol, depth charges were developed as a desperation measure and first deployed widely at the end of 1916 -- a crude, inaccurate, but terrifying weapon. The hydrostatic pistol (2) is in the charge's axis to the left. Water entering a bellows chamber (1) forced the plunger down until it met the primer (3) at a preset depth. Kaboom! The weapon's effectiveness was enhanced by the deployment of a thrower or "Y" gun in 1918. In WWII a pattern of smaller charges could be thrown automatically from a device known as a Hedgehog.
Rendering by John Batchelor; copyright © 1979 by Time-Life Books - The Seafarers.

Depth charges in rack

Depth charges in racks on ELCO sub chasers at Harwich, 1918. Refined and manufactured in truly overwhelming quantities in the U.S., "ash cans" were the main weapon to force a submarine to surface in WWI. Improved by combination with automated delivery equipment, they proved one leg of an effective anti-submarine arsenal in WWII.

Destroyer TEMPEST dropping depth charges

HMS Tempest drops depth charges on a U-boat in 1917. Though actual hits were rare, a near miss could crack the sub's pressure hull or cause other fatal damage. Lethal within 25 feet, a depth charge could cause serious damage at up to 50 feet.

Destroyer HMS DEFENDER

Originally developed to screen the battleship fleet from torpedo attack, the swift destroyer became the principal antisubmarine weapon. Defender was a smallish British destroyer, built in 1908, 242 feet long, displacing 720 tons. She was armed with three 4" guns and seven torpedo tubes. As the war developed and the submarine threat became one of the destroyers' principal duties, swarms of larger and more robust vessels were built and deployed.

USS ROPER, WWI destroyer, silhouette

The American approach to destroyer design is profiled clearly in this Wickes class four-piper. Seen here at a naval review (the smoke is from salutes being fired), USS Roper was a 314-foot/96 m, flush-decked warship armed with four 4" guns (102 mm), a heavy torpedo armament of twelve 21" tubes (six tubes on each broadside, in two 3-tube swiveling mounts), and two depth charge racks. The 111 Wickes class vessels, built in 1917, each weighed in at 1,090 tons standard and could develop a top speed of 35 kts. Model   Schematic Rebuilt in 1930, but mothballed for much of that decade, Roper survived to have a distinguished career in the Second World War. She sank the U-85 off North Carolina in May 1942, served as a fast transport in the Med, and survived a kamikaze hit off the Ryukyus in May 1945, earning four battle stars. A four-piper traveling at speed

Aerial view of Atlantic convoy, 1917

Here was the true solution to the submarine campaign in two hard-fought wars: the convoy system. In 1917 when America came into the War, the Allies were losing the war on merchant shipping. After fumbling efforts to counter the U-boats piecemeal, the Admiralty adopted the road-map to victory devised by Adm. Sir John Jellicoe with the active assistance of U.S. Adm. William S. Sims. Now promoted to First Sea Lord -- the uniformed chief of the Admiralty -- Jellicoe got his priorities right and set out to staunch the hemorrhage without delay. The key to his strategy was a universal, mandatory convoy system.

The system emptied the seas of solitary steamers: easy prey for undersea marauders. Shown here, an entire convoy changes course in unison, zigzagging its way across the Atlantic. 1917 closed on increasing abundance of escort craft, shipbuilding overtaking the rate of losses, and the acknowledgment of ASW as top priority set by the Allied naval command. After an alarming Spring Offensive, the German war effort weakened as 1918 progressed until it finally buckled in October. And the U-boats were finally beaten in the last year of the War. After submarine raids became virtual suicide missions -- as the defeat of the Fatherland loomed -- morale in the U-boat fleet plummeted. At the same time, morale in the Allied service strengthened. To merchant seamen, an ancillary benefit of the convoy system was improved probability of prompt rescue when torpedoed. Sadly, being sunk became an occupational hazard, with some mariners chalking up three or even four of these devastating episodes.

Political cartoon urging Americans to fight 'the Hun'

Americans were overwhelmed with propaganda against the bloodthirsty Hun even before Wilson asked Congress to declare war (April 1917). Germanophobia surged across the land: German assets were siezed; German language books and sheet music were burned; study of German was banned in high schools.


Birth of the Sub Chaser
Purpose Built ASW Vessel

British sub chaser at sea

A new form of antisubmarine vessel was the sub chaser -- fast, wooden-hulled, gasoline-powered craft for coastal convoy work, mounting machine guns and depth charges. The predominant type in the first phase of the War was the 80-foot (24½ m) ELCO, manufactured in New Jersey for Britain. Here is one of the ELCO boats operated by the Royal Navy, skimming along at speed. With their plywood planing hulls, the ships were plenty fast, but not known for their genteel ride.

Sub chasers under construction in New York

Even before the April 1917 declaration of war, the United States marshaled its immense industrial capacity on behalf of the Allies; and after war was declared, the country was whipped into a patriotic frenzy of production in an all-out push for victory.

Sub chasers at the Otranto Barrage, 1918When there was insufficient steel for all-out production, the U.S. built ships of concrete and -- wood. Lots of them. When the U.S. Navy developed a beefier sub chaser, the 110-foot (33½ m) Standard SC, it was built of wood in multitudes of small private yards. The Standard SC featured a midships cabin behind the bridgehouse, and was powered by three 220-hp Standard Motor Co. gasoline engines, giving them a speed of 19 kts. The standard armament was one 3" (76 mm) gun for'ard, two 30mm machine guns on the bridge, and a Y gun and two depth charge racks aft. Sub chasers were used as escorts close to shore and on special antisubmarine warfare assignments. Above are two of the 440 SCs made, under construction in New York City. Note the large German liner in the background -- undoubtedly being converted to a troopship.

At right, a sub chaser on patrol: the U.S. SSC boat IX4 (SC-224) romping through the waters where the Ionic meets the Adriatic. Constructed of unseasoned 1-5/8" (41.4 mm) longleaf pine planks at a yacht builder's on Lake Erie, the 50-ton chaser had an unusual story. After crossing with her mates in a convoy from Bermuda, one of IX4's engines blew on the last leg into Malta. In the Royal Dockyard, her Chief dismounted the blown engine and hoisted it ashore, and then moved the center engine into its place. A spare, larger set of propellers came from the mother ship's stores and the center screw was removed; enthusiastic help came from the dockyard geeks. When the crew trialed the boat, they found she was just as fast as before and with 50% increased range, making her the utility boat for operations requiring special endurance. Along with several squadrons of American boats, the 224 boat was assigned to the Otranto Barrage deployed between Italy and Greece. Sub chasers specialized in killing returning submarines which had little or no sting left and whose crews might be fatigued and sloppy at the end of a mission. Chasers worked in teams of three boats, determining a sub's location by triangulating its audio signature as heard from their three different sets of hydrophones. The chasers would then depth-charge the indicated area intensely. This method racked up an impressive record of kills compared to the undirected depth-charging routines followed earlier in the War. The sub chasers' exploits in the Second Battle of Durazzo (Oct. 2, 1918) were recorded in Milholland's 1936 book The Splinter Fleet of the Otranto Barrage. The invention of hydrophones became the basis for the development of sonar, a key component of ASW since WWII.

U.S. WWI sub chaser SC-131 underway
Sub chaser SC-131 at sea.


Backing Up the Undersea War

SMS VULKAN

Germany too marshaled its technological genius to support the submarine campaign. Here is the SMS Vulkan of 1908, sub tender and salvage vessel (Hebeschiff) for the Baltic U-boat fleet. In effect she was a mobile floating drydock, capable of lifting a U-boat from the sea floor into her belly, or servicing a full-size U-boat and a smaller one at the same time. Each of her cranes (visible just forward of the truss structure amidships) could lift 500 tons at the rate of 30 m/hour. A Type IV U-boat is exiting the tender's bow aperture in this vigorous illustration by Alex Kircher.  Model of the Vulkan  *   Scroll to bottom of model review for a gallery of photos of the ship.

Sub departing tender SMS VULKAN

A U-boat floats out of the tender after repairs. A similar but slightly larger vessel, the Cyclops, serviced the North Sea U-boat flotilla. Their 12-knot cruising speed allowed the tenders to remain in easy distance of their sub flotillas when all were deployed. Both sub tenders were surrendered to Britain at war's end, but Vulkan sank under tow to Britain in spring 1919.

Concrete sub berths in Belgium

The principal German submarine bases were on the English Channel coast of occupied Belgium at Ostend, Bruges, and Zeebrugge (Ostend and Zeebrugge being the two outlets of the Bruges Canal). Here are the Zeebrugge "sub pens" -- berths for the U-boats within a hardened concrete structure. This hard shell, up to 16 feet thick, protected boats and crews from bombardment by British monitors or aircraft.

In April 1918, the Zeebrugge base was the target of a British commando raid that blocked the channel and disabled its pens temporarily. The raid was greeted ecstatically in Britain, as a decisive blow against Germany's submarine force. Medals were awarded and heroes paraded. However, U-boats from Ostend and Bruges were still able to put to sea afterwards.

Torpedo room on a U-boat

Late in the Great War, the giant merchant submarines were outfitted as frank killers, each armed with two 8.2" guns. Their exploits were facilitated by their great range; they also served as forerunners to the "milch cows" of WWII, fueling smaller U-boats at sea far from home. For a brief time in 1917-18, they wreaked havoc on coastal shipping off the U.S. Eastern Seaboard, until effective coastal convoys were instituted. Above, U-155 surrenders at Ramgate. Enlarge


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