Submarine Corsair.doc

AUTHOR’S NOTE: This is the draft of an article originally prepared in 2009 for publication in Sea Classics, a naval history periodical. In keeping with the “popular” format of this publication, I did not footnote it or provide a bibliography. I can provide a brief bibliography if anyone is interested. SUBMARINE CORSAIR THE DESIGN AND CAREER OF THE CRUISER SUB SURCOUF Jim Bloom [email protected] (301) 460-3309 Shortly after the end of the First World War, the great powers toyed with the idea of the “submarine cruiser” --a large, albeit stealthy, underwater commerce raider. This was a radical departure from the customary undersea torpedo boat role. It would possess the long range needed to cruise distant waters, could approach a convoy undetected, surface and clobber it with a combination of large caliber guns and torpedoes. It was a noble concept, but by 1942, mechanical teething problems in several navies, vulnerability to air attack, diminished strategic justification, and high cost relative to damage inflicted led to its abandonment, with the possible exception of Japan. The most noteworthy and renowned exemplar of this short-lived sub class was the Surcouf. However, the Germans and British beat France to the punch with the design; but it was France that took it the furthest and had the most extensive combat experience. PIONEERING GERMAN EXPERIMENTS, 1916-1918 The concept originated with the German navy in late 1916, when three large U-cruisers, “Type 139”, designated under"Project 46", were built by Germaniawerft, Kiel based on the success of the earlier converted merchant submarines “Type U-151”, also known as the Deutschland Class, after the lead boat. The latter had been retro-fitted with two heavy deck guns and torpedo tubes, but had been originally planned as long range cargo carriers. As laid down, the Deutschlands were supposed to evade enemy surface blockades and acquire critical equipment or material from distant neutral nations—particularly the United States before April, 1917. They were not commerce-raiders per se but were adapted to that role. Unlike the U-151s, the Type 139s were designed from the outset for war service. They enjoyed a degree of success and managed to take the war to the enemy across expanses of ocean. These purpose-built U-boats were armed with two 5.9-inch deck guns and 24 torpedoes launched in four bow and two stern tubes, and had a cruising radius of around 12,000 miles which permitted worldwide service to the waters around their adversaries' outlying colonies. The guns were laid by a rangefinder on the aft section of the bridge. With its two 150 mm deck guns, and the precision rangefinder in an armored conning tower, it could fight surfaced as well as submerged. They carried a large enough complement to furnish captured vessels with prize crews. Maximum diving depth was increased by strengthening the pressure hull over the usual thickness utilized by the hunter-killer subs. The German 'cruiser submarines' were not intended to operate with friendly surface ships, but rather to use their high surface speed to independently pursue enemy vessels. Their large size gave them greater storage capacity for fuel and consumables, extending their range and operational endurance. Their heavy cannon were particularly important when confronting a Q-ship or 'mystery ship', the disguised U-boat-baiting ships posing as unarmed merchantmen. It was believed that the big gun armament would be more effective ship-killers than torpedoes, which were slow to re-load, while the guns could rapidly lob salvos capable of catching fast-moving surface vessels. The torpedoes could be brought to bear on slower moving surface units or ships crippled by gunfire. Furthermore, the artillery shells occupied less space than the torpedoes, allowing for a greater number of re-loads. Surface crewmen were already familiar with the handling of the deck guns so that it should require less training time to perfect the gun-laying drill. Three of these large U-139 class subs, (displacing 2,450 tons surfaced, 302 feet overall length, 30-foot beam) were eventually built, and the results for the class, combined with the converted Type-151 merchant subs, were heartening, but mixed. Encouraged by the success of the converted cargo sub U-151 in Chesapeake Bay and the adjacent American Atlantic coastal waters, another Deutschland boat, U-156, U-117 (a Type UE-II long-range minelayer sub), and the large Type 139 U-cruiser U-140 were dispatched on similar missions on the far side of the Atlantic. After the war, the Germans claimed that the U-139 had made a cruise lasting a month. However, the US Navy was now ready for them, and the hunting was not as good. U-156 was lost with all hands on the return voyage when she struck a mine off Bergen, Norway, on 25 September 1918. Another trio of long-range submarines, U-155, U-152, and U-cruiser U-139 were making their way across the Atlantic in November 1918 when the war ended. A few of the German U-cruisers also made long voyages south to the Azores and the African coast, where they operated generally unmolested against shipping operating in the area, though one, U-154, was torpedoed by the British submarine HMS E35 off the coast of Portugal in May 1918. Several drawbacks were noted during combat operations. The complex structure of the gun turrets, in particular the piercing of the pressure hull to accommodate the barbettes, had a detrimental effect on the sub's structural integrity. The complex shape of the gun emplacements also retarded the sub's underwater speed. It was not the potential of these German Imperial Navy boats that set the pattern for post-war navies to follow, however. The dazzling successes of the German surface raiders were the true models. These ships, like the Mowe and the Wolf took dozens of prizes while submarines on all sides took hundreds. But the subs had short legs. So, after 1919, the thinking was that you could take a large submarine with an extended cruising range, add a few large guns and some extra equipment, and thereby deploy an invincible cruiser submarine, a weapon system that greatly enhanced the surface raider's chief asset: stealth. BRITISH EFFORTS—THE X-1 The squandered promise of the German U-kreuzers as well as their surface raiders was not lost on Great Britain, which developed it's own submersible commerce-raider, the HMS-X1, designed in 1921-23, and commissioned in 1925. The idea had actually been germinating in England since 1915, (the M-class big-gun coastal monitor sub) but the German lessons from the Great War triggered the 1921 design. There had been a British precedent of sorts. The Royal Navy had briefly experimented with a big-gun submarine during the war. Originally conceived as coastal bombardment monitors, the British M Class's role changed during the design phase to an anti-shipping concept. It was considered that the torpedoes of that day were ineffective against moving warships beyond 1,000 yards, whereas battleship-derived artillery was expected to substantially increase this range. Thus, in 1916 the Admiralty decided to introduce a submarine armed with one 12-inch gun of the type carried by Formidable class battleships. As a result they were big vessels compared to the standard boats of that time, 296 feet long and weighing nearly 1,600 tons surfaced. They would rise to periscope depth, fire one round (the gun could not be reloaded while the boat was submerged) and dive out of harm’s way. Of the three M Class submarines built (M4 was launched in 1920 only to be sold for scrap), only M1 was completed before the end of the war, though she was never used in action because it was thought that if she was copied by the enemy Britain was likely to suffer more from the use of the 12-inch gun than Germany. Why this was never thought of before construction remains a mystery. M2 and M3 were completed in 1920. M2 was converted in 1925-1927 with a hangar and catapult installed forward of her conning tower to accommodate a small 2-seat floatplane for observation, a novel concept that only the Japanese were to use to any effect during the Second World War.   The mounting allowed them to elevate by 20 degrees, depress 5 degrees and train 15 degrees in either direction from the center line. The gun was fired while the vessel was at periscope depth, with only the muzzle above the water the sighting being done over a simple bead sight mounted on the barrel with the periscope acting as a rear sight .  M1 and M2 also had four 18-inch (450-mm) torpedo tubes whilst M3and M4 were designed with 21-inch (533 mm) diameter tubes and were 3 meters longer to accommodate them. At 2,820 tons displacement surfaced, 363.5 feet length and 30 feet beam, X.1 was the largest submarine extant in the 1920s. Constructed with a double hull, divided into 10 watertight compartments, the external tanks carried most of the fuel, only 9% of the diesel being carried inside the pressure hull. Designed to attack any armed merchant ship by gun action alone, it was decided a 5.2" caliber gun was required.   Two twin mounted guns were fitted in turrets fore and aft of the conning tower.   The concept of operations for the British boat was to surface suddenly in the middle of an enemy convoy and open fire to knock out any escorts before finishing off the transports. The broad beam and great size of the vessel made her a stable surface gun platform, keeping the guns well above the waves. The muzzle components of the open gun mounts were not watertight, requiring the gun crews to climb up to their positions after surfacing. An inflatable rubber seal between the hull and the rotating gun mounts proved surprisingly effective. The fire control tower carried an advanced 9-foot (2.7-meter) rangefinder. However, as noted, the guns could not be deployed while the sub was buttoned-up, requiring the handlers to come out on deck. X.1 was not a success. From the beginning of her career, she was a hard-luck vessel, dogged by mechanical breakdowns and accidents. The badly designed diesel engines proved nearly impossible to maintain. Gun-handling was cumbersome, requiring 56 of the crew dedicated to manning the guns. Sought after rate of fire of 6 per minute fell far short due to the slow operation of the hoists. The loading of torpedoes was particularly awkward on account of the cramped space allotted in order to accommodate the guns and their apparatus. Although X.1 handled well underwater, particularly after installation of a second set of bow planes, she spent much of her short service life dockside, under repair. In 1931, she was damaged in dry dock when carelessly installed supports collapsed and she fell over on her side. In the depths of the Great Depression, the admiralty decided X.1 was not worth repairing. She was finally scrapped in 1936. Oddly enough, the ultimate reason X.1 was scrapped, according to the Royal Navy's Director of the Tactical Division, was that a successful demonstration by Britain of the utility of the sub in destroying merchant shipping might inspire her enemies to produce similar subs and Britain, being highly dependent on seaborne imports, would thereby have the most to lose. It was said that her crew were extremely proud of their monster submarine, and brought her weapons systems (hydrophones, active multi-frequency Asdic, horizontal rangefinder mounted on a periscope, gunnery control tower, gunnery computer, two twin power-operated gun turrets with shell hoists, six 21inch bow torpedo tubes) all to a high degree of efficiency. As for the mechanical difficulties, informed opinion holds that they might have been fixed with a bit more of an investment, but since the Washington negotiations, X.1 had been left as an unwanted stepchild, shunned by submariners and cruiser specialists alike, instead of taking her place as the lead ship of a powerful new class of British Empire protection submarines to be based out of Singapore, deterring Japanese hegemonic plans.  Further review of the concept demonstrated that cruiser subs would be susceptible to ramming as frequently happened to British subs in WW I from operating in close conjunction with surface ships. The remaining 11 cruiser subs planned to accompany the X.1 were canceled and Britain wound down her submarine fleet and trained them to attack surface ships and escort vessels. FRANCE ENTERS THE FIELD—THE SURCOUF: CONCEPTION, DESIGN AND TEETHING TROUBLES Arguably, the most successful (relatively speaking) interwar U-cruiser design was France's Surcouf. although the vessel was never battle tested in the wartime role for which she was designed. The "croiseur sous-marin"  design was somewhat derivative of the 1916-18 German experiments and was seen as a means to circumvent the 1921 Washington Naval Arms Limitation Treaty's building limits on surface cruisers. Since submarines were not so restricted, it was thought to duplicate the cruiser's role in destroying merchant shipping outside the treaty by making the cruiser a submersible. France had originally intended to build six of these subs, but the 1931 London Naval Treaty came into force after the initial unit, Surcouf had been laid down, but before the sisters were begun. The planned flotilla would operate in two divisions of three subs, which were to surface among an enemy convoy in a triangular formation. The London treaty for the first time circumscribed the standard displacements and gun calibers of submarines. This effectively put an end to further sub cruiser construction by the signatory powers. In deference to her proposed role, she was named after the famous French privateer (i.e. government contract pirate) Robert Surcouf who ravaged British merchant shipping in the Indian Ocean during the Napoleonic Wars. This was emblematic of her intended function as an undersea corsair conducting a 'guerre de course'. During the First World War, France had effectively abandoned it's quest to become a preeminent naval power and concentrated on meeting the needs of the Army facing the Imperial German forces on land. The Navy was forced to cancel most of its planned major warships, and many vessels already in service were laid up and had their armament removed for land service. In a similar way to the British Admiralty, the French Navy saw the large submarine as a means of restoring France's naval position at a time of financial cutbacks and international disarmament initiatives. As part of her war reparations, France had obtained the German U-cruiser U-139, which she renamed Halbronn. The French Navy had been impressed with the German sub's armament, surface stability and armor protection, but failed to take note of its underwater unsteadiness and the unreliability of U-139's diesel engines, which never produced more than 50 percent of their nominal rated horsepower, corresponding with the British X-1's above noted similar troubles with its undependable engines. Laid down in 1927 under Project "Q5", built under the 1926 program, it appears that, unlike the German prototypes, the Surcouf was initially thought of as a shore-bombardment coastal monitor, more akin to the British M class. Although multi-gun designs with two twin and even triple turrets were proposed, at an earlier phase—Project 'J'--it was initially proposed to emulate the M-class by arming her with a single 12-inch gun as used in the pre-dreadnought battleships. Her ultimately chosen twin 203 mm (8-inch) turret guns were the largest caliber permitted under the terms of the Washington Treaty—otherwise she would have come under the definition of a 'capital ship'. No other navy anywhere built submarines of this size between the wars. Over 361-feet long and 4400-tons displacement when at a full load submerged, she carried an impressive armament of 12 torpedo tubes in addition to her two 8-inch naval guns. An interesting innovation, perhaps inspired by the British M2's experiment with accommodating a small float plane, was the incorporation of a water-tight hangar housing a specially designed Besson MB-411 two-seat monoplane with a single central float and stabilizing wing-tip floats. This plane was to be used both for target acquisition and reconnaissance. There was also a small motor launch of 16 feet length overall housed in a recessed watertight welldeck. This was to be used for boarding enemy merchant ships and taking off prisoners, for which a special holding cell was reserved aboard the submarine. Under the rules of war, civilian crews and any passengers were to be offloaded to a neutral port at the earliest convenience. She was powered with 2 Sulzer Diesels at 3,800 hp each (total 7600 hp) for surface running which could produce a top speed of 18 knots while surfaced. Submerged propulsion was provided by 2 electric engines each developing 1,700 hp for a total of 3400 hp, which gave a maximum speed of 8.5 knots dived. Her maximum operating range was 12,000 miles at 10 knots surfaced, or 7,800 miles at 13.5 knots, and her mission endurance was 90 days. At full strength her crew numbered 150 men. Here submerged range was 81 miles at 4.5 knots and 68 miles at 5 knots. Although “crush depth” was was 420 feet, maximum practical operating depth was 260 feet. Her 1929 launch was portentous. She was momentarily stuck on her downward course, wobbled as if to topple over, then eventually steadied and eventually continued down the cradle into the water.. Though there were clandestine military ceremonies attached to the launch, no photographs were permitted in keeping with the secrecy of the as yet unproven design. She would not be ready to enter service until 1934. During trials a number of drawbacks were observed. These largely revolved about the 8-inch turret configuration, her principle asset, but also entailed other aspects of the design—stability and reliability, for example. On hindsight these may have been corrected in follow-on production boats and then retro-fitted on the Surcouf, but, as mentioned, this was fated to be a one-off sub. I will mention some of the more nettlesome difficulties. To begin with, ballistically the guns had an ideal effective range much farther than the 15-foot wide rangefinder, located just forward of the conning tower, could “see”. These guns could, properly directed, destroy targets out to 24 miles. As it happened, the range of the turret guns was severely limited by the low height above water of the rangefinder—the designed maximum sight range of the rangefinder was 12,000 meters (7.45 miles). This could theoretically be extended out to 16,000 meters (9.93 miles) by spotting through the auxiliary periscope. Observers in the Bresson aircraft could, of course, spot targets at much greater ranges than the fire control apparatus, but the aforementioned negative impact of the turret traverse and elevation, nullified this advantage. Longer target distances would require the use of the aircraft for spotting, but since Surcouf carried no catapult there was no guarantee the aircraft could be used in all circumstances and sea states. Plus, lacking a catapult, the launch was cumbersome and time-consuming, necessitating the removal of the plane from the hangar , winching it back on rails, attachment of the wings an propeller (stored alongside within the tight tubular structure), setting the plane down in the water using a crane, then making a waterborne take-off. All this took at least a half hour. Using the rangefinder alone, in practice it was found impossible to spot fall of shot further out than 7,000 meters (just under 4 ½ miles). What's more, the rangefinder and fire control position proved to be sited too near the muzzle of the guns and was thus usually blinded by gunsmoke upon opening fire. The plane had a range of up to 450 miles with pilot alone or 250 with the observer aboard. While not specifically noted as one of its purposes, its conceivable that this large submarine with its extra space to accommodate captives and prize crews, could have been used for commando type missions. The French boat is almost identical in size to the USS Argonaut, the submarine used to carry 120 of Carlson’s Marine Raiders to hit Makin Island in 1942. The water-tight design of the turret involved a unwieldy raising of the entire turret once surfaced to enable it to clear the sealing collar and traverse. It was felt that the waterproofing and locking arrangement adversely affected accuracy. The muzzles were closed by hinged tompions worked by an endless screw, and the barrels pivoted in a ball mounting. The guns could on that account be loaded underwater with shell and bagged charge, but could not be trained until on the surface. Each gun had an ammunition stock of 150 rounds. Fire could be opened in three and a half minutes from the command to surface being put into effect when surfacing in calm weather. In rough weather this time could become almost five minutes. ., The rate of fire achieved was only four rounds per gun per minute, instead of the five intended. Due to the aforementioned arrangement for sealing the turrets during underwater transits, the 8-inch guns were reported to suffer from abnormal dispersion as to range, even though fire was controlled by a mechanical computer similar in operation to the British Admiralty's “Fire Control Clock.” Two surprising omissions were lack of any manual sighting arrangements on the mounting itself (which might have helped to overcome some of the aforementioned target acquisition problems), and the inability of the fire control apparatus to engage shore-based targets—which, along with seaborne commerce-raiding, surely should have been its principal raison d'etre. There was an onboard accommodation in an adapted cargo compartment for up to 60 prisoners—expected crew or passengers taken from captured or sunk merchantmen—and a 15-foot speedboat housed in a recessed water-tight compartment on the foredeck for transporting them from the surface vessels to the sub. The sub tended to roll excessively on the surface in any kind of ocean turbulence, attributable to the top-heaviness of the massive 180-ton eight-inch turret. Lacking large quick-blow tanks in her bows as had been deemed essential in the British X.1, surfacing and diving were sluggish—particularly in light of the looming airborne threat to submarine operations, which demanded rapid diving to elude attack by patrol aircraft, such as the German U-boats encountered to their chagrin, 1941-45. To an extent the two twin 37-mm anti-aircraft mountings atop the hangar structure, just aft of the conning tower, augmented by several 13.55-mm machine gun mounts, could fend off aerial attacks such as might be encountered in the early 1930s. But this firepower could not surmount the tardily submerging sub's vulnerability to the type of patrol planes and methods developed after 1941. Further, she was rather clumsy underwater, which could have been problematic in taking evasive maneuvers while under depth charge attack. Her surfaced rolling proclivity at times was observed to reach 40 degrees, causing some spillage of battery acid creating small fires and damage to wiring. The riveted hull required strengthening to bear the weight of the eight-inch turret without having the seams work open. The seemingly dangerous expedient of using submarines as convoy escorts—during which many highly imaginative stories of Surcouf torpedoing Allied ships grew up—made much more sense when one considers Surcouf's surface combat potential. During calm weather, her aircraft could patrol around the convoy. In theory her guns could out-range the 15-cm (5.9 inch) guns customarily carried by merchant raiders, and a larger surface unit would be vulnerable to submerged attack from her 12 torpedo tubes. While the above roster of drawbacks may seem to have doomed the design, modifications made during the shakedown cruises in the mid to late 1930s attempted to overcome these handicaps. Her prewar conditioning and career were far from painless, but on the outbreak of hostilities in September 1939 Surcouf was brought up to combat readiness. There follows some highlights of her work-up and fine-tuning prior to engaging in combat patrols and her record at war. SURCOUF'S EARLY CAREER AND WAR SERVICE ` The year 1931 was devoted to diving trials and the following year she underwent more weapons tests while engaging in flag-showing cruises to French possessions in North and West Africa, returning to Cherbourg in October after having traveled over 6,000 miles. At the end of 1932, she took up station in Cherbourg in the First Submarine Flotilla for further work-ups in order to fine-tune the boat for eventual fleet service. This process went on for another two years to try to fix the deficiencies noted above. During drills, it is reported that the main guns could be elevated to some 30 degrees, giving a maximum range of 30,000yards (17 miles), however her range-finder could only acquire targets out to a 7-mile horizon. Her main guns were able to fire some 2 ½ minutes after surfacing at a rate of 3 rounds per minute.  Surcouf finally entered service in 1934 after a successful long crossing from Conakry in French Guinea, Africa, to Cherbourg at a sustained speed of 14 knots. It was .assigned to the 4th submarine squadron (Escadron de Sous-marin --ESM) in Brest on June 1st, 1934. In 1935, the submarine was reassigned to the 2nd Submarine Flotilla in Brest from whence it sailed across the Atlantic on December 5 for a flag-showing cruise to commemorate the tercentenary of the French involvement in the West Indies. In 1937, the boat returned to Brest for extensive redesign work on the turret and superstructure undertaken in order to improve gun-laying, as well as surface and underwater stability, which entailed the raising of the conning tower and fire control director 0.85 meters. Hull and superstructure were reinforced to withstand the weight and shock of firing the main guns. From May to July 1938, Surcouf undertook a cruise in the Caribbean from where it transited to the coast of Africa. In 1939, the boat was in Dakar, Senegal at the westernmost extremity of Africa. When war broke out she was in the French Antilles. She started for home on the 26th of September, 1939, as part of the escort for British convoy KJ-2, sailing from Jamaica. Capitaine de Vaisseau Claude Huon has suggested that Surcouf's presence as part of the escort actually saved Convoy KJ-2 from attack by the 'pocket battleship' Deutschland in late 1939. Alerted to the possible presence of Surcouf by German Naval Intelligence, Kapitan Wennecker turned away from the convoy when one of his lookouts spotted a silhouette resembling a surfaced submarine at 21.27 on the night of 9 October, 1939. This tale has not been corroborated by any other references and must be consigned to legend until otherwise substantiated. On October 18, 1939 Surcouf returned to Brest for a major refit. She docked at Brest for repairs to the hydroplanes and rudders. While still undergoing improvements in Brest during the German invasion in June, 1940, Surcouf undertook an emergency evacuation to avoid capture by the advancing German forces, sailing on the surface on the single operative engine (one of the electric motors intended for underwater use) and arriving in Plymouth, England on 20 June where work was begun to prepare her for sea. In order to prevent the Germans from using French battleships and cruisers in an attack on Britain, Operation Catapult, was conceived: the destruction or capture of every French ship possible. The easiest stage of Catapult was the seizure of those French ships already in British ports. On July 3, 1940 the English seized the Surcouf , which was the only interned French warship that offered resistance. The struggle cost the lives of three British naval personnel and one French crewman. only two officers and 14 men of the crew agreed to remain as part of the Free French navy. The balance of the crew would be recruited among Frenchmen on British territory, a largely inexperienced lot, though attempts were made to find anyone with knowledge of the sea (including Breton fisherman and others). Surcouf went on her first cruise with her new crew in October, and their inexperience was revealed. A British officer and two signalmen were added to the crew as liaisons. This was common procedure with navies-in-exile serving the RN and worked well with other crews. Not so with Surcouf and tensions were always high.. This issue of alleged divided loyalties fueled conspiracy theories and wild rumors even including the alleged torpedoing of Allied vessels by rogue crew members. In 1941 she was re-commissioned by the Free French Naval Forces. Among her scratch crew of mainly young expatriate Breton fishermen, virtually none had ever been to sea in a submarine before, never mind one as complex and challenging to operate as the Surcouf. There was some hesitancy among the British naval staff as to how to utilize this unwieldy, strangely configured underwater craft. The deficiencies in her engines were reminiscent of the similar problems with the X-1. DeGaulle regarded Surcouf as the pride of the Free French Naval Forces, but the British Admiralty considered her to be an odd duck, and not particularly battle-worthy. After some brief training with the Third Submarine Flotilla in the Clyde, it was decided to transfer the boat to Halifax. She set sail from the Clyde on February 10th, 1941 Earlier she was bombed by German Heinkels while lying at Devon, but the damage had been quickly repaired. Several smaller Free French ships had been operating out of Halifax, acting as convoy escorts on the first leg of the long trans-Atlantic journey. Surcouf would sail eastward across the Atlantic from Halifax on April 1st seeing service as an escort for convoys HX 118 and SC 27. Detached from her duties during the trip, she was ordered back to Plymouth and would arrive on April 17th. Once more the issue of what to do with her was raised. Her original role of commerce raiding was irrelevant and she could not operate as a normal submarine, being to vulnerable to air attacks if placed on blockade duty. It was decided to send her to Bermuda, where she could act as a local escort and help patrol for German U-Boats, which were by then becoming active along Canada's eastern shores. She sailed on May 14th, 1941. Her first and only patrol in this capacity began on the last day of June and lasted three weeks. It was a total disaster, as the ship had repeated electrical failures and two diving mishaps almost cost the loss of the boat with all hands. Once chlorine gas flooded the sub, sickening the crew. Back in Bermuda it was recognized that the ship was in dire need of a major overhaul. With properly made spare parts inaccessible (she was one of a kind and had been built in Cherbourg) prospects were bleak. The nearest naval yard capable of making the necessary repairs and modifications was in the United States—avowedly neutral at the time. Under the terms of the recent Anglo-Allied Lend-Lease agreement Surcouf sailed to the United States and was docked at Portsmouth, New Hampshire’s naval yard late in July. Technically, the arrival of the Surcouf at an American naval base was a violation of the United States’ policy of neutrality in regard to the war raging in Europe. So in the weeks that followed, the Surcouf was refitted and its officers and crew mingled with the locals, but nothing could be said in public. For a while, the presence of the French sub was kept under wraps, but in early September, 1941 the Navy Department publicly acknowledged her presence. An article in the Portsmouth Herald explained that the vessel was being repaired under the terms of the Lend-Lease act as “one of a number of French submarines whose crews had decided to put in with Britain after France fell.” The Surcouf left the Portsmouth Naval Shipyard on Nov. 11, 1941. Despite Herculean efforts, only some of her problems had been addressed at Portsmouth. After a brief stopover in New London, Connecticut, Surcouf  briefly went back to Bermuda. After this stopover she received orders to proceed once more to Halifax to rendezvous with Admiral Muselier, commander of the Free French Navy. She arrived at Halifax on December 10th. The Admiral arrived a few days later with three corvettes, Mimosa, Alysse, and Aconit. On the 20th the little fleet, with Surcouf as flagship, left port, ostensibly on “maneuvers.” The maneuvers were more political and aggressive than a mere training exercise, however. On Christmas Eve, they landed sailors on the Vichy-controlled islands of St. Pierre and Miquelon, 25 miles off the southeastern coast of Newfoundland. Presumably the eight-inch guns of the sub were the principal intimidating threat that permitted the bloodless coup. These small islands were the last of France's North American holdings. This set off a diplomatic storm with the United States, and got President Roosevelt and General De Gaulle off on a very bad footing. In the end, despite the affront to the Monroe Doctrine (which implicitly indicates only the United States is allowed to invade countries in the Western Hemisphere), the conquest stood and Free France added the islands to its growing clientele. Surcouf returned to Halifax on January 11th, 1942. Note that the rumors of a hushed-up firefight between Surcouf and U.S. forces dispatched to restore the status quo in those islands must be relegated to the status of a myth, as there is little evidence that Surcouf could hope to defend herself on the surface against destroyers. FINAL CRUISE AND MYSTERIOUS DISAPPEARANCE It became readily apparent that the boat was still not totally seaworthy as more little defects kept coming to the fore. Orders came from Free French naval command to proceed to Tahiti, in the Pacific, notwithstanding the sub’s progressively unfit condition. It was perhaps thought that if the defects could somehow be remedied in Tahiti, she could assume her intended role attacking German merchant vessels trading in the Pacific. She arrived at Bermuda for a temporary stop over on February 7th, 1942. Yet more problems with the engines emerged during this trip, and it was apparent Surcouf was hardly able to dive. This did not detract from her capabilities all that much as she had theretofore almost always functioned as a surface ship. She set out for the Panama Canal on February 12th, despite her poor condition. She was just able to make 13 knots with her engines malfunctioning, but a return to Portsmouth was never considered due to the anger of her former hosts over the St. Pierre and Miquelon affair. While the submarine was fighting alongside the Allies between 1940 and 1942, she was plagued by rumors concerning her crew’s loyalty—it was said that the remaining crew still harbored resentment at the violent manner in which their vessel was taken over in 1940. There were even unconfirmed reports she had attempted to torpedo Allied shipping in convoys sailing from the US East Coast to Britain while stationed off Bermuda in May, 1941. This suspicion, however misplaced, along with the persistent hearsay about continued US hostility because of the alleged violation of the Monroe Doctrine facilitated the several conspiracy theories that surrounded the sub's mysterious disappearance. While the vessel had been making preparations for the trip to Tahiti, Roger Burney, the British Naval Liason Officer [BNLO] aboard the ill-fated submarine, warned the Admiralty that her crew were unreliable, and that they were openly talking about mutinying and defecting either to France or Martinique.- On February 18, Surcouf radioed her position and advised that she would reach Colon, Panama the following day in order to transit the canal. That was the last that anyone heard from her. The sea had swallowed her utterly along with an accounting of exactly how she perished, a tale that lay on the sea bottom along with the 129 crewmen. Not a single scrap of wreckage, body, or anything remotely connected with this giant vessel was ever found. According to historians and those who serviced her in Britain, Scotland, Canada, United States, and Bermuda, the super-submarine was not in sound cruising shape. During her visit to Bermuda, she had suffered a large fuel leak and seawater flooded into her battery compartment, that caused a serious chlorine gas problem. As noted above, part of the dilemma in maintaining her was lack of repair parts and supplies. She was full of French-made equipment, and France was under German control. So, an operational failure was a real possibility. The official version of the ships catastrophic end, accepted by many on both sides of the Atlantic is that the Surcouf was sunk in a nighttime collision with the American freighter Thompson Lykes about 78 nautical miles north of the Panama Canal entrance. While the Allies and Axis accepted this explanation during WWII, some latter-day skeptics assert that this conclusion does not confer with any of the ship logs or factual time frames. In support of the Thompson Lykes collision explanation, no other vessels were reported as lost in the area which further points towards the Surcouf as being the victim of this collision. In one report, the British liaison officer reported that officers in the conning tower of Surcouf often used an unshaded light to see the instruments. Possibly this could have been the flashes of light witnessed by crewmen aboard the Thompson Lykes. In addition, the position of the collision is approximately where one might have expected Surcouf to be. If the unknown vessel was indeed Surcouf, then it may be that she sank quickly with most of the hull intact and with virtually all contents of that hull trapped inside. The fact that no plates were ripped or torn from the Thompson Lykes suggests that the sub's hull may have remained intact but, with the gun turret and other vital areas flooded, she could have sunk rapidly in this state. As with most other accounts, this is speculation but it would explain why no wreckage or survivors were ever found. Another hypothesis, of French origin, argues that the Surcouf was the victim of the error of an American PBY Catalina seaplane, then on anti-submarine patrol in the vicinity of the reported collision with the Thompson Lykes. The PBY reported an encounter with what the crew thought was a German U-boat. There are even a few French theorists, still disgruntled over the manner in which their nation's vessel was appropriated , who allege that the attack on the Surcouf was deliberate, pointing to the American wrath over the use of their base to clandestinely prepare for the seizure of the Vichy-run islands. However, the US was at war with Germany and Japan at the time of the sub's loss and would hardly have sanctioned an attack on an asset of some possible use against her new foes in the Pacific—however deficient her operational status. ASSESSMENT OF SURCOUF AND THE EXPERIENCE OF OTHER NAVIES In retrospect, it can be seen that Surcouf suffered from a number of design flaws, many of which, however, may have been remedied by French repair yards had she remained on French soil. It is apparent, that the concept underlying her design, the submarine cruiser, was obsolescent by the onset of the Second World War and Surcouf's utility as an undersea torpedo attack vessel, as was utilized by the three major sea-powers during the war, was severely compromised by her configuration. The underwater cruiser participated in 15 raids, 15 escorts and 5 convoy patrols, and covered 35,000 miles for the Free French Naval Force (Les Forces Navales Françaises Libres ). During that period she essentially acted as a surface vessel, rarely submerging. There is an interesting fictional account of how Surcouf might have fared, had essential modifications been made, in “Strike from the Sea,” by Douglas Reeman. In the novel, one of Surcouf's intended sister vessels, here given the name Soufrière, was captured by British naval commandos from a secret base in the Straits of Borneo in the Pacific. She was then crewed by British submariners who had been prepped by interviewing some of Soufrière's former crew members who had defected to the Allies. Soufrière was snatched from under the nose of the Japanese, who were planning to use her as a commerce-raider. Many of the Surcouf's noted defects had been remedied in Soufrière, and she was utilized to good effect by the British submariners. Note that several other navies had planned to use very large submarines, but only the Japanese actually deployed them. Japan employed her monster subs as underwater aircraft carriers. Her I-400 class subs were able to carry three Aichi M6A Seiran aircraft underwater to their destinations. They were designed to surface, launch their planes, then quickly dive again before they were discovered. They also carried torpedoes  for close-range combat. The I-400-class was designed with the range to travel anywhere in the world and return. A fleet of 18 boats was planned in 1942, and work started on the first in January 1943 at the Kure, Hiroshima arsenal. Within a year the plan was scaled back to five, of which only three ( I-400 at Kure, and I-401 and I-402 at Sasebo) were completed. The planes could be deployed against enemy warships and merchantmen as well as shore-based targets. In fact, one of the rationales behind the boats was the intention to bomb the gates and locks of the Panama Canal at the commencement of any war with the United States so as to compel any relieving naval force from the Atlantic to take the lengthy route around Cape Horn. Apart from Japan, only two other navies considered the use of such massive subs. Mindful of the recent (1918) German employment of cruiser subs off her east coast, the United States Navy began considering a role for such long-range boats in 1920. Second into the cruiser sub design (after Germany) the United States built three cruisers,Argonaut, Narwhal and Nautilus. Argonaut had two 6-inch/53-caliber deck guns, four forward torpedoes with 16 torpedoes and two specially designed aft mine launching tubes with 60 mines. The only purpose built minelayer sub in the Navy, Argonaut was commissioned in 1928, and the latter two in 1930. The Narwhal and Nautilus were a slightly shorter but heavier design that had two aft torpedo tubes instead of mines and carried 24 torpedoes and the same gun armament. Argonaut was off Midway on December 7, 1941, and heard gunfire. Believing an invasion was under way, the crew discovered two DDs bombarding the island and twice attempted attack position but failed. She was then converted into a troop transport APS-1 and was mostly involved in landing raiders and agents until her sinking on January 10, 1943. Narwhal and Nautilus each went on several standard war patrols, but primarily the three boats were used for photo recon, raids, civilian rescues and supply missions rather than combat.  Notably Nautilus and Argonaut carried the Marines to Makin on August 16, 1942 for a raid. Both surviving subs were ordered to Philadelphia in January 1945 and scrapped by May. All in all, the Surcouf, for all its teething problems, might be considered the most promising design, and had the two follow-on sister boats been completed it is quite possible, as speculated by Reeman's novel, the defects may have been overcome. However, the concept had become outdated by 1942, when anti-submarine technology and tactics rendered such a large and inherently cumbersome vessel to be irrelevant, particularly in view of the advances in underwater detection and attack techniques using the torpedo. PAGE 13