Operation Source: Midget Submarine Attack on the Tirpitz, 22 September 1943 Part IV



The primary objective of Operation Source was to sink the Tirpitz, and although the battleship did not settle on the bottom of Kaafjord, it was disabled sufficiently to render it ineffective. One would have to conclude, therefore, that the mission was a success. The failure of X-5, X-8, X-9, and X-10 to reach their targets, and the inability of X-6 and X-7 to escape undetected, may have been due, in large part, to the Royal Navy’s not having conducted a full-mission profile during the preparation phase. If a ten-day towing exercise had been conducted during the preparation phase, the mechanical failures that manifested themselves during the assault (e.g., periscope leakages, ballast and trim problems, towline breakages, etc.) could have been identified prior to the mission and possibly corrected. This might have made the difference between escape and capture for the crews of X-6 and X-7 and life and death for the crews of X-5 and X-9. What eventually salvaged the operation was the professionalism of the crews, honed by months of repetitive training, and their boldness and perseverance in pressing home their attacks.

Were the objectives worth the risk? While the Tirpitz was in Trondheim, she had direct access to the Norwegian Sea and along with the Scharnhorst and Lutzow was capable of severing or damaging the maritime link between England and Russia. Just weeks before the X-craft raid, the Tirpitz and her escorts had attacked and leveled the entire 150-man Norwegian garrison at Spitsbergen, a strategically vital island east of Greenland. The Tirpitz’s guns had also destroyed a meteorological station, supply depots, thousands of tons of coal, shiploads of fuel, and a large port facility that supported the British fleet. This action caused concern, not because of the devastation, but because it meant that the British were unable to contain the Tirpitz and that it could sortie out into the Norwegian Sea and wreak havoc, apparently at will.

For almost a year the British, Russians, and Americans had been attempting to sink the Tirpitz. Even if she had never left her secure harbor for the rest of the war, the battleship would have presented a threat that could not be ignored. Although Operation Source cost the British seven dead and six captured, the Tirpitz never posed a significant problem again. The risks were clearly warranted.

Was the plan developed to maximize superiority over the enemy and minimize risk to the assault force? Operation Source began with one goal in mind—sink the Tirpitz. The air defense system surrounding Kaafjord was exceptionally dense, and even if a bomber had penetrated the antiaircraft guns, it would have had to drop torpedo bombs to pierce the hull where the ship was least armored. Both feats were highly unlikely. It became evident that there was only one way to deliver enough ordnance to destroy the battleship, and that was by submersible. Consequently, the X-craft was designed specifically for this mission. There were devices to counter the antisubmarine and antitorpedo nets, specially designed attack periscopes, and side charges with enough explosives to buckle the hull. Everything about the plan was aimed at maximizing the relative superiority of the X-craft. However, minimizing the risk in a submersible operation is difficult because to be exposed is to be captured or killed. Nonetheless, the British did everything they could to reduce this risk. They provided extensive intelligence to the planners, properly prepared the crews, and supported the effort throughout the operation.

Was the mission executed according to the plan? If not, what unforeseen circumstances dictated the outcome? The British were unable to fully execute the objectives of Operation Source due to the difficulties encountered while towing the midgets across the Norwegian Sea and owing to the defensive envelope that surrounded the Tirpitz.

On the open-ocean crossing, X-9 was lost at sea when the towrope between the parent submarine and the X-craft parted. X-8 had to be scuttled when she sustained damage, also related to a parted tow-rope. This meant that only X-10 would be available to attack the Scharnhorst and Lutzow. X-10 subsequently had mechanical problems and elected not to compromise the main objective (attacking the Tirpitz) by attempting to sink the Scharnhorst. Consequently, none of the secondary targets were engaged by the midgets of Operation Source.

The plan to sink the Tirpitz, however, was adhered to more closely. All three midgets, X-5, X-6, and X-7, were released approximately on time and began their transit without incident. Although the fate of X-5 is unknown, the other two X-craft arrived on time at the target. Unfortunately the Tirpitz was well protected by a massive antitorpedo net, and although both X-craft cleared the net and placed their charges, their inability to escape was almost preordained. The charges were set to explode less than one hour after placement. This provided no time for the X-craft to extract. The antitorpedo net, which had been relatively easy to enter (in both cases a matter of good fortune), was almost impossible to exit without exposing the midgets. Even if the two X-craft had escaped undetected, it is unlikely they would have gotten very far after the ordnance exploded at 0812. There were several hours of daylight remaining. The Germans could have sealed off the fjords, pursued the X-craft, and captured their quarry fairly quickly in the clear waters of the fjord.

What modifications to the plan could have improved the outcome? The major problem with the plan was having to tow the X-craft across the Norwegian Sea. Although this was unavoidable, it should have been rehearsed more fully and all the towropes should have been nylon or double-wrapped manila. To this day, Admiral Place also questions the viability of dropping the side charges underneath the Tirpitz as opposed to having the charges float upward against the ship’s hull. He wrote, “Why didn’t the Tirpitz sink? Several of us questioned the wisdom of releasing the [side cargos] to fall to the sea bed rather than having them float upwards to stick on the bottom of the target. The technical problem of ensuring they stick is easily solved. We were assured the ‘tamping effect’ would do more damage than simply blowing a hole—I remain unconvinced.” The Italians, who used a three-hundred-kilogram contact explosive, did more damage to the British battleships in Alexandria than the X-craft’s side charges of eight tons (total) did to the Tirpitz. It would appear Place’s assumptions were correct. Had the side charge demolitions been positioned as desired, the Tirpitz and her crew would have quickly settled to the bottom of Kaafjord, and the X-craft might have escaped.

Relative Superiority

The X-craft (both X-6 and X-7) reached the point of vulnerability at approximately 0400 when they encountered the first of the German defenses, the antisubmarine net. Although the midgets had relative superiority by virtue of their concealment, they were now within the envelope of detection, and the operation hinged on maintaining that clandestine posture. Unfortunately, clearing the antisubmarine net did not dramatically improve their chances of success; the midgets were still three hours from the target and the sun was coming up. Even though the enemy was not aware of the X-craft’s presence, the area of vulnerability continued to expand because the midgets’ probability of detection was increasing, and time was beginning to take its toll on the submersibles’ subsystems (i.e., ballast and trim, electrical, periscope, etc.).

At approximately 0700 (three hours after reaching the point of vulnerability), the X-craft penetrated the final obstacle, the antitorpedo net, and their degree of relative superiority improved significantly. Once they were inside the net, there was nothing the crew of the Tirpitz could do. There were no weapons in the Tirpitz inventory that could stop the X-craft that close to the ship. The massive guns were not able to train down on the midgets, and the Tirpitz’s crew was equipped with only small arms and grenades, neither of which could penetrate the steel hull of the X-craft. Once inside the antitorpedo net, all the crew of the X-craft had to do was release their side charges and escape. Unfortunately for the X-craft crews, once their presence was compromised they were unable to maintain relative superiority to effect their escape. This inability to sustain an engagement when compromised is a characteristic of subsurface attacks. They are the only special operations that are designed to maintain stealth throughout the engagement. Ground and air operations use stealth only as a means to gain access to the target. Once ground forces are on target, speed, not stealth, becomes the dominant principle. If ground operations are compromised immediately prior to the engagement, as the gliders were at Eben Emael, it does not necessarily follow that the attacking force will lose relative superiority. By applying speed and purpose, the operation can be continued and relative superiority gained and maintained.

In the case of Operation Source, success was not dependent on maintaining relative superiority long enough for the X-craft to escape, merely long enough to detonate the charges underneath the Tirpitz. Even after the charges were set, the probability of mission completion was not 100 percent. The commanding officer of the Tirpitz attempted to move his ship away from the charges, and although he partially succeeded, it was not enough to offset the eight tons of demolition. However, had the crew of the Tirpitz had more time, they could have completely negated the effects of the demolition by sailing from their anchorage. Relative superiority was maintained at this point by setting the time fuse on the side charges for only forty-five minutes, instead of four hours (to allow ample time for the X-craft to escape). At approximately 0812 the eight tons of demolition exploded, and the Tirpitz was rendered inoperable.

What makes the outcome of Operation Source so unusual is that it succeeded in spite of the large area of vulnerability. What should be clear, however, is that given another thirty minutes of vulnerability, X-6 would not have reached its objective. It was also this large area of vulnerability that probably affected the fate of X-5. Had we constructed a relative superiority graph prior to the operation and viewed success as recovery of the X-craft aboard the parent submarines, we would have seen a significant problem with the mission. From the time we reached the point of vulnerability until the time we recovered, the area of vulnerability would have constituted just under 50 percent of the mission. That is not to say that reaching a certain percentage of vulnerability automatically constitutes failure, but it should be a warning to the planners that the greater the area of vulnerability, the greater the frictions of war and the greater the possibility of failure.

Principles of Special Operations

Simplicity. During the planning phase of Operation Source, the Royal Navy constructed six X-craft and assigned each to a single target. This allowed the crews to concentrate on one objective. When X-8 and X-9 were put out of action, the Royal Navy remained committed to limiting the objectives. Instead of requiring X-10 to conduct attacks on both the Scharnhorst and Lutzow, the navy struck the Lutzow from the target list and continued with a focused attack. Although X-5, X-6, or X-7 could have been siphoned off to attack the Lutzow, this would have deviated from the final plan, reduced the size of the force attacking the Tirpitz (the primary target), and created more confusion.

The intelligence available to the crews of the X-craft was sufficient for the task but could have been better. They had extensive overhead photos, charts, hydrographic and astronomical data, schematics of the targets, and information on the guard routines; and the X-craft crews also knew that the German ship’s hydrophones were scheduled to be down for repairs. This detailed intelligence picture of the objective area allowed the Royal Navy to devise a plan that minimized the forces, employed effective tactics to circumvent German defenses, and used technology specifically tailored to the objective.

The one intelligence failure was the inaccurate analysis of the antitorpedo net surrounding the Tirpitz. Intelligence estimates concluded that the antitorpedo net extended to a maximum of sixty feet deep. Consequently, Place planned to overcome this obstacle by diving to seventy-five feet and going under the nets. Although divers were trained to cut through the net, this was not a viable option. Place later recalled, “I personally never really visualized we were going to have to cut through the net. There was very little hope of cutting English antitorpedo nets [much less German nets] because it was hardened steel, and it’s such a confusion of chain mail there that knowing where to cut is almost impossible.”

Place exercised good judgment in planning to go under the net. It was likely that the net would only extend to sixty feet. No “officer who possess a standard of judgement” would have assumed that an antitorpedo net would extend to the bottom of the seabed. Antitorpedo nets were designed to stop either air-dropped or submarine-launched torpedoes, neither of which were capable of diving under a sixty-foot-deep net and then homing on their targets. Therefore, even the best planner would probably not have foreseen this situation. This is a prime example of the frictions of war: poor intelligence sometimes combines with an unforeseen circumstance to create a situation for which one cannot plan or prepare. Even with perfect intelligence and the simplest of plans, one cannot foresee all the possibilities. Fortunately for the crews, they were able to overcome this obstacle and continue on with the mission.

Building on the intelligence picture, the Royal Navy created the X-craft for the purpose of defeating German defenses and sinking the Tirpitz. The use of new technology during Operation Source was essential to the mission’s success. Previous attempts by British chariots (manned torpedoes) to sink the Tirpitz had failed, primarily because the chariots (limited by range and diver exposure) required a support ship to insert them into the immediate vicinity of the target. This failure spurred the requirement for a longer duration, dry, midget submarine. The design of the X-craft considered all the operational parameters of this specific operation. The X-craft was small to negotiate the fjords and penetrate the antisubmarine nets. It was equipped with a wet/dry chamber to lock out the divers to cut the antisubmarine nets, and it had an assault periscope so slender that it barely rippled the calm waters around Kaafjord. Most importantly the X-craft carried two two-ton side charges specifically designed to destroy the fifty-three-thousand-ton Tirpitz. By limiting the objective to a single target, focusing the intelligence effort on that objective, and developing new technology to counter the defenses, the planners reduced Operation Source to its simplest form. When asked if he had any reservations about the plan, Godfrey Place responded, “No. I think we were quite confident. It seemed to be quite simple, really.” The planning phase, however, was just the beginning, and a simple plan does not equate to a successful operation without a great deal of preparation.

Security. Security was always a concern to the planners of Operation Source; however, it only mildly affected the daily operations of the X-craft crews. When they were training at HMS Varbel in Scotland, the operating area was relatively isolated. Precautions were taken to limit the exposure of the X-craft and their support ships, and the crews were provided a shallow cover story to tell the local townspeople. This notwithstanding, the Germans were fully prepared (antisubmarine and antitorpedo nets as well as daily anti-swimmer drills) to defend the Tirpitz against subsurface attacks from both conventional submarines and chariots. The security for Operation Source, therefore, need only have concealed the time frame of the operation and the unique capabilities of X-craft. This is not to imply that additional security was inappropriate; the less the enemy knew about the forces and means of employment, the better the chance the mission would succeed. In Operation Source, however, security was secondary to proper preparation and the need for repetitive training.

Repetition. John Lorimer, a crewman aboard X-6, when referring to repetitive training, said, “If you are going to do anything dangerous, the best way to accomplish it is to train, train, train, so that in the excitement of the situation you do the thing automatically.”

Operation Source had an advantage not normally associated with special operations: the crews had almost eighteen months to train, from 19 March 1942 until 5 September 1943. Although some of this training was basic familiarization, the largest portion was mission-specific. In the early months X-3 and X-4 were rotated weekly among the crews to conduct individual training. With the arrival of X-5 through X-10 in January through March 1943, each crew conducted daily training in preparation for the mission. Each aspect of the mission was rehearsed multiple times. This included passage training, net cutting, ship attack profiles, emergency procedures, escape and evasion training, and several limited mission profiles against nearby port facilities. As stated earlier the only shortfall in the preparation phase was the lack of a full-mission profile including a full tow. Repetition is essential to the success of any mission; however, repetition based on unrealistic profiles builds a false confidence that erodes quickly during an engagement. Some of the confidence exuded by the X-craft crews fell victim to problems that could have been identified through a more thorough training program: for example, X-8’s and X-9’s towline breakage and X-10’s mechanical problems. Nevertheless, the philosophy of train, train, train insured that four of the six X-craft successfully transited the Norwegian Sea and commenced their insertion into Norway on time. Then it was a matter of reaching the objective and surprising the enemy.

Surprise. The four X-craft that motored into Soroysund on the morning of 20 September 1943 all knew that the element of surprise was absolutely essential to the success of the mission. It was for this reason that Lt. Ken Hudspeth, whose X-10 was mechanically unsound to operate effectively, decided not to attack the Scharnhorst. Hudspeth knew that if his X-craft were compromised prior to the other midgets’ arriving on target, it would destroy his companions’ chances. One of his crewmen reported later, “Ken Hudspeth asked each of us whether we wanted to go in and do the attack and we all said, ‘Yes.’ But after consideration he said that we would be bound to be seen and that this would not only do us little good but might also spoil the chances of the others, which was more important.”

Hudspeth elected to remain on the bottom (at 195 feet) outside Kaafjord until the window for attacking the Tirpitz passed. If he heard no explosions by 0900, he intended to attack the Scharnhorst and attempt to complete his mission.

Place and his crew in X-7 achieved complete surprise, bypassing the antitorpedo net at approximately 0715 and releasing the side charges at 0730. It is conceivable that had X-6 not alerted the crew of the Tirpitz, X-7 could have escaped. Unfortunately, X-6 was spotted entering the antitorpedo swing gate at 0707, but confusion aboard the Tirpitz provided an additional five minutes before the crew began to react. Although surprise was not complete, the enemy was unprepared to react effectively, which provided Cameron in X-6 sufficient time to release his charges. Subsurface attacks have several advantages; however, as a rule, sustainability in the face of combat is not one. Once attacks are compromised, speed and purpose become everything and the opportunity for escape vanishes.

Speed. Speed in a subsurface attack must be balanced against the need to maintain surprise. If the attacker can remain undetected, then speed is only a function of the subsurface platform’s duration. This phenomenon is more prevalent in a swimmer or manned torpedo attack, where the duration of the diving rig and the temperature of the water directly affect the attacking element’s sustainability. In the case of Operation Source, however, speed was important because the mechanical difficulties (damaged periscope, ballast and trim problems, broken gyroscope) that plagued X-6 and X-7 became worse with time. Cameron, who had initially planned to cut through the antitorpedo nets, decided it would take too much time, time that would degrade his material condition and reduce the probability of success. Disregarding the risk, Cameron surfaced X-6 behind a picketboat passing through the antitorpedo net gate. What he lost in surprise he gained in speed. Once through the gate it took the crew of X-6 only ten minutes, from 0707 until approximately 0717, to reach the Tirpitz and release the side charges. The X-7, which remained undetected throughout the engagement, took only fifteen minutes to complete its mission once inside the antitorpedo net. Surprise and speed assured relative superiority, but it was the sense of purpose that assured success.

Purpose. In Operation Source, as in all special operations, the men involved in the assault must both understand the primary purpose of the mission and be personally committed to seeing it completed regardless of the costs. The primary purpose of Operation Source was to sink the Tirpitz. Everyone from the enlisted divers aboard the X-craft to Rear Admiral, Submarines, understood that, and they always remained focused on what was important. Beginning with the loss of X-9, the Royal Navy acted with the primary purpose in mind by not reducing the number of X-craft assigned to attack the Tirpitz. The Tirpitz was, after all, the primary target. Reducing the number of X-craft might have limited the damage sustained by the Tirpitz.

Later in the operation, Hudspeth showed he understood the primary purpose of the mission when he made a command decision not to attack the Scharnhorst. He had been ordered, as had the commanders of X-8 and X-9, not to compromise the mission before X-5, X-6, and X-7 had an opportunity to make their assaults on the Tirpitz. A compromise by Hudspeth would have alerted the nearby crew of the Tirpitz, and neither X-6 nor X-7 would have penetrated the antitorpedo nets. Place understood the purpose when he bypassed the Scharnhorst to remain on schedule to attack the Tirpitz. It was exceptionally difficult to pass up a sitting duck in favor of another target some miles away. Place, nevertheless, focused on what was important—the Tirpitz.

The men who volunteered for X-craft duty were screened to ensure they understood the hazards of the mission, and throughout training a sense of commitment to king and country was instilled into each man. This was not by accident but by design. The British, probably more than any other people, fully appreciate the value of patriotism to encourage a man to fight. Encouraging this sense of purpose, or duty, eventually paid dividends when it became a choice of safety or mission accomplishment. When the X-6, badly damaged from the long transit, was outside the antitorpedo net, the crew had the option of turning around and attempting to escape or pressing home their attack on the Tirpitz. Without hesitation the crew decided to attack. This resulted in all four crewmen being captured and spending the next eighteen months in a POW camp.

The crew of X-7 also realized that if they made the attack, escape was unlikely, for when the side charges exploded underneath the Tirpitz, the Germans would immediately seal off all escape routes to the open sea. Nevertheless, X-7 proceeded ahead and dropped her charges. The crews thought about scuttling the X-craft and attempting to cross the snow and ice to Russia, but in reality this was not an option. All the X-craft crews showed from the beginning of training until the completion of the mission that being committed to a cause greater than oneself is necessary for success in battle.

Operation Source was a classic special operation even though the submariners were not classic commandos. There was a specific target whose elimination was a military and political imperative. Men were specially trained, equipped, and supported. A simple plan was developed by limiting the objectives, using good intelligence to identify the obstacles, and then using technology and innovation to overcome those obstacles. The plan was kept concealed, rehearsed numerous times, and executed with surprise, speed (after X-6 was compromised), and purpose. The frictions of war continuously impeded the progress of the mission, but both the decision makers at the staff level and the submariners in the X-craft showed courage, intellect, boldness, and perseverance. All of this helped achieve and maintain relative superiority long enough to complete the mission.

Spec Ops: Case Studies in Special Operations Warfare: Theory and Practice – William H. McRaven (1996)