Elektroboot submarines (1935 – 1955)
Until the birth of Elektroboots, submarines had essentially been “submersibles”, i.e. warships with the temporary ability to submerge.
There was nothing in the Allied arsenal that could match what was thought to be the parameters of the new type of German U-boat then thought to being built in considerable numbers. Naval intelligence and encounters by Allied shipping revealed there to be a new and substantially faster U-boat (the Type XXI), that could remain fully submerged for unheard of lengths of time.
Suddenly the counter-measure days of simply ‘sitting on top’ of a U-boat until it ran out of breathable air were gone. The speed advantage a surface escort vessel had in chasing after a submerged U-boat was also reversed – these new high-speed U-boats could outrun some escort warships. And why, according to some prisoner of war, were the hulls covered with rubber sheeting ? Type XXI submarines were also far more ‘acoustically quiet’ than the Type VIIC U-boats, making them harder to detect when submerged (see U-480 below).
This was all rather baffling to the Allied Intelligence Services at the time. For those in military circles there were more questions than answers – and if counter-measures were to be devised those answers could not come quickly enough.
Today the streamlining of a hull is the expected norm and may even be regarded as unexciting and commonplace but the streamlined of U-boat designs of 1942 were far from ‘the norm’ and alternately agitated and excited Allied military planners to the point of ringing alarm bells.
The gifted rocket designer Hellmuth Walter, better known for his rocket-powered aircraft (most notably the Me 163 Komet) , had been advocating the use of hydrogen peroxide. This work had begun before 1939 and most of his early efforts were directed towards hydrogen peroxide for use as a submarine propulsion alternative to the reliance on the diesel-electric combination.
The first submarine – the first Elektroboot – using Walter’s hydrogen peroxide propulsion system was known as V80. Built at Kiel during 1939 – 40 it was driven by a single turbine (20,000 rpm), she was 77 ft in length and had a crew of 4.
Left: Illustration of V80
The V80 was built purely for research purposes and thus unarmed. V80 had a short life. She was taken out of service at the end of 1942, and was scuttled at Hela in March 1945, but not before successful sea trials and she had shattered the underwater speed recordata speed of 28 knots. The illustration tends to suggest this speed was achieved by streamlining and not the propulsion system alone.
Another Elektroboot was the Type XXIII submarines. Unlike the V80, which was only experimental, this class of U-boat (254 tons) was built in significant numbers and became operational. Their length (114 ft) was so small by contemporty U-boat standards that they could carry only two torpedoes (which had to be loaded externally).
Right: U-2367, a Type XXIII designed for coastal duties
To maximise production ‘parallel construction’ began at shipyards as far apart as France, Italy, German occupied USSR and Germany itself. The specifications demanded that it be transportable by rail are therefore not that surprising. Time pressures and restricted resource meant that it was partly based on the Type II coastal U-boat already in service and the proposed Type XXII which is also listed in the table below.
Designed as a small coastal submarines the Type XXIII operated in the shallow waters of the North Sea, Black Sea and Mediterranean Sea. In the closing pages of the war five Allied ships were sunk by Type XXIII boats with no losses to the attacking U-boats.
Sixty one boats of the Type XXIII were completed: seven Type XXIIIs were sunk before reaching full operational status; thirty one were scuttled at the end of the war; twenty were surrendered to the Allies and only three survived the war (U-2326, U-2353 and U-4706).
The fate of the 7 that were sunk is as follows:
- U-2331 – Oct 10 1944, disappeared while on training in the Baltic; cause unknown
- U2342 – Dec 26 1944, hit a mine in the Baltic
- U-2344 – Feb 18 1945, sunk after collision with U-2366 while on training in the Baltic
- U-2359 – May 12 1945, sunk by British aircraft in the Kattegat
- U-2338 – May 4 1945, sunk by British aircraft in the Baltic
- U-2367 – May 5 1945, sunk after collision with another U-boat in the Green Belt area
- U-2365 – May 5 1945, sunk by British aircraft in the Kattegat
The second of the elektroboots to see active service was the Type XXI. At 2,100 tons and with speed of 17 knots, and with a range of 15,500 nautical miles, these U-boats presented the biggest danger to the Allied shipping lanes (see U-2540 featured at the top of this page). It also made them the focus of a stampede between the “Allies” to capture as many intact examples as possible when Germany surrendered (May 1945).
Left: A model of U-3017, a Type XXI U-boat operated by Royal Navy as HMS N41
This method could have resulted in a turn-around time for each new vessel of only 6 months but the assembled U-boats were plagued with quality assurance problems which required extensive post-production repairs. The average completion time was 18 months. Mass production of the new type did not really get started until 1944. Had they been available 2 years earlier and in numbers over 20 they could have influenced the end of the war.
Nonetheless, 118 Type XXI were under construction by the end of the war and several were actually commissioned and operational. For instance, U-2511 and U-3008 were completed in time to go on war patrols. – but they were the only Type XXI to do so.
Features of the new Type XXI included;
- greater battery capacity
- improved dive times
- the ability to ‘sprint’ into position for an attack submerged (older type U-boats had to sprint into position of the surface making them vulnerable)
- the new hull design also reduced the boat’s radar ‘visibility’ when surfaced
- a hydraulic torpedo reloading system allowed all six bow torpedo tubes to be reloaded faster than a Type VIIC could reload one tube
- Type XXI could fire 18 torpedoes in under 20 minutes
- very sensitive ‘passive’ sonar were fitted to Type XXI
- it had better ‘facilities’ than previous U-boats, including a freezer to keep food fresher for longer
- deck furniture and fittings were retractable.
It is extraordinary to think that U-2540, a Type XXI U-boat (once of Nazi Germany’s Kriegsmarine) was, in 1957, raised from the seabed just off Flensburg Firth and recommissioned into the West-German Bundesmarine in 1960. She was used for research purposes and provided the basis for the later Type 205 and Type 206 submarine used during the Cold War (notable for their non-magnetic hulls). The U-2540 was only finally de-commissioned in 1980 and can now be seen as the only floating example of a Type XXI U-boat at the German Maritime Museum, Wilhelmshaven.
The cleaner lines of the Elektroboot German U-boats are best shown off in the above picture of a model Type XXI when compared with the Gato class, right. (A better picture resolution and appreciation of lines in question are better afforded by well photographed models than by trying to compare actual boats at sea or in harbour).
Right: Gato class note deck furniture
Contrasting American and Britsh submarines of the period, the aerodynamics are positively futuristic. By way of comparison Ameria entered the war with the Gato class fleet submarine built from 1940 – 1944 (2,424 tons with a range of 11,000 nautical miles).
The scale model is ideal to illustrate the obstructions and drag-inducing paraphenalia on the on the deck and around the conning tower.
The benefit of streamlining had not been realised when the Balao class – the succeror to the Gato class – was inaugriated (1942 – 1946). Below is an unaltered pre-‘GUPPY’ replica of a Balao class (2,424 tons, range 11,000 nautical miles).
Left: Balao class, note deck detail
After the war and as a result of acquiring and appraising Type XXI U-boats, the US embarked upon the Greater Underwater Propulsion Power Program – an upgrade of its subamines fleet. Known by the acronym “GUPPY”, post- GUPPY boats were distinctly more aerodynamic.
Right: The Balao class USS Greenfish after GUPPY alterations
The huge transformation of the Balao class submarines is best conveyed by the example of USS Greenfish (SS-351). Pictured above is the wartime profile of a typical Balao class submarine and to the right a Balao class after its streamlined ‘makeover.’ The USS Greenfish was commissioned in 1946 in pre-GUPPY form and returned to the shipyards in 1948 for the first of its alterations.
Below is a Table of all known Type XXI U-boats. Those U-boats numbers shown in black are known to have been completed, i.e. commissioned. Those with red numbers are U-boats ‘ordered’ and which may encompass those which were a). partially built, b) had only their keels laid or c). were simply paper orders, i.e. orders approving construction.
U-2513 was handed over to the American Navyin May 1945. It undertook no war patrols. First surrendered in Norway it then sailed to Lishally (Londonderry), Northern Ireland (7th June). In August 1945, the U-boat was transferred to the United States Navy. A year later, August 1946, U-2513 began an extensive overhaul at Charleston S.C. where she departed on 24th Sept. She then began six months of duty which included both evaluation tests of the U-boat’s design and duty in conjunction with the development of submarine and antisubmarine tactics. The Greater Underwater Propulsion Power Program (GUPPY) would be initiated because of the results of these tests. Pres. Truman was the only US President to set foot on and experience a dive in a U-boat (U-2513).
Post-war modernisation of US submarines under the Greater Underwater Propulsion Power Program proceeded in seven stages: GUPPY I was to reduce hydrodynamic drag; GUPPY II, was to fit the recently perfected snorkel, GUPPY IA was a cheaper alternative to the GUPPY II; Fleet Snorkel again related to the snorkel; GUPPY IIA was similar to GUPPY IA. These were then followed by GUPPY IB, and GUPPY III – and in the rather odd order shown here.
The promise of an alternative propulsion system free of any reliance on the need oxygen was very appealing. There is no doubt that the Americans and British were determined to exploit this possible Holy Grail for themselves while denying the latest German submarine technology to the Russians. For their part the Russians had a correspondingly selfish attitude to the ‘spoils of war.’
In practical terms the Russians had captured a considerable number of unfinished Type XXI U-Boats in the shipyards in Danzig, and had as a result gained access to the plans for, and a full-scale model of a Type XXVI U-Boat (U-4501 through to U-4600). These variants would have been a larger and longer range version of the Type XVIIB U-Boat shown below.
Both the Type XXVI and the Type XVIIB were to be fitted with the HTP, or high test peroxide, power plant. In 1944 it was not fully appreciated just how dangerous this system could be in a confined space – a realisation that came only after hostilities ended and testing began.
Derivatives of hydrogen peroxide power are not limited to submarines as the earlier reference to the Me 163 Komet indicates. One form, HTP or high-test peroxide, is a high (85% to 98%) concentration solution of hydrogen peroxide, with the remainder predominantly made up of water. In contact with a catalyst, it ‘decomposes’ into a high-temperature mixture of steam and oxygen, with no remaining liquid water.
Although extremely combustible it is still used today as a propellant for rockets and torpedoes, and has more publicly seen in Vernier engines, i.e. the thrusters used for spacecraft to adjust their position.
However, in 1945 the emphasis was on submarines. Germany’s northern ports fell under the British occupying force jurisdiction and a variety of U-boats were discovered – the Type receiving the highest priorities were the Walter powered boats, e.g. Type XVIIA and Type XVIIB.
Left: a Type XVIIA underway
The Type XVIIA came as two variants’, one the Wa 201 was 128 ft long, and the second (Wk 202) was 120 ft long (the types were later followed by the Type XVIIB).
U-792 was a Wa 201 variant, launched on 28 Sept 1943 and commissioned on 16 Nov 1943. She was 128 ft long, and displaced 309 tons. She was wrecked, 3 May 1945 and later broken up
U-793 was also a Wa 201 variant; launched on 4 March 1944 and commissioned on 24 Apr 1944.
U-794 was a Wk 202 variant of 120 ft long, displacing 259 tons, she was launched on 7 Oct 1943 and commissioned on 14 Nov 1943.
U-795 was a Wk 202 variant, 128 ft long, launched on 21 March 1944 and commissioned on 22 Apr 1944.
Three intactType XVIIBU-Boats (U-1405 to U-1407) fell within the British Sector after May 1945 with 2 or 3 more, U-1408 to U-1410 partially finished. These U-boats displaced 337 tons, were 136 ft in length 136 ft and, powered by the fabled HTP [high test peroxide] system had the astonishuing submerged speed of 25 knot.
Anglo–American plans suffered a setback when U-1405 to U-1407 were scuttled by their crews following the German collapse at the end of the Second World War.
Right: U-boat, U-1406, a Type XVIIB allocated to the US being dismantled after World War II
All three were raised and salvaged in June 1945. U-1407,which was allocated to Britain, was repaired d and together with its inventor Prof. Hellmuth Walter, transported to Vickers in Barrow-in-Furness for further assessment and refit. There Vickers under the supervision of Prof Walter, fitted her with a new and complete set of machinery (also captured in Germany). She was first known as HMS N41 but was later re-commissioned into the Royal Navy as HMS Meteorite.
U-1405 (pictured above) was raised, and transported to theUSand then broken up sometime after 18 May 1948.
The fate of U-1406 is not known with certainty to the author but U-1407 was transported to Britain and served as HMS Meteorite until 1949
Of the remainder, U-1408 to U-1410 were incomplete when the war ended and the contract for U-1411 to U-1416 was cancelled before construction began
No good representational pictures are freely available of the Type XVIIB save for the one above chosen for its depiction of the complete hull.
Germany also experimented with deadening the echo reply of ASDIC used by Allied warships. Some sources have disparaged these attempts at coating the entire hull in rubber sheeting as ineffective but recent evidence, circa 2004,  indicates it was in part so effective that the methodology has been adopted by other sea powers since 1945. A television programme regarding the wreck of the U-480 underscored she might have had some success due to this cloaking device prior to her sinking, not off the Isles of Scilly (south west England), as originally thought, but deep in the English Channel later in 1945.
The rubber sheeting is in fact a series of tiles glued to the specially prepared hull of a submarine. Termed Anechoic Tiles each tile has a series of perforations matching the signature – in the case of U-boats – the wartime frequencies used by ASDIC. The anechoic tiles both absorb the sound waves of ‘active sonar’ (pinging) and lessen any sounds made by the vessel, e.g. its engines. The latter reduces the range at which it can be detected by passive sonar.
Experimenting with rubber coatings first began with U-11 in 1940 followed by U-67 in 1941. The 4-millimetre thick rubber coatings were variously applied to the entire hull, the conning tower but not the deck and permutations thereof. Two notable problems were that the coating could become detached creating sonar attractive turbulence in the water and secondly it was found to have decreased the speed of the boat.
It was not until late 1944 that the problems with the tile adhesive were mostly resolved – a process that took several thousand hours of hull cleansing, gluing and riveting on the U-boat. The first U-boat to test the newer type adhesives was U-480, a 757 tons Type VIIC U-boat.
Other U-boats that received the same rubber tiles included:
U-485, U-486 (a Type VIIC), U-1105 (a modified Type VII-C/41), U-1106, U-1107, U-1304, U-1306, U-1308 (the last Type VII/41 built) and three small Type XXIII ‘elecktroboots’; U-4704, U-4708 and U-4709.
After the war the technology was not utilised again until the 1970s when the Soviet Union ressurected the technique for its slightly noisy subs. Modern Russian tiles are about 100 m/m thick, and apparently reduced the acoustic signature of Akula class submarines by between 10 and 20 decibels, (i.e. 10% to 1% of its original strength).
By 1980 both the US and Britain were applying anechoic tiles to their submarines perhaps indicating that the gains outweighed the drawbacks of weight, cost and any increased ‘drag’.
Research Programme in the 1950s
The recovery of U-1407 was the impetus for a British research programme which resulted in the construction of two experimental submarines, HMS Explorer and HMS Excalibur (ordered in 1947 and completed in 1954 and 1958). She displaced 1,000 tons submerged and was 178 ft in length. They were built for speed trials and both were unarmed. The HTP engines were essentially steam turbines, with the steam being generated by the interaction of HTP with diesel oil and a catalyst.
Both boats suffered from many teething troubles to the extent that her first captain never took her to sea and the duo were comically referred to as “HMS Exploder” and “HMS Excruciator” (both were decommissioned in the 1960s). 
Historically, HTP is significant, if not a milestone, as the first attempt at AIP (Air Independent Propulsion). AIP is a generic tem for closed loop engines. It is a term that encompasses technologies such as oxygen substitution or Stirling Engine, which allows a submarine to operate without the need to surface, use a snorkel, or access atmospheric oxygen. Coincidentally, these technologies also significantly reduce the noise level of the submarine and thus their rate of detection.
The Soviet Union built a single, semi-successful example of a Walter-cycle submarine known in the West as “the Whale,” but their most serious efforts were focused on a closed-cycle diesel plant based on the German Kreislauf system. Together with their own pre-war researches this eventually led to the 650 ton (540 ton ?) Soviet Quebecclass of 1956.
Left: Soviet Quebecclass, length 183 ft
This class of submarine used ‘stored liquid oxygen’ (LOX) to sustain the closed-cycle operation for diesel engines. An experimental prototype submarine, the M-401, was launched in May 1941 but the conflict with Germany (June 1941) suspended the programme. The exhaust gases from the diesel engine were compressed and the carbon dioxide extracted and dumped overboard, before the purified gases were mixed with stored oxygen and fed back into the engine (closed loop). The M-401 made 74 cruises in the Caspian Sea including 68 dives and covered 360 nautical miles, so in that regard it was successful.
This led to 30 boats based on this system being built between 1953 and 1957. However, their safety record was so very poor that they were known by their crews as “the cigarette lighters” and withdrawn from service by the early 1970s.
Submarines fitted with nuclear reactors sounded the death knell for HTP power. When the US Navy began building nuclear powered submarines nations using the HTP technology abandoned their projects. In Britain the HTP project was abandoned, and Explorer and Excalibur were scrapped
The Dream Lives On
Despite the advent of nuclear power as the preferred propulsion system for submarines there remains a niche market for AIP (Air Independent Propulsion). Diesel-electric powered submarines need some device if they are to evade detection by searching anti-submarine vessels using electronics for ASW (anti-submarine warfare).
Everyone is familiar with films depicting the ‘ping, ping’ of a surface vessel using ‘active’ SONAR (Sound Navigation and Ranging), to seek out a submarine. This depends on emitting a stream of pulse and waiting for the sounds to be reflected back to the search vessel.
The second form of SONAR is passive sonar which emits no signal but listens for the sound made by vessels, e.g. its engines vibrations or propeller noise.
Both forms of sonar are used as ‘acoustic location’ devices and to measure the echo characteristics of “targets” in the water, e.g. speed, depth, range etc.
The acoustic frequencies used in sonar systems vary from very low (infrasonic) to extremely high (ultrasonic).
Contrary to popular perceptions of the ‘silent deep’, the ocean is, for acoustically sensitive equipment, a very ‘noisy’ environment. In addition to background noise, water has differing densities depending on depth and global geography. Submarines can ‘hide’ in this denser water. A heavier-than-water submarine could hide even more easily (all submarines are currently lighter-than-water).
‘Acoustic countermeasures’ available to a submarine can include sound-absorbing materials to cloak or nullify surfaces thatmight ‘reflect’ when underwater. This was first seen in U-boats of World War II and then Russian Juliett class and Kilo class (see Chinese subs URL ?).
‘Electronic countermeasures’ available to a submarine include noisemakers to disrupt/confuse the pursuer.
For this assortment of countermeasure to be successful, however, the conventionally powered diesel-electric boat has to remain submerged. In spite of advances in battery life AIP systems are still required. They are capable of propelling a craft along at 5 knots while running almost silently and using up little or no oxygen.
From earlier articles on this blog site it will be apparent that‘cavitation’ and the give-away noise it produces has presented all Navies with a problem. One way around thathas been sophisticated propeller designs but another is to abandon the propeller altogether.
“Quiet Electric Motors” as used in modern submarines are not super-suppressed normal AC motors complete with brushes and armatures that are noise dampened – in fact they QEM has no moving parts at all. Alternately termed Integrated Motor Propulsion (IMP) and Magneto-Hydrodynamic Drive (MHD).
The ‘magnetohydrodynamic drive’ is more often associated with a form of submarine propulsion utilising a Kort nozzle or a Pump-jet. It works on the basis of an electric current being passed through seawater in the presence of an intense magnetic field. This interacts with the magnetic field of the current through the water. The effect is for the seawater to repel pushing the water out towards the stern thus accelerating the vehicle in the opposite, i.e. forward, direction.
MHD is attractive because it has no moving parts, which means that a good design will render the submarine ‘silent’ – and reliable, efficient, and inexpensive (especially so if it also creates drinking water and oxygen as by-products). 
Magnetohydrodynamic drive is analogous to the impulse drive which featured in the TV science fiction series Star Trek (the ‘impulse engines’ giving sub-light speeds).
Integrated Motor Propulsor (IMP) is similar to MHD but appears to be more readily found as the motor for torpedoes. The IMP is described as a ‘hybrid propulsion system’ which incorporates a radial-field electric motor (as does the MHD) but directly into the torpedo propeller jet. It is claimed this completely eliminates an internal motor which would normally require seals to prevent the ingress of water and torpedo failure. 
Bolting the drive unit onto the back of the torpedo body and replacing the normal propeller is said to increase its ‘stealth’ potential. The closed-cycle propulsion is said to be quiet, wakeless, and depth-independent.
In a cost conscious time, with its rechargeable energy source, it will help reduce naval exercise expenses by providing more affordable training opportunities because of its lower ‘total ownership costs.’
Ten years ago (202) Germany launched a Type 212A submarine and soon after launched a second for the German Navy (2003). 
U 31 and U 32 are Type 212A submarines, displacing 1,830 tons and are 183 ft long. Both are powered by a single diesel engine and an electric motor driven by two ‘fuel cells.’ Hull surface are covered in a special, non-reflective paint that absorbs ultrasounds coming from the sonars of other submarines. Type 212 features a cavitation-free propeller and have a submerged speed of 20 kts.  U 32 was the first non-nuclear submarine to stay submerged for two weeks.
Sweden’s Gotland class submarine (1,500 tons) was the first AIP submarine to enter regular service in 1996 with a speed of 20 kts when submerged. It features a “X” rudder said to give it greater manoeuvrability especially when close to the sea bead. (see S1000 China page). “Several weeks” is the underwater endurance claim for the Gotland class.
“Fuel Cells” are another form of AIP. In simple terms, a fuel cell is an electro-chemical conversion device that combines hydrogen and oxygen to produce water, electricity, and heat. The fuel cells on the U 32 are placed on the outside of the hull and are designed so thatin case of a disaster they explode on the outside thus minimising the risks for the crew.
Decades ago the principle of electricity and water was used for welding high melting point metals like platinum. An electric current was used to separate hydrogen and oxygen and the resulting gases used to fuse the metal. Fuelk cells are not that dissimilar.
Fuel cells are already seeing a number of promising applications in the space and automotive industries – many believe thatfuel cells offer the best potential for developing more efficient AIP systems in the future.
There are several alternative configurations for fuel cells, but the system that has attracted the most attention for submarine propulsion, is the “Polymer Electrolyte Membrane” (PEM) fuel cell. It has a low operating temperatures (80° Centigrade) with relatively little waste heat.
- In a PEM device, pressurized hydrogen gas (H2) enters the cell on the anode side, where a platinum catalyst decomposes each pair of molecules into four H+ ions and four free electrons.
- The electrons depart the anode into the external circuit – the load – as an electric current.
- Meanwhile, on the cathode side, each oxygen molecule (O2) is catalytically dissociated into separateatoms, using the electrons flowing back from the external circuit to complete their outer electron “shells.”
- The polymer membrane thatseparates anode and cathode is impervious to electrons, but allows the positively-charged H+ ions to migrate through the cell toward the negatively charged cathode, where they combine with the oxygen atoms to form water.
Thus, the overall reaction can be represented as 2H2 + O2 => 2H2O, and a major advantage of the fuel-cell approach is that the only “exhaust” product is pure water. Since a single fuel cell generates only about 0.7 volts DC (direct current), groups of cells are “stacked” together in series to produce a larger and more useful output. The stacks can also be arrayed in parallel to increase the amount of current available.
Rockets and Missiles
Hydrogen peroxide – and its derivative fuel mixtures – met with more success when applied to aircraft and space. A good deal of sensational progress was made during the 1950s when the advantages of this technology were applied to aircraft, satellite launch rockets and missiles. For a brief timeBritainhas its own satellite and space exploration programme.
With Russia and the USA capturing or ‘attracting’ all the scientists after the war Britain developed its own rocket expertise based on kerosene / hydrogen peroxide engines. These rocket engines were very successful, inexpensive and very efficient – if not ingenious.
The exhaust from kerosene / peroxide burn-off is predominantly water. This results in a very clean exhaust (second only to cryogenic LO2/LH2) and a distinctive clear flame. The low molecular mass of water also helps to increase rocket thrust performance. Other characteristics of this approach yield “regenerating cooling” of the engine nozzles before combustion (reducing wear and failure rates). The result was a rocket motor without the usual major engineering problems and compromises.
The following table shows some of the British rockets designed and built in the 1950s.
Blue Streak, which promised so much, became the basis around which the European efforts into space exploration began. Beginning with the European Launcher Development Organisation (ELDO) in 1964; this then merged, in 1975, into the European Space Agency (ESA).
On the manned aircraft front, the Saunders-Roe SR.177 and Saunders-Roe 53 were contenders for large contracts requiring an all-weather supersonic interceptor. Jet engines were still in their infancy and ‘thrust levels’, compared with today, were very modest, e.g. Rolls Royce Avon 6.500 lb.
The experimental SR.177 and ST 53 had two distinct engines; a jet turbine and a separate rocket engine using a hydrogen peroxide / kerosene mixture and was much faster than any of its rivals (among them the English Electric Lightening), for the NATO contract.
The changes needed to make it suitable for European action rather than Colorado or Californian conditions had ‘unbalanced’ the plane and put heavier loadings on the stubby winglets and altered the ‘stall’ characteristics.
Of Germany’s 916 Starfighters (F-104), about 270 crashed, i.e. just under 30% of the total force; almost half were fatal (110 pilots were killed). Canada, which operated its F-104 in Northern Europe, had an even higher attrition rate, losing over 50% of its fleet of 200 single-seat F-104s.
Used at sea and in the air – in both manned, e.g. Me Komet 163 and unmanned craft, e.g. the V2 – the methodology of using hydrogen peroxide (and its limitations) were well-known by the 1950s – but its adaptability ensured it was never forgotten or ruled out for many solutions.
From 1955, with the sinking of HMS Sidon, to the sinking of the Russian submarine the Kursk, Aug 2000, hydrogen peroxide, in one form or another, has been used as a propellant for high speed torpedoes.
Both boats appear to be victims of internal explosions caused by torpedoes powered by HTP. Fortunately, HMS Sidon was surfaced and tied up in dock when loading her torpedoes.  Nevertheless, her explosion and rapid sinking claimed 13 lives. Had she been at sea and/or submerged the death toll might has been as total as the Kursk’s.
Britain’s latest submarince, HMS Astute, incorporates a hull covered with accoustic tiles. The original German version was made up of one metre square tiles perforated with with 2 m/m and 4 m/m holes (tile thickness unknown). Modern Russian tiles are about 100 mm thick (approx. 4 inches). HMS Churchill was the first UK submarine to be treated with acoustic tiles in 1980. One can deduce that most or all of the Royal Navy’s submarines have been similarly treated since then. It is thought that the most modern tiles utlise both oval and circular holes to extend their ‘cloaking’ and sonar defeating potential, however, other technical details are not available. The early German version had problems with regard varying sonar reflecting characteristics at different depths – so one asumes that is a ‘wrinkle’ that has now been cured.
Enigma machines – 3 of these German encoding machines were captured during World War 2. The first came from U-110 a captured Type IXB U-boat, by the Royal Navy in the North Atlantic near Ireland, in May 1941. The second cane fromU-559 (a Type VIIC U-boat) on 30 Oct 1942, engaged 70 miles north of the Nile Delta. Both U-boats surfaced briefly and sank shortly afterwards.
The third Enigma machine was captured from U-505, a Type IXC U-boat, by the United States Navy off the coast of Rio de Janeiro on June 4th 1944. On this occasion the U-boat was not successfully scuttled and she was taken in tow to the Bahamas. This Enigma machine had the latest variations and an extra layer of cipher protection.
However, all of the above were the Naval version as opposed to the Army version. The first Army version was captured by the Polish intelligence service in 1928. Although an early version, Polish intelligence had broken the Enigma code by 1932. It was brought to England in 1939 when Germany invaded Poland, and although it reportedly lacked some components, i.e. internal rotors, it formed the basis of the work for code-breaking at Bletchley Park until U-110’s capture.
 US “Naked Science” television episode “Stealth Submarine”. U-480 was found in 1997. After sinking possibly 3 warships it is thought sitting in wait on the bottom but with strong Channel currents, she drifted into an Allied minefield.