The Forgotten British Weapon That Sank German Cruisers in Open Daylight

The night of 19th October 1942 is black and bitterly cold over the English Channel.

A British motor torpedo boat MTB236 sits low in the water roughly 40 km off the coast of Normandy.

Her engines cut to a whisper, her crew listening.

Somewhere to the east, the faint thrum of high-performance German diesel engines is growing.

Not one engine, several.

The familiar silhouettes of Schnelb boot, what the British call eboats, are closing fast, their sleek hulls barely kissing the surface of the sea as they push towards the convoy lanes at speeds that most warships of the era can only dream about.

The commander of MTB236 has a decision to make.

He is outnumbered, outgunned in terms of raw firepower and in open water against adversaries who have spent three years perfecting the art of fast attack warfare in these very waters.

In almost any previous engagement this year, the sensible response would be to run, to turn hard to port, push the throttles to maximum, and pray that British engineering is fast enough to survive another night.

But tonight is different.

Tonight, MTB236 is carrying something new, something that German eboat crews have not yet encountered, something they are absolutely not prepared for.

What happens next lasts less than 4 minutes.

The Eboats, upon detecting the British vessel and closing to attack range, suddenly break formation.

They do not press their assault.

They turn away.

All of them accelerating hard into the darkness in the opposite direction, abandoning whatever mission brought them this far west.

MTB236 has not fired a torpedo.

Her crew has not even discharged their deck gun in anger.

And yet the German flotillaa, experienced an aggressive naval warriors who have terrorized Allied shipping for years, has fled not because they were defeated, because of what they saw, because of what they heard, because of what they felt approaching them through the dark water.

This is the story of the Homeman Projector, the power jet flamethrower, and most devastatingly of all, the coastal forces development units short-range incendiary weapon.

A device that in the right hands and the right conditions could turn the surface of the sea itself into a wall of fire.

It is a story about British ingenuity under pressure, about the peculiar demands of coastal warfare, and about one of the Second World War’s least celebrated but most psychologically effective weapons.

It is also a story about fear.

Specifically, what happens when men in fast boats made primarily of wood and petrol suddenly find themselves staring at a weapon designed to set the sea on fire? To understand why this weapon existed at all, you need to understand the problem it was designed to solve.

By 1941, the German criggs marines eboat arm, the Schnel booter, had become one of the most effective and troublesome adversaries facing the Royal Navy in home waters.

These were not the lumbering surface combatants of traditional naval warfare.

The Schnel boot were roughly 35 m in length, displacing around 100 tons at full load, and powered by three Dameler Benz diesel engines that together generated over 6,000 horsepower.

At full speed, they could reach 39 knots, roughly 72 km per hour, making them faster than virtually every vessel the Royal Navy had available to counter them in coastal waters.

Their primary weapons were torpedoes, and they used them to devastating effect against Allied convoys running along the east coast of England and through the channel.

Between 1940 and 1942, eboats sank dozens of merchant vessels, tankers, and smaller warships.

The loss of the landing craft convoy known as Exercise Tiger in April 1944, where German Eboats sank two LSTs and damaged a third, killing an estimated 749 American servicemen in a single night, would later become the most notorious example of what these vessels were capable of.

But by that point, the threat had been well established for years.

The Royal Navy’s answer was the Coastal Forces.

A vast and rapidly expanded collection of motor torpedo boats, motor gun boats, and motor launches built from British oak and Burmese teik powered by packered petrol engines licensed from America and crewed largely by young RNVR officers who had been civilians barely 2 years before.

These men were brave, resourceful, and increasingly skilled.

But they faced a fundamental tactical problem that no amount of courage could entirely resolve.

The eboat outclassed the MTB in almost every meaningful category except one.

At very close range in a fastmoving engagement at night, a well-armed British motorboat could theoretically bring enough firepower to bear to destroy a German vessel.

The difficulty was getting to that range.

At medium and long range, the eboat could simply disengage, turning at full speed and disappearing into the darkness before any British vessel could close the gap.

What was needed was not a weapon that could reach further, but a weapon that could alter the fundamental calculus of the engagement.

Something that could make a German commander think twice about disengaging.

something that could, if conditions allowed, turn the act of flight into something more dangerous than standing and fighting.

The answer came from an unlikely source.

The development of British coastal forces weaponry was partly the responsibility of the Admiral’s Department of Miscellaneous weapon development, known informally and with considerable fondness by those who worked there simply as DMWD.

This was the organization that would eventually produce such eccentric but effective innovations as the hedgehog anti-ubmarine mortar and the famous bouncing bomb precursor charges.

It was staffed by a mixture of career naval officers, scientists seconded from universities and civilian engineers who approached the problem of warfare with something closer to the mentality of inventors than to that of soldiers.

Their brief was essentially to solve the problems that conventional naval architecture and ordinance could not.

The specific problem handed to the relevant team working in close collaboration with the coastal forces development unit based at HMSB in Waymouth was deceptively simple to state.

How do you stop an eboat from running away? The answer they arrived at after considerable experimentation and a number of prototypes that range from the workable to the frankly alarming was something they called the short range incendiary weapon later classified under the broader designation of power jet flame projector systems.

What it was, in essence, was a way of throwing burning petrol through the air and across the surface of the water at a high speed, in sufficient quantity and over sufficient range to create a barrier of fire that a wooden high-speed vessel filled with diesel fuel and crew would be extremely reluctant to cross.

The mechanism was derived from existing flamethrower technology, specifically from the lifebo man portable infantry flamethrower and from engineering principles shared with the crocodile tankmounted system then under development for armored use.

At its core, the naval system consisted of a pressurized fuel tank, typically containing a mixture of thickened petroleum, similar in composition to early napalm, though the British did not use that American term, and a projector nozzle mounted on a trainable mount that could be aimed across the beam of the vessel.

The ignition system used a small charge of cordite to initiate combustion at the nozzle mouth, ensuring reliable ignition even in high winds and wet conditions.

The thickened fuel was the critical innovation here.

Standard petrol when projected through the air disperses too quickly to be effective at range and extinguishes itself on contact with water.

The thickened mixture behaved differently.

It maintained cohesion during flight.

It spread on impact with a water surface rather than sinking.

And most importantly, it continued to burn.

A single projector discharge could lay a burning slick across roughly 30 to 40 m of water surface within seconds with individual burning patches persisting for between 45 seconds and 2 minutes depending on sea conditions.

in calm water.

The effect was described by those who witnessed tests as looking like the sea itself has caught fire.

The psychological impact of this image at night at close quarters on men aboard a wooden vessel moving at 30 knots is not difficult to imagine.

Production of the system was initially handled by the Lagand Motor Company, the British motor car manufacturer better known for producing elegant pre-war saloons whose engineering workshops in stains, middle sex had been converted to war production.

The company’s expertise in precision engineering and fuel system manufacture made them a logical choice for a weapon whose reliability depended entirely on the consistent behavior of its pressurized fuel delivery system.

Later production was shared with several other contractors whose names remain partially classified, though estimates from available Admiral T procurement records suggest that somewhere between 180 and 250 complete systems were eventually manufactured with spares and components taking total production to significantly higher numbers.

The system weighed approximately 340 kg fully loaded, roughly equivalent to a small car engine, and required a permanent mounting on the aft deck of a vessel.

The projector nozzle itself had a diameter of approximately 76 mm, and the projector could be traversed through an arc of 120°.

Maximum effective range was assessed in trials at approximately 60 m against a water surface target, though records suggest that in favorable conditions, skilled operators achieved burning coverage at ranges approaching 80 m.

The fuel capacity per discharge cycle was sufficient for 3 to five full projections before the system required reloading from the vessel’s reserve tanks.

a process that took two trained crew members approximately four minutes to complete under combat conditions.

The weapon was first deployed operationally in the late summer of 1942 with the eighth and ninth motor torpedo boat flotillas operating out of Felix Stowe and Great Yarmouth.

The crews who trained on the system were initially skeptical.

Experienced coastal forces men tended toward weapons that killed the enemy directly and definitively, and there was a degree of professional disdain for anything that seemed more theatrical than lethal.

That skepticism did not long survive actual contact with Eboats.

The first confirmed operational use in which the weapon influenced an engagement occurred in the waters off the Hook of Holland in the early hours of September the 6th, 1942.

An MTB on patrol encountered a pair of Eboats at approximately 200 m and attempted to close for a torpedo attack.

The German vessels, as was standard practice, began to disengage at high speed.

The British commander ordered the projector fired across the predicted escape path, not at the eboats directly, which were beyond effective range, but ahead of them in the water through which they would need to pass to escape.

The leading eboat altered course violently to avoid the burning slick, cutting across the stern of her consort.

No torpedoes were fired, no guns were discharged in anger on either side.

But the encounter was reported up the German chain of command with unusual emphasis and subsequent ebo patrol reports from the area contain references to foyer shifer fire ships in terms that suggest genuine alarm among experienced crews.

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By the winter of 1942 and into 1943, the weapon was being used with increasing tactical sophistication.

Coastal forces commanders had identified that the projector’s greatest value was not as a direct anti-hship weapon.

It was as a tool for channeling enemy movement.

Eboats that encountered burning water ahead of them were predictably reluctant to cross it, even when the flames were diminishing.

This predictability could be exploited.

A burning patch laid across one escape route would funnel a fleeing eboat toward another vessel, or toward shallower water, where its speed advantage diminished, or simply slow its departure long enough for a torpedo to be aimed with greater accuracy.

There are at least seven documented engagements between September 1942 and June 1944 in which the fire weapon directly influenced the tactical outcome of a coastal forces encounter with Germany boats.

Records held at the National Archives in Q, primarily in the ADM 199 series, describe engagements in the Tempame’s estuary off the Dutch coast and in the western approaches to the Sherborg Peninsula.

In two of these actions, eboat commanders filed afteraction reports attributing their withdrawal to the presence of the incendiary weapon rather than to conventional gunfire or torpedo threat.

In one remarkable engagement offend in March 1943, an ebo flotilla of five vessels declined to press home an attack on a convoy they had successfully located and were in an excellent position to strike after the escorting MTB deployed the fire weapon against the lead vessel’s approach vector.

The convoy reached port intact.

For context, it is instructive to consider what the Germans were doing in the same period and what the Americans brought to similar tactical problems.

The Criggs marine had no equivalent weapon in their eboat arsenal.

German fast attack doctrine was built almost entirely around speed, night movement, and the torpedo with light automatic cannon for surface defense.

The concept of deploying incendiary area denial weapons from fast craft was not part of German coastal doctrine and the records of the schnell bootaffer’s tactical development through 1943 and 1944 show no serious attempt to develop a comparable system.

This was partly a matter of industrial priority and partly a reflection of different tactical assumptions.

The Germans expected to be the aggressors and had little interest in weapons that were primarily defensive in psychological terms.

The Americans operating in the Mediterranean and later the Pacific developed their own flame armed PT boats, most notably adapting the army’s standard flamethrower technology for coastal craft use.

The American systems tended toward greater raw fuel capacity and longer burn duration, reflecting American industrial abundance.

However, the British thickened fuel approach, lighter, more reliable under rough North Sea conditions and more readily adaptable to the relatively small British MTBs, was assessed by the US Navy liaison mission in London in January 1944 as technically superior for the specific conditions of channel and North Sea operations.

The American assessment noted in particular the British fuel thickening compound superior performance in cold water and high wind conditions.

Circumstances the Americans encountered far less frequently in their primary theaters of operation.

The concept of using fire weapons from small naval craft was not entirely new.

In 1942, the ancient Bzantine Navy had used Greek fire from galleys, and First World War experiments with petroleum weapons from motor launches had produced mixed results in the Adriatic.

What distinguished the DMWD system was the precision of the fuel chemistry, the reliability of the pressurized delivery mechanism, and crucially, the tactical doctrine that accompanied it.

The weapon did not exist in isolation.

It was accompanied by detailed tactical guidance developed through the coastal forces development unit that specified precisely how, when, and in what circumstances the fire weapon should be deployed to maximum effect.

Other navies that subsequently encountered the concept tended to focus on the engineering.

The British understood that the engineering was only half the innovation.

Assessing the actual historical impact of the short range incendiary weapon is complicated by the limitations of the available record.

German eboat tactical logs, many of which were destroyed or captured in the final weeks of the war, are incomplete, and British afteraction reports sometimes conflate the fire weapons effect with that of other coastal forces armaments.

What the evidence does support is that between 1942 and 1944, the weapon directly influenced at least seven engagements and indirectly altered the tactical calculus of eboat operations in the channel and southern North Sea.

Eboat patrol logs from mid 1943 onward show a measurable tendency to avoid contact with MTB groups that were known or suspected to be carrying the fire weapon.

The psychological deterrent effect may well have exceeded the material effect, which is itself a measure of the weapon’s success.

The weapons influence on later development is subtle but traceable.

Postwar analysis of coastal forces doctrine fed directly into the development of close-range naval weapons for the Cold War era and the principle of using incendiary area denial weapons to channel rather than destroy enemy fastcraft influenced British naval tactical thinking well into the 1950s.

The specific fuel thickening compounds developed for the naval projector system contributed to research that would eventually feed into later generations of British naval firefighting suppression technology.

An ironic legacy for a weapon designed to start fires rather than extinguish them.

Of the approximately 200 original systems manufactured, very few survive in any complete form.

The Imperial War Museum’s collection at Duxford contains components from a partial system recovered from a decommissioned MTB hull in the 1970s, though the complete assembly has never been publicly displayed.

The National Maritime Museum at Greenwich holds technical drawings and procurement documentation.

A single largely complete example minus its fuel tanks is held in storage by the Royal Navy Museum at Portsmouth and has been examined by researchers but not placed on public display.

The wooden vessels themselves, the MTBs and MGBs that carried these weapons through the worst of the coastal war have almost entirely vanished.

A handful of restored examples exist in private hands and at the Dunkirk little ship’s collection, but none of the specific craft known to have carried the fire weapon survives intact.

Return then to the night of 19th October 1942 and to MTB 236, sitting low in the cold water 40 km from the Normandy coast.

The Eboats are out there in the dark, experienced, aggressive, supremely capable predators of the night sea.

They have hunted these waters for 3 years.

They have sunk merchant ships and warships and landing craft.

They have outrun and outlasted almost everything the Royal Navy has sent against them.

And yet tonight, they turn away.

They turn away because of fire.

Because the men aboard MTB236 are carrying a weapon that removes one of the most fundamental assumptions of fastboat warfare, that if things go badly, you can always run.

Fire on the water does not care how fast you are.

Fire on the water does not distinguish between a 39 knot eboat and a stationary vessel.

Fire on the water simply burns.

The short range incendiary weapon did not win the coastal war.

It did not sink the eboat fleet or neutralize the threat they posed to Allied shipping lanes.

The men of the Schnelbwafa continued to fight with skill and courage until the very end of the conflict.

In the channel and North Sea remained dangerous waters for Allied convoys throughout the war.

But the weapon changed something.

It introduced uncertainty into the minds of men who had previously been able to calculate their odds with some confidence.

It removed the guarantee of safe withdrawal.

It made the dark water less predictable.

And unpredictability in warfare, as in most human endeavors, is its own kind of weapon.

Britain in the Second World War produced many weapons of greater fame.

The Spitfire, the Lancaster, the Churchill tank, the submarine.

It produced weapons of greater lethality and wider impact.

But there is something worth remembering about the less celebrated innovations.

The weapons developed in small workshops by clever pragmatic people who understood that the purpose of a weapon is not always to destroy.

Sometimes the purpose of a weapon is simply to make the enemy afraid to make them hesitate.

to make them for one critical moment on a cold October night in the middle of the channel decide that the better part of courage is to turn around and go home.

MTB236’s convoy reached port safely.

The eboats never returned to that patrol area that season and the sea for one night at least burned.

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