They Doubted His Engine — Until It Powered Every U.S. Submarine in the Pacific !

In 1941, the United States Navy faced a

crisis that most Americans never knew

about. It had nothing to do with

aircraft carriers or battleships. It had

nothing to do with codes or strategy or

diplomacy.

It had everything to do with a problem

buried deep inside a steel tube hundreds

of feet beneath the surface of the

Pacific Ocean. The submarines were

failing and the men inside them were

dying. Not always because of enemy fire,

but because of engines.

The story of how that crisis was solved

does not begin in a naval shipyard. It

does not begin in a laboratory in

Washington or a design office at

Electric Boat in Groton, Connecticut. It

begins in Wisconsin in a factory that

used to make weighing scales.

Fairbanks, Morse & Company was born in

1823 in St. Johnsbury, Vermont.

Thaddeus Fairbanks was an inventor with

a practical mind. He started by making

plows and stoves, but his real

breakthrough came in 1832 when he

patented the platform scale. A simple

lever-based device that could weigh a

loaded wagon without unloading it first.

It sounds ordinary today. In the 19th

century, it was a revolution.

Farmers, merchants, and shippers had

spent generations guessing at the weight

of their goods.

Fairbanks gave them precision.

The scales sold in their thousands, then

their tens of thousands, spreading

across the United States, into South

America, into Europe, and all the way to

Imperial China.

Fairbanks scales won 63 medals in

international competition.

For a time, the company was the most

recognized industrial manufacturer in

the entire United States.

A company employee named Charles Hosmer

Morse opened a branch office in Chicago

and began steering the business in new

directions.

He brought in Leonard Wheeler, a former

missionary from Wisconsin, who had

designed a particularly durable windmill

for pumping water, the Eclipse Windmill.

Wheeler had set up his operation in

Beloit, Wisconsin just after the Civil

War and within a generation half a

million Eclipse Windmills dotted the

American landscape from the Great Plains

to the Australian Outback.

When Morse formalized the partnership,

the firm became Fairbanks, Morse &

Company headquartered in Chicago and

manufacturing from Beloit.

The product catalog grew year by year.

Pumps, tractors, stationary engines,

generators, radios, and eventually

locomotives.

The Beloit factory was not a

single-purpose building.

It was a monument to industrial

flexibility.

But flexibility, it turned out, was

exactly what the United States Navy

would one day desperately need.

To understand why, you have to

understand the challenge facing American

submarines in the Pacific.

When Japan struck Pearl Harbor on

December the 7th, 1941, the United

States had a small but capable submarine

force.

The Navy's strategy immediately shifted.

With the battleship fleet crippled at

Pearl Harbor, with the concept of a

massive set piece gun battle suddenly

obsolete,

the submarine became the instrument of a

different kind of war,

a war of strangulation.

Japan was an island nation. It had no

oil of its own, no iron ore, no rubber.

Every ounce of the raw material that

kept its factories running and its army

fighting had to cross the Pacific on

merchant ships.

Sink those ships and Japan would slowly

strangle.

The plan was sound. The execution was

hampered by one enormous practical

problem. A submarine is not simply a

ship that travels underwater. It is a

diesel-electric machine that must

perform two entirely different tasks. On

the surface, it runs on diesel engines,

large, powerful combustion engines that

drive the propeller shafts and

simultaneously charge vast banks of

batteries.

Underwater, where the diesels cannot

breathe, it runs purely on those

batteries, powering electric motors in

near silence.

The diesel engines, therefore, are the

heart of everything. They are the source

of all stored energy, all offensive

range, all tactical endurance. If the

engines fail, the submarine cannot

charge its batteries. If the batteries

drain, the submarine cannot maneuver

underwater.

If the submarine cannot maneuver

underwater, it cannot survive.

The early Pacific patrols revealed the

problem in brutal fashion. American

fleet boats were conducting patrols of

60 to 75 days across the vast distances

of the Western Pacific, from Pearl

Harbor to the coast of Japan and back.

The Gato-class submarines that would

become the workhorses of this campaign

were designed with exactly this

endurance in mind.

They were large boats, 312 feet long,

equipped with showers, refrigerated food

stores, air conditioning, and bunks for

nearly the entire crew,

luxuries unheard of in the Royal Navy's

boats or the German U-boat fleet.

Admiral Charles Lockwood, commanding the

Pacific submarine force, understood that

if you wanted men to spend 75 days at

sea in a steel tube, uh you had to give

them a reason to function.

But none of that mattered if the engines

failed.

The Navy had relied primarily on Winton

and General Motors diesel engines for

its fleet submarines, along with

Cleveland diesel units.

These were conventional four-stroke

designs, known quantities, broadly

serviceable.

But as the building program accelerated

toward hundreds of submarines, the Navy

needed something more, something more

powerful per unit of volume, something

more compact, something that could fit

into the long, narrow pressure hull of a

fleet submarine without consuming space

desperately needed for torpedoes,

batteries, and crew berthing.

The answer, when it came, arrived from

an unexpected direction, from Germany,

and from a man who had been building

engines since the age of the Kaiser.

Hugo Junkers was a German engineer of

the old school, methodical, brilliant,

and possessed of a particular obsession

with the two-stroke combustion cycle.

He began his experimental work on diesel

engines as early as 1892 at a small

factory in Dessau, Germany.

His central insight was radical.

In a conventional diesel engine, each

cylinder has a single piston that moves

up and down inside a closed bore with a

cylinder head forming a sealed cap at

the top.

Combustion gases, heat, and mechanical

stress concentrate at that head, which

must absorb enormous punishment.

The head is also a source of

inefficiency, dissipating energy that

should be driving the crankshaft.

Junkers proposed eliminating the

cylinder head entirely. Instead of one

piston per cylinder, he used two.

They faced each other from opposite ends

of the same cylinder, moving toward each

other on the compression stroke and

being driven apart by the force of

combustion. There was no head at all.

The combustion chamber formed naturally

in the space between the two piston

crowns at the moment of closest

approach, a space that was pure

combustion with nowhere for heat to

escape except into the pistons

themselves, which could be cooled

through hollow cores.

To manage intake and exhaust without

valves, Junkers used ports cut directly

into the cylinder liner walls.

As the pistons separated, they uncovered

rows of intake and exhaust ports. A

supercharger blower pushed fresh air

through from one side while burned gases

exited from the other.

Because the two crankshafts were timed

so that the exhaust ports opened

slightly before the intake ports,

the system scavenged the cylinder of

spent gases with remarkable efficiency.

The result was an engine with two

crankshafts, one at the top of the

cylinder block and one at the bottom,

geared together to transfer their

combined power to a single output shaft.

It was tall and narrow in cross-section.

It was extraordinarily powerful for its

displacement. It produced almost no

wasted heat from cylinder heads because

there were no cylinder heads. And

because both crankshafts ran at exactly

the forces demanded by the firing

strokes, the engine was nearly perfectly

balanced. No excessive vibration,

smooth, quiet.

By the standards of marine engineering,

it was a revelation.

Junkers developed this concept into an

aircraft engine family known as the Jumo

204 and later the Jumo 205.

These powered early versions of the

Junkers Ju 86 bomber and the Dornier

flying boats that patrolled Germany's

maritime frontiers.

They were efficient, particularly at

altitude, but their power output was

limited compared to the liquid-cooled

gasoline engines that were coming to

dominate military aviation, the

Daimler-Benz 601 that powered the

Messerschmitt Bf 109, or the Rolls-Royce

Merlin that pulled Hurricanes and

Spitfires across the skies of Britain.

Hugo Junkers himself was gone by then.

The Nazi regime had seized his patents

and placed him under house arrest in

1933, and he died in 1935 stripped of

his factories and his work.

The Nazis continued building his engines

without him, but someone else had been

watching.

In the early 1930s,

engineers at Fairbanks, Morse in Beloit

obtained access to the Junkers design

through a licensing arrangement and

studied it with the same methodical

precision that had characterized

everything the company had done since

Thaddeus put his platform scales on the

market a century earlier.

They recognized immediately what Junkers

had understood.

This engine was not suited for aircraft.

Its height and its twin crankshaft

architecture made it awkward where

frontal area was everything.

But in a submarine, those same qualities

became virtues. A submarine hull is

essentially a long, narrow cylinder. The

opposed piston engine was also long and

narrow. Its height, which was a problem

in an aircraft installation, translated

perfectly into the vertical space

available in a submarine's engine room.

Its two crankshafts were simply geared

together at one end and the output taken

from a single shaft.

No wasted volume, no wasted heat,

no cylinder heads to crack or warp under

the stress of depth charge concussion.

By 1934, Fairbanks, Morse had their own

version of the opposed piston engine

running, the Model 38 in an

eight-cylinder variant designated the 38

A 8.

The bore was 8 in, the stroke was 10 in,

and in this configuration the engine

produced 1,200 horsepower at 720

revolutions per minute.

In December of that year, the United

States Navy ordered eight of these

engines,

four each for two Porpoise class

submarines, the USS Plunger and the USS

The relationship between Fairbanks Morse

and the Navy had begun.

Those early engines had problems.

The 38 A 8 design went through revisions

and redesigns through the late 1930s.

By 1938, the engineers in Beloit had

produced a refined variant designated

the 38 D 8 and 1/8, the D indicating the

design generation, the 8 and 1/8 the

bore diameter in inches, fractionally

widened from the original.

It was this engine that would become one

of the most significant pieces of

machinery in the Second World War. The

designation tells you the mechanics at a

glance.

Two crankshafts, upper and lower, no

cylinder heads,

a Roots type supercharger blower driven

by the upper crankshaft feeding

pressurized air into the intake manifold

at the top of the engine,

exhaust ports near the lower end of each

cylinder liner, intake ports near the

upper end,

two pistons per cylinder s- facing each

other connected by long connecting rods

to their respective crankshafts.

12 pistons in a six cylinder variant, 18

in a nine cylinder, 20 in a 10 cylinder.

The Navy's fleet submarines used nine

and 10 cylinder versions as main

propulsion engines.

A smaller auxiliary variant, the 38 E 5

and 1/4, served as backup power.

To install these engines in a submarine

hull, the Navy required one further

adaptation.

In the original design, both upper and

lower pistons could be removed from

their respective ends for maintenance.

But when engineers measured the engine

against the internal dimensions of the

Gato and Balao class hull frames, there

was a problem.

The engine was 4 in too tall to allow

the upper pistons to be serviced in

place.

The engineers at Beloit solved this by

shortening the upper connecting rods by

4 in

and reducing the block height above the

intake manifolds by the same amount.

The compromise was that removing an

upper piston became a more involved

procedure.

The Navy accepted the trade-off because

the alternative was no engine at all,

and the war was not waiting.

What the war was doing from December of

1941 onward was consuming engines at the

rate that no peacetime planning had

anticipated.

As the building program accelerated, 77

Gato class submarines, 120 Balao class

submarines and beyond,

the industrial capacity of existing

suppliers could not keep pace.

The Navy needed more engines, more

reliable engines, engines that could

handle the particular demands of Pacific

warfare.

The Balao class,

which began entering service in 1943,

was the boat that the Fairbanks Morse

engine was built to power.

The Balao was a deeper diving version of

the Gato with a pressure hull plated in

steel of greater yield strength that

pushed the test depth from 300 ft to 400

ft.

This mattered enormously in combat. A

depth charge, the primary anti-submarine

weapon used by Japanese destroyers

throughout the Pacific, detonates at a

specific depth. If the submarine could

dive below that depth, the blast force

dissipated before reaching the hull.

Every additional foot of test depth was

a margin of survivability.

The Fairbanks Morse engine proved

perfectly suited to this combat

environment.

Where conventional four-stroke diesels

were sensitive to the violent pressure

fluctuations caused by nearby depth

charge explosions, the opposed piston

design showed a remarkable resistance to

concussion damage.

Its lack of cylinder heads removed the

most vulnerable component in a

conventional diesel.

By 1943,

the Fairbanks Morse 38 D 8 and 1/8 had

become the standard main propulsion

engine for the Balao class submarine.

A typical Balao carried four main

engines. On the surface at full power,

all four operating together in a

diesel-electric arrangement, the engines

driving generators, the generators

powering electric motors. The boat could

make 17 knots.

This diesel-electric setup meant the

engines never drove the propeller shafts

directly.

The crew could regulate propulsion power

electronically, disconnect a damaged

engine without stopping the boat, and

run individual engines independently for

battery charging while others rested for

maintenance.

That last point mattered more than it

might seem.

In a German Type 7 U-boat running under

Karl Dönitz's Atlantic wolf pack

doctrine, the arrangement was simpler

but less flexible.

In an American fleet submarine running a

Pacific patrol, the ability to take one

engine offline for maintenance while

continuing to operate the others was

often the difference between completing

the patrol and aborting it.

The submarines powered by these engines

were rewriting the history of the

Pacific War in ways the public would not

fully understand until after it ended.

By 1943, with the Balao class entering

the fight in numbers,

the rate of merchants and kings

accelerated.

Japanese losses climbed above 3 million

tons that year.

In 1944, the figures became catastrophic

for Japan.

American submarines were sinking ships

faster than Japanese shipyards could

replace them.

Oil tankers that Japan depended upon to

move petroleum from the captured fields

of Borneo and Sumatra to the home

islands were being hunted down in the

South China Sea and the Luzon Strait.

The USS Flasher eventually claimed the

highest tonnage sunk by any single

American submarine during the entire

war.

Tang, on her patrols of 1944, sank 24

ships before a tragic accident ended her

run.

The Barb fired the only

submarine-launched rocket strike of the

war, hitting a Japanese railway train on

Karafuto Island.

These were the boats and the men that

the Fairbanks Morse engines were

enabling.

Without the reliability of those engines

across weeks of unbroken operations in

enemy waters, without the ability to

charge batteries every night and dive

before dawn, these patrols could not

have been sustained.

The Japanese merchant fleet experienced

this systematically.

The industrial capacity of the Japanese

home islands depended on a continuous

flow of raw materials, iron ore, coking

coal, bauxite, oil, rubber, and food.

As American submarine patrols closed off

one shipping route after another,

Japan's production indices began to

fall. Aluminum smelting dropped because

bauxite convoys were sunk. Steel output

dropped because iron ore convoys were

sunk.

Aircraft production dropped because both

dropped.

And perhaps most critically, oil stopped

flowing.

The Imperial Japanese Navy was

eventually forced to base its major

fleet units near the Borneo oil fields

rather than in home waters

because it could no longer guarantee

that oil tankers would survive the

voyage north.

Submarines had accomplished what no

surface force or air campaign alone

could have achieved.

After the war ended, Japanese military

and civilian leaders acknowledged this

explicitly.

They stated that the destruction of

their merchant shipping had been the

greatest single cause of Japan's defeat,

greater than the firebombing campaigns,

greater than the island-hopping advances

of MacArthur and Nimitz, greater than

the individual fleet engagements at

Leyte Gulf or the Philippine Sea.

The combined Gato, Balao, and Tench

classes destroyed 30% of the Imperial

Japanese Navy and 54% of all Japanese

merchant shipping.

The submarines had won the Pacific War

quietly, without ceremony, running on

diesel engines that nobody in the

civilian world had ever heard of,

built in a factory in Wisconsin that

used to make weighing scales.

The end of the war did not end the story

of the Fairbanks Morse engine.

As the United States demobilized and the

submarine force shrank from its wartime

peak, the 38 D 8 and 1/8 remained the

standard diesel for American

diesel-electric submarines through the

1950s.

When the Navy introduced the Tang class

submarines in the early part of that

decade with a new type of engine called

the pancake diesel, a radical flat

format design intended to save space,

the results were disappointing.

The pancake engines were innovative but

unreliable.

The Navy's solution was straightforward.

Remove them and install the wartime

Fairbanks Morse design that everyone

already knew.

The replacement was so complete that the

engine remained standard for American

diesel-powered submarines through the

early 1960s.

Then came the nuclear age. Hyman

Rickover's nuclear propulsion program,

which produced the USS Nautilus in 1955,

and fundamentally transformed how navies

thought about underwater warfare, made

the diesel-electric submarine largely

obsolete as a front-line combatant.

The Los Angeles class attack submarines,

the Seawolf class, and the Ohio class

ballistic missile submarines that formed

the backbone of America's nuclear

deterrent did not need diesel engines

for propulsion.

They ran on reactor heat, on steam

turbines, on electricity generated

without ever surfacing or burning a drop

of fuel.

But they needed diesel engines anyway

because a nuclear submarine cannot

afford to have its electrical systems

fail entirely.

If the reactor shuts down due to a

malfunction, an event submariners call a

scram, the crew needs emergency power

immediately.

Power to run the pumps that cool the

reactor,

power to maintain fire control, power

simply to survive.

The engineers who designed the first

generation of nuclear submarines

specified diesel generators as emergency

backup power, and they specified engines

they already knew and trusted.

A modified version of the 38 D 8 and 1/8

designated the 38 ND 8 and 1/8 became

the standard emergency diesel generator.

The same engine that powered Balao class

submarines hunting Japanese convoys in

1944 was sitting quietly in the engine

rooms of nuclear submarines throughout

the Cold War, waiting to be called upon.

That is not a coincidence. That is a

testament to the fundamental correctness

of the original design.

An opposed piston engine with no

cylinder heads, two crankshafts, and

ports cut directly into the cylinder

liner has fewer components than a

conventional engine of comparable power.

Fewer components means fewer points of

failure.

Fewer points of failure means the engine

either works or it does not.

And in the decades between 1938 and the

end of the Cold War, it overwhelmingly

worked.

The company's own specifications

eventually noted that the emergency

diesels were designed to start, build to

full power,

and come online in less than 10 seconds.

In an emergency aboard a nuclear

submarine, 10 seconds is the difference

between a manageable situation and a

catastrophe.

At the Beloit facility, production never

stopped. Through the Cold War, through

the various restructurings and corporate

reorganizations that split the old

Fairbanks-Morse Company into its

constituent businesses, the scales going

one way, the pumps going another, the

engine business eventually becoming

Fairbanks-Morse Defense, the engine kept

being built.

Not in the wartime volumes of a thousand

boats to be equipped, but in the steady

quantities that Navy and being requires.

Replacement assemblies, new

installations, updates to fuel injection

systems, dual fuel variants that could

operate on both diesel and natural gas,

finding their way into hospitals, uh

power plants, municipal water

facilities, and flood control pump

stations.

The wartime engines themselves, the ones

that powered USS Pampanito and USS Torsk

and USS Ling and USS Blueback and dozens

of their sister boats are now museum

pieces.

Visitors who walk through the engine

room of the Pampanito preserved in San

Francisco can see them. Massive, tall,

narrow machines occupying the space

between the keel and the pressure hull

overhead.

Their cylinder blocks smooth and gray,

the two crankshaft covers running the

length of each engine like paired

spines.

They are not the aerodynamic elegance of

a Spitfire's Merlin or the cunning of a

Caldwell variable pitch propeller hub.

They are blunt industrial objects,

enormously heavy, designed not to be

graceful, but to be dependable.

Dependable in the engine room of a

submarine under depth charge attack.

Dependable on the surface at night in

the Luzon Strait with Japanese

destroyers on the radar screen and the

batteries needing 20 more minutes to

reach full charge.

Dependable after 63 days at sea when the

oil is dirty and the crew is exhausted,

and there are still a thousand miles of

open ocean between them and home.

That kind of dependability is not

glamorous. It does not appear in metal

citations. It does not get photographed

by newsreel cameras. But in war, it is

the difference between a weapon and a

liability.

Hugo Junkers imagined the architecture

in Dessau.

Fairbanks-Morse translated it into iron

and steel in Beloit and made it

manufacturable.

The women of Wisconsin built them, one

engine every day, while the men were

overseas.

And the submariners of the Pacific took

them to the bottom of the sea, ran them

for 75 days at a stretch, and brought

Japan's empire of ocean to a grinding

halt.

The engine that everyone doubted, too

unusual, too German, too different from

what the Navy already knew,

powered nearly every American submarine

that mattered in the most consequential

naval campaign in modern history, and it

is still being built today in the same

city in Wisconsin by the descendants of

the company that used to make weighing

scales.