Popular Science (January 1966);
"Silent Sea Engine for Nuclear Subs"
Popular Science (January 1966), pp.
113-115; "How to Build Your Own Sea Engine"
Product Engineering (February 24,
1969); "Magnetic Propulsion May Be Ready For Small Subs"
Discover Magazine (May, 1980s); "The
Warren A. Rice, Warren: US Patent #
2,997,013; "Propulsion System"
NY Times (May 18,
2008 ): Experimental Propulsion System Has No Moving Parts
Popular Science (January 1966), pp. 113-115, 188
"Silent Sea Engine for Nuclear Subs"
In the silent world of underwater warfare, the slightest noise
can bring sudden death to a submarine. The electronic eats of
the enemy can detect conventional engines and screw propellers
as far as 100 miles away. A computer interprets the sounds and
directs a deadly homing torpedo to their source in minutes. How
do you go about maneuvering a 3260-ton nuclear submarine without
making a sound? Two medical researchers at St. Louis
University’s School of Medicine may have found the answer --- a
revolutionary undersea propulsion unit dubbed the "sea engine".
The interesting phenomenon upon which the sea engine is based
was first observed in 1964 by Alfred W. Richardson, a
physiologist, and Sujoy K. Guha, a young biomedical engineer
from India. The two men were looking for a method of stimulating
the flow of blood through the human body. They tried various
types of mechanical pumps without success. The pumping action
was too irregular.
While investigating the effects of magnetic fields on weak salt
solutions similar to blood, the two researchers stumbled across
an interesting fact They could make the electrically charged
atoms in such solutions move in one direction by applying a
magnetic field in just the right way. Then they made a second
important discovery: The moving atoms dragged water molecules
along with them so that the entire solution moved.
Richardson and Guha suddenly realized that they had the makings
of a new type of pump. They quickly assembled an experimental
model and found, as they had expected, that the device really
worked. Their "pump" consisted of nothing more than an
unimpressive collection of junk-box electronic components. Yet
the instant they connected it to a source of electrical power, a
weak salt solution inside it began to move. A number of tests
were made and new models were constructed, some of which
permitted very accurate control over the quantity of liquid
being pumped, and others which made the liquid move in a series
of pulses, duplicating the pumping action of the human heart.
Amazingly, the pumps could move a variety of liquids ---
including ordinary tap water --- without difficulty. Then a
visiting scientist from the Office of Naval Research suggested
they try pumping sweater. The pump worked better than ever.
The sea engine is a form of electromagnetic pump, which is
nothing new. Units working on the same principle have been used
to pump liquid metals such as sodium through nuclear reactors
for coolant purposes. However, a pump had never before been
constructed to move seawater --- electronically, with no moving
parts, with no sound. And that’s what intrigues naval engineers.
The Navy Problem ~
Nuclear submarine skippers have had to develop a variety of
ways of escaping detection. At times, they dive to fantastic
depths where sub noises may be confused with other ocean sounds.
Or they may sit quietly on the bottom and wait for the enemy to
come to them. In any case, starting the engine may mean
An electromagnetic pump large enough to propel a submarine
would require a lot of electrical power, but this would present
no power on a nuclear submarine. Naval engineers made a study of
an advanced pump constructed by Richardson and Guha, and found
that conversion from pump to sea engine necessitated only minor
A submarine would be equipped with two sea engines: one to port
and one to starboard. Each engine would operate independently,
the direction andforce4 of its propulsive jet of seawater
changed by the mere flick of a switch. In this way, the sub
could move forward, backward, or turn by pumping water in one
direction on one side and in the other direction on the other
Most likely, sea engines would be installed along with
conventional high-speed screw engines for normal use. The sea
engines enable the sub to engage in silent warfare by gliding
along the ocean bottom and maneuvering close to its prey.
How It Works ~
The simplest form of sea engine consists of two metal-plate
electrodes mounted parallel to each other inside a rectangular
chamber called a "cannula". An opening at each end of the
cannula permits seawater to flow between the electrodes. The
cannula is mounted between the poles of a powerful
electromagnet, so that the magnetic field is concentrated on the
water between them.
When alternating current is applied to the two electrodes,
large numbers of ions --- sodium and chlorine atoms in sweater
--- are immediately attracted to the water between them. These
ions attempt to move back and forth between the electrodes.
Their individual magnetic fields (each ion is surrounded by its
own tiny EM field) are repelled, however, by the powerful
external magnetic field. Many of the ions are thus forced to
move sideways, away from the electrodes. As they move along,
they drag water molecules with them, causing the water to move
out of the cannula. More seawater enters from the other opening,
producing a continuous flow.
Torpedoes & Destroyers ~
There is every reason to believe that a sea engine will power a
radically now type of torpedo. The ones we’re using now produce
a relatively loud sound, giving an alert enemy a chance to duck.
A somewhat slower fish, powered by a silent sea engine using
high-capacity batteries, would change this.
Highly specialized types of surface ships, such as the
hunter-killer destroyers, could also profit from periods of
silent running with sea engines.
How about the pumping of blood --- the application of the EM
pump that Richardson and Guha first set out to explore?
Experiments are currently under way to use a modified sea engine
to temporarily replace the human heart during surgical
operations. Another model may one day by used to pump waste from
a patient’s body during long operations.
Fifteen years ago, a government report said: “"Undersea warfare
is a deadly game of blindman’s bluff, in which the winning side
is likely to be that with the most acute hearing". A footnote
might add, "and the quietest engines".
Popular Science (January 1966), pp. 113-115
"How to Build Your Own Sea Engine"
Switch on the power and watch a stream of slat water
mysteriously begin to flow around and around a closed loop of
plastic tubing. How? Build your own sea engine --- a fascinating
gadget for the amateur scientist or a top-flight science-fair
project. It costs just a few dollars. There are many other
things about it that still puzzle scientists; perhaps you can
make an improvement.
Make an electromagnet from an isolation transformer with a
100-watt rating. Cut through the transformer laminations in two
places with a hacksaw (see drawing below) and remove these
pieces. Next, cut a 5/8" gap (no larger) in the remaining
laminations. Connect primary and secondary windings in series (A
to B in the schematic below). Connect C and D to the AC line.
Quickly test the gap for a magnetic field with a screwdriver
tip. Try connecting A and C together and B and D to the AC line,
and again test the gap. One hookup will give a much stronger
field than the other: that’s the one to use.
Make a cannula out of a length of plastic tubing. It must fit
into the magnet gap. Two copper or stainless steel electrode
plates are mounted inside the cannula. Copper is best, but is
attacked by salt water and eventually it has to be replaced.
Carefully solder wire leads to the electrodes. They leave the
cannula through snug holes sealed with a good cement. Use the
same cement to attach ends to the cannula. The ends have holes
fitted with short lengths of glass tubing. Two tiny holes
drilled through the top of the cannula will allow captured air
to escape, permitting it to fill with water. The holes can later
be sealed to prevent leakage. Run a length of plastic tubing in
a closed loop from one end of the cannula to the other. A
T-connection in the loop will aid in filling.
The Assembly ~
Use stove bolts to hold the transformer laminations together.
Mount it on a base, with some type of supports to keep the
tubing at the level of the cannula. Switch S1 is optional. Do
not use a lower-wattage resistor for R1. Since it will give off
some heat, mount it and R2 (optional) on a heat-sink.
Fill a glass with tap water and let it sit for a day to
eliminate air [or boil it]. Add half a teaspoon of table salt
and stir until dissolved. Carefully fill the cannula and tubing
with the salt water. Work out all the air bubbles.
Check all electrical connections before applying power to the
model. Inspect the cannula for leaks, particularly where the
lead wires and glass tubes pass through the walls, If everything
is okay, plug it into an outlet and throw the switch. Watch tiny
dust particles and other impurities in the water to detect flow.
If there is no visible movement, try adding a tiny drop of ink
to the water as an indicator [or install a flow meter].
Try various resistances for R2. Eliminate it entirely and note
the result. Vary the resistance of R1 and see what happens. With
a little experimentation, you’ll quickly find the best settings
for maximum pumping action. Watch the effect of increased
conductivity (adding more salt) on flow rate.
Parts List ~
R1 --- 20-ohm, 160-watt wire-wound power resistor
R2 --- 100-ohm, 25-watt fixed wire-wound power resistor
S1 --- Single-pole, single-throw switch rated at 6 amps or
T1 --- 115-120 volt AC isolation transformer rated at 100 watts
Misc. --- Small sheet of copper or stainless steel, wire,
solder, transformer mounting brackets, plastic tubing, glass
tubing, sheet plastic for tubing supports, AC power cord,
Figure 1 ~ Arrangement of electromagnet with cannula,
containing electrodes positioned in the 5/8" gap, is shown in
cross-section. In the schematic at right, S1 is the switch, R1
and R2 the power resistors, T1 the electromagnet. Connect the
primary and secondary of T1 together as described for the
strongest magnetic field. Leads A and D and B and C are the end
leads of the primary and secondary windings, respectively. Cut
off or tape any adjustable-voltage taps on T1; these connections
are not used. Be sure to remove the plug from the socket before
making any adjustments.
Product Engineering (February 24, 1969)
"Magnetic Propulsion May Be Ready For
Today, electromagnetic propulsion (EMP) for submarines --- a
propellerless and therefore silent and maintenance-free way to
drive a craft through water --- is getting new attention. A
hypothetical design for a 15-ton sub using this form of
propulsion was presented at the recent SAE meeting in Detroit by
Dr Stewart Way of Westinghouse R&D Center, Pittsburgh.
According to Dr Way, a Russian inventor has already begun to
test a prototype like the on Way suggests, and engineers at the
Israel Institute of Technology, Haifa, indicate an intention of
soon building a similar prototype of their own.
Repulsive Principle ~
Way tested the first prototype, a 10-ft model, more than two
years ago (Prod. Engg., September 12, 1966, p. 39). Since then,
he a others have worked, off and on, to explore the idea. The US
Navy had been keenly interested in the concept from 1958 to 1961
but had found the outlook poor for practical application of the
Latest in superconducting magnet technology may have changed
that outlook, Dr Way believes, by greatly increasing the power
The "solid-state" propulsion principle is as simple as high
school physics. If a wire is placed between the poles of a "U"
magnet and current is passed through the wire, the wire jumps
away from the magnet, in response to Lorentz forces. Make a
submarine the magnet and the surrounding water the wire, and you
have an underwater vessel with a no-moving-parts propulsion
Super Magnets for Super Subs ~
For his 15-ton vessel, about 24 feet long, Dr Way concludes
that two tons of batteries could furnish enough energy to drive
the current through sea water. Reaction with a superconducting
magnet aboard the craft could propel the submarine at about 6
knots. And the 2-man vessel could cruise more than 9 hours at a
time, Way says.
Way’s 10ft earlier prototype weighed 900 lb and had 300 lb of
batteries, which had to be recharged after about 15 min. It had
a conventional rather than superconducting magnet, and its top
speed was only about ½ knot.
The researcher says the advent of the practical superconducting
magnet, which draws no power on board, had vastly increased an
EMP craft’s potential range and speed. He suggests that someday
mammoth EMP cargo submarines with displacements of 1`00,000 tons
may be hauling freight silently through the ocean depths at
speeds up to 25 knots. The energy for generating the current
around these supersubs would come from nuclear power plants.
Right now, EMP may be highly suited to small research
submarines, Dr Way says, and he would like to see a full-scale
prototype developed in this country for practical
Silence of operation would mean research subs could literally
sneak up on fish. Water around them would not be agitated, and
ocean-bottom materials wouldn’t be stirred up. Dr Way estimates
tht overall disturbance of the ocean would be reduced 90%. A
small electromagnetic force would be acting over a large area,
rather than a large physical force acting over a very small
area, as with a propeller.
Other Advantages ~
In addition, an EMP sub would be more maneuverable than a
conventionally propelled craft. At slow forward speeds,
conventional submarines don’t respond well to lateral or yaw
changes of direction. Auxiliary propellers to correct this
deficiency only add to ocean disturbance. An EMP sub could
easily be designed to provide lateral and turning forces as well
as "fine control" of elevation.
Dr Way also suggests it may be possible to reduce hull drag by
using the Lorentz force s on the wter that surrounds the hull,
though he didn’t consider this effect in his design.
Design Considerations ~
To be sure, the designer of a working EMP sub would face some
problems. To begin with, the external magnetic field would
attract metal objects on the ocean floor (treasure hunters might
consider this a boon). Dr Way judges that his 15-ton model would
have to steer clear of iron objects by at least 5 ft, else it
might have to deenergize its superconducting magnet in order to
The crew’s proximity to magnetic fields inside the sub is
another problem. But Dr Way reasons it can be solved by placing
the field coil slightly aft and the crew well forward, with an
iron shield between.
Also, liquid helium would have to be circulated around the
superconducting magnet to maintain it at cryogenic temperature.
But Dr Way thinks an on-board refrigeration plant would not be
necessary; the rate at which the helium would boil off is not
excessive. However, the lost helium would have to be replenished
Discover Magazine (May, 1980s, Date/Author
"The Magnetic Ship"
Anyone who has played with magnets knows it is possible to push
one magnet along by forcing the north or south pole of another
close to the same pole of the first. Such a magnetic shove
wouldn’t be a bad form of propulsion if there were a way to keep
it going. In fact, some Japanese scientists are trying to propel
ships using this principle --- but instead of forcing actual
magnets close to the ones built into their ships, they
continually generate repulsing magnetic fields in the surround
seawater to push vessels along. Yoshiro Saji and his colleagues
at the Kobe University of Mercantile Marine in Kobe, Japan, are
convinced that their method of electromagnetic propulsion has
the potential to provide more efficient, faster way of powering
even large tankers.
Saji begins with a large electromagnet mounted along the ship’s
sides. An electric current from on-board generators is then
passed from one side of the ship to the other through conductive
seawater, creating a magnetic force that pushes against the
ship’s magnet. The seawater is driven backwards, and the ship is
pushed forward, As the ship moves ahead, a current continually
flows through a constant repulsive field to drive it onward, In
a sense the ship is lifting itself by its own bootstraps.
The idea of electromagnetic propulsion was first developed in
the 1950s primarily by Stewart Way, then a consultant for
Westinghouse Electric Corporation. He wanted to use it for
submarines, since at the higher speeds promised by
electromagnetic propulsion it would make them faster than
surface vessels, which are hindered by waves. In 1968 Way
constructed a 10-ft working model of an electromagnetically
propelled submarine using conventional magnets. But a full-scale
version of his test vessel would have required magnets weighing
500,000 tons --- about 80 times the total weight of a Polaris
submarine. Lightweight superconducting magnets could have solved
the weight problem, but at the time they were prohibitively
expensive to operate. Work on electromagnetic propulsion the US
came to a standstill.
Saji’s recent work in Japan followed the development of highly
efficient niobium-titanium superconductors, cooled by liquid
helium to a temperature of -550 F. Armed with these new
materials, his group has built two experimental scale models
that he says prove the feasibility of EM propulsion. The second
and larger model is nearly 12 ft long, weighs 1650 lb, and has a
superconducting magnet with a field 60,000 times stronger than
the Earth’s natural field. Experiments have shown that it can
travel about 1.5 miles per hour.
Extrapolating from his studies, Saji believes that a
full-scale, 10,000-ton submarine tanker can achieve a top speed
of 100 knots, or 115 mph; the fastest submarines, now limited by
water resistance to the screw propeller, cannot exceed 70 knots,
or 81 mph. Today’s surface vessels, because of wave drag, are
much slower. Saji estimates the cost of building the sub would
be comparable to the cost of a conventional tanker of the same
size. And he predicts that the sub’s demand for fuel --- to deed
the onboard generator that powers the electromagnet and the
seawater current --- would be less than the fuel needs of a
Although there are no current plans to put Saji’s studies to
practical use, the principles of EM propulsion have other
Yoshiro SAJI ~ Japan Patent JP 61-188297
US Patent # 2,997,013
(August 22, 1961)
Warren A. Rice
The present invention relates to a propulsion system for
vessels traveling in an ionic media and more particularly
relates to drive systems wherein the outer surface of the vessel
constitutes an electrolytic cell employing the ambient ionic
media as an operating electrolyte. Still more particularly the
present invention relates to a vessel propulsion drive requiring
no moving parts and wherein the thrust is accomplished
electromagnetically to promote laminar fluid flow at the
interphase between vessel and media.
The instant drive or propulsion system is applicable to all
vessels, such as ships, submarines, torpedoes, and the like
traveling in salt water. Insofar as can be experimentally shown
the device also has utility as a space drive system for
imparting thrust to a vessel traveling in an ionic atmosphere,
for example, space.
It has long been known that when an electrical current is
passed through a magnetic field that a thrust is accomplished
which obeys the "left hand rule" and which is of a magnitude
directly proportional to the magnetic field strength and
the current density. Such electrical principles are applied in
electromagnetic pumps for the handling, for example, of liquid
material which is an electrolyte. Such a device is illustrated
in US Patent # 2,786,416 issued to Alan Fenemore (March 26,
Similarly, particle acceleration in vacuum tubes has
demonstrated the concept of thrust obtained by intersecting
lines of magnetic flux with a suitable current flow in an ionic
atmosphere. Reference is made to US Patent # 2,397,891 to Donald
Kerst (Februarry 21, 1950).
However, until the instant invention there was no appreciation
of the application of the known principles to the problem of
propelling a vessel in an electrolyte and space.
It has now been found that the structural members of the vessel
itself can be utilized to generate a thrust of sufficient
magnitude to be useful. It has also been found that the flow
obtained at the interphase between hull and fluid media is
substantially laminar so as to impart an added credit to the
concept of vessel propulsion by material reduction in friction.
Thus, the hull itself generates the force to propel the vessel
and the hull form imparts direct surface thrust in contrast, for
example, to prior art propeller propulsion and its accompanying
Accordingly one of the objects is to provide a propulsion means
integrated into the hull structure of the vessel to be
Still another object is to provide a hull surface capable of
serving as a cell in an ionic media so as to provide desired EM
Other objects include the provision of a highly efficient
propulsion means eliminating the necessity for intricate
mechanical movements extending into the liquid media to require
intricate and expensive seal means. These objects include
obvious design simplification which can result from the adoption
of the presently described propulsion means.
In the drawings:
Figure 1 is a schematic perspective view of a tube across which
is gapped a magnetic flux field and showing an EMF crossing the
gap using, for example, sodium chloride in water as the ionic
media, and indicating the direction of force generated by the
Figure 2 is a perspective schematic view of a tube encasing,
for example, the hull or shell of a projectile, vessel, or the
like where the EMF is generated by the cell established by the
silver hull and the magnesium sleeve and where the magnetic flux
lines are available from permanent magnets used as spacers.
Figure 3 is a schematic view of a device which also utilizes a
cell created by structural portions of the hull separated by
suitable insulating strips and having a permanent magnet
internally oriented so as to establish magnetic flux lines
intersectable by the EMF established by the cell in the
electrolyte to provide a thrust force in the direction
Figure 4 illustrates a hull structure in schematic cross
section indicating a segmentalized external system of alternate
N and S magnetic poles supplied with an EMF from a suitable
generator and being conducted by the electrolyte or ionic media
in which the hull is immersed.
Figure 5 illustrates in schematic perspective a system in
accord with the present invention whereby the hull establishes
an electrolytic cell and the magnetic flux density is obtained
by the use of a generator-served electromagnet.
General Description ~
In electromagnetic phenomena it has long been known that if a
current is passed across a magnetic field a force is set up
which generally is dependent upon the flux D, the distance
between conductors, and the amperage or current. The general
formula may be expressed as:
Thrust in kilograms = (10.2 x 10-8 [flux density (gauss) x d
(centimeters) x I (amperes)]
Conversion to pounds of thrust is accomplished by multiplying
the thrust in kilograms b the rough factor of 2.2.
Experimental work based on this data has generally validated
this above expression and supplementally has shown that the
thrust is a reaction to the movement of the electrolyte through
which the current passes. Viewed in a vacuum the thrust may be
expressed in terms of ionic drive employing beta particle
emission with the bonus obtained by appreciation of mass.
Further, the flow pattern appears "laminar" in nature in
contrast to a type of thrust imparted by a driven propeller, the
latter being characterized as "turbulent". Peculiarly the
laminar flow is substantially independent of hull design, that
is, the hull design becomes considerably less critical assuming
that the entire hull is used as a drive fixture.
In general a magnetic field is established using components of
the vessel as alternate N and S poles. As between these
structurally established poles a magnetic flux is established
through an ionic media, for example, an ionized atmosphere such
as space or an electrolyte such as salt water. An electric
current, also emanating from the structural members of the
vessel passes through the ionic media cutting the magnetic lines
of force. The result is a movement of the electrolyte in
obedience to the "right hand rule". The movement is equivalent
to the force exerted in accord with the foregoing general
formulation and a reaction force thus propels the vessel.
When the above expression is applied in space it can be said
that hull members provide the magnetic field and that hull
members also serve the function of anode and cathode for current
flow in an ionic media. However, in the case of space the
electron flow is established by the system and the particle
emission comprises beta particles which appreciate in mass as
they approach the speed of light. Thus, it is felt that some
correction in value of the total thrust should be applied in the
instance of an application to space versus the situation
existing for propulsion in an electrolyte.
In sopme instances the source of EM force may be cell-derived
in which instance the hull of the craft, or portions thereof
comprise a single cell or a plurality of cells where the latter
is advantageous. Where this cell system is desirable permanent
magnets establish the required magnetic field.
It will be appreciated that an electric generator within the
craft may also supply EM force to the anode and cathode members
of the structure and provide an electromagnet with current for
the establishment of magnetic flux lines of desired magnitude.
Similarly, the scope of the contribution to embrace
combinations of cell, magnet, and mechanically generated source
of EM force wherein the magnetic poles and the cathode and anode
elements comprise a structural adjunct to the vessel hull.
Inasmuch as the current must pass through a magnetic field in an
ionic media, a simple form of the device is annular where the
annulus is immersible in the ionic media.
Specific Description ~
The invention may be better appreciated by reference to the
accompanying drawings. With reference to Figure 1, an annular
form of enclosure or hull 11 is illustrated. Thus, the hull 11
is tubular in character and is immersed in an ionic media 12,
for example salt water or ionic space. Magnets 13 and 4,
comprising elements of the hull 11, establish a magnetic field
15 bridging the gap shown. Insulators 16, space the magnets 13
and 14 from closed contact with each other. An anode 17 and
cathode 18 are positioned between the magnets 13 and 14. The
anodes 17 and cathode 18 are positioned oppositely from each
other. When current 19 is caused to pass across the gap through
the electrolyte 12 intersecting the magnetic lines of force 15,
an electrolyte is caused to move in the direction of the force
arrow F propelling the hull 11 in an opposite sense. The
required EM force is supplied by a cell means or from a
hull-contained source such as a battery or generator.
In Figure 2 the cell supplying the requisite EM force is made
up of hull components. For purposes of illustrations a segment
22 of the hull 21 is made up of silver. An annulus 23 made, for
example, of magnesium spacedly surrounds the silver segment 22.
The space relationship is maintained by magnets 24 leaving gaps
through which electrolyte is permitted to flow. The alternate
opposite positioning of the magnets provides a magnetic field
25. In an electrolyte, current is caused to flow between the
silver and magnesium intersecting the magnetic lines of force
and provides a thrust in the direction of the force arrow F.
It will be understood that a suitable external circuit is
provided as a means of controlling or regulating current flow
within the cell and this circuit is schematically represented by
the bus bar connection 21a. An equivalent reactive force moves
the hull 21 through salt water, for example. While a silver
magnesium cell has been described it will be appreciated that
other combinations of anode and cathode chemical cells are well
known in the art and are intended to be included in the scope of
the present invention. Experimental results in brine has
indicated satisfactory performance with the system as described,
the EMF being directly proportional to the area provided by the
cell plates and the strength of the electrolyte. As the plates
22 and 23 deteriorate they may be replaced.
Referring to Figure 3 the hull 31 is longitudinally provided
with a stripe-like pair of plates 32 and 33 running for a
substantial length of the hull 31. These provide an anode and
cathode for cell operation in an electrolyte. When the plate 32
is silver and the plate 33 is magnesium, for example, a current
is caused to flow as between the plates 23 and 33. Insulating
stripes or plates 34 electrically separate the plates 32 and 33.
A magnet 35 structurally bridges the hull cavity, its poles
coinciding with the insulating stripes or plates 34. In this
form the magnetic lines of force travel peripherally around the
hull 31. As an EMF passes between the plates 32 and 34 they
intersect the magnetic lines of force providing an axial thrust
to the electrolyte as expressed by the force arrow F. The
reactive force moves the vessel. As indicated in Figure 2
regulation of current flow in the resulting cell is accomplished
by an external circuit as illustrated in Figure 3 by the bus bar
The EMF passing between the plates, while illustrated as the
product of a chemical cell may be supplied by a generated EMF
from a generator source not shown within the vessel. Similarly
the magnet 35 may be of the permanent type or may be of
conventional electromagnet construction where the field strength
is established by a winding around a suitable core. In a similar
way the EMF and magnet fields of all the structures described
may be supplied by a source of generated EMF.
Referring to Figure 4 a hollow hull 41 is illustrated wherein a
plurality of alternating N and S magnetic poles 42 and 43
respectively line the periphery of the hull 41, the lines of
force emanating from the magnetic poles providing a peripheral
series of magnetic bridges around the hull 41,immersed, for
example, in an electrolyte. Intermediate each of the magnetic
poles 42 and 43, and completing the schematic annular hull 41
are alternate cathodes 44 and anodes 45. Insulating spacers 46
separate the magnets from conducting the EMF emanating from the
electrodes 44 and 45. When a current is fed as between the
electrodes 44 and 45 the current passes through the electrolyte
media in which hull 41 is immersed and cuts the peripherally
bridged lines of magnetic flux to cause a resultant force in a
direction as indicated by the force arrow. The resultant
reactant force drives the vessel 41. A generator 47 supplies the
requisite EMF, the generator being located, as shown
schematically within the hull of the vessel. As previously
indicated a chemical cell may supply the required EMF and the
magnets may be of the permanent or electromagnet types. In the
vessel 41 as shown in Figure 4 it will be appreciated that the
thrust is intimately related to the interphase between hull 41
and the ambient ionic media. In this design the laminar flow
predominates and studies thus far advanced show maximum thrust
substantially at the interphase and diminishing with radial
Figure 5 shows the hull 51 with a single magnet 52 which is in
effect a core served by the winding 53 powered by the generator
54. Anode 55 and cathode 56 comprise electrode means in suitable
ionic media to self generate an EMF which cuts the magnetic flux
lines moving peripherally about the hull 51. This hull structure
illustrates the use of electromagnetic means in combination with
a suitable generated EMF. Insulation spacers 57 prevent the hull
system from "shorting out" in service. As previously described
it will be appreciated that the members 55 and 56 may comprise a
suitable chemical cell.
In operation, structures as described have demonstrated
unusually excellent propulsion seemingly indicative of minimum
hull "drag" at the interphase between hull and ionic media. The
flow at the interphase seems to obey laminar principles.
Having thus described my invention other modifications will be
immediately apparent to those skilled in the art and such
modifications are intended to be included herein limited only by
the scope of the appended claims.
I claim: [ Claims not included here ]
NOTE: Rice's US Patent # 3,106,058 ("Propulsion System") is
Palma NETO ~ Canada Patent CA2342431 ~
Hoenig ECKHARDT ~ Germany Patent DE4137952 (May
19, 1993) ~ The propulsion system consists of a number of
integrated EM stages that are operated with controlled phasing
to generate a fluttering wave action. The stages are set into a
housing (21) with a flexible foam filling (22) and the
individual drive stages (40, 50, 60, 70) are coupled by rods
(26). Each EM stage provides an angular displacement of some 4
degrees and comprises a stator (41, 51, 61, 71) and coil (42,
52, 62, 72). Use/Advantage: E.g. for submarine. Provides high
For detailed technical analysis, see also:
Friauf, J.: Journal of American Society of Naval Engineers
(Feb. 1961), pp. 139-142; "Electromagnetic Ship Propulsion"
Way, S.: Journal of Hydronautics 2(2):49-57;
"Electromagnetic Propulsion for Cargo Submarines"
New York Times ( May 18, 2008 )
Propulsion System Has No Moving Parts
WILLIAM J. BROAD
( Published: May 15, 1990 )
JAPAN, the United States, and perhaps the
Soviet Union, are racing to perfect a revolutionary type of
propulsion for ships and submarines. It has no moving parts,
is virtually silent and promises great reliability at
relatively low cost.
The basis for the advance is a
tongue-twisting phenomenon known as magnetohydrodynamics, or
MHD, in which magnetic fields are used to move water. There
are no moving parts - no motors, no propellers, no gears and
no drive shaft. Instead, a superconducting magnet, more
efficient and powerful than conventional magnets, exerts a
magnetic force on sea water passing through its core, driving
water out the back and creating forward motion.
The technology is featured in the movie
''The Hunt for Red October,'' based on the book by Tom Clancy
in which an advanced Soviet submarine powered by the process
is hunted by the American and Soviet navies.
In real life, scientists say MHD
propulsion might find both military and civilian uses. It
might economically power commercial ships and cargo
submarines. And it might pave the way for a new generation of
military submarines that are quieter than ever, helping them
''It's provocative in its simplicity,''
said Dr. Michael Petrick, a scientist who directs research on
the idea at the Argonne National Laboratory in Illinois. ''But
there's lots of work that needs to be done to make it
Questions to be answered include both its
technical feasibility and utility. So far, the idea has
undergone no known large-scale trial, although that is about
Early next year, the Japan Foundation for
Shipbuilding Advancement plans to launch a 100-foot-long,
prototype MHD-powered ship that will carry up to 10 people.
The test is a sea trial for commercial operations.
And the Argonne lab is spearheading a
military-sponsored program that centers on a 21-foot-long,
180-ton monster superconducting magnet. Its trials, confined
to the laboratory, are to begin early next year. In a
different project, the Navy is considering sea trials for MHD
''The marriage of an MHD propulsion
system to underwater vehicles is a natural,'' said Dr. Daniel
W. Swallom, who manages the Navy-financed program on the
propulsion system at the Avco Research Laboratory in Everett,
Mass. His program's goal is an open-ocean test with a remotely
The Soviet Union has carried out much
basic research on this form of propulsion, but intelligence
experts are at odds on whether the Russians are applying the
idea to their submarines.
Magnetohydrodynamics involves magnetic
fields (magneto) and fluids (hydro) that conduct electricity
and interact (dynamics). The phenomenon occurs naturally in
the Earth's core, giving rise to the planet's magnetic field.
In MHD propulsion, a pair of electrodes
on either side of the thruster pass an electric current
through sea water. The process does not work effectively with
fresh water because it can carry little current. At a right
angle to the current is the magnetic field generated by the
superconducting magnet. The interaction of the magnetic field
and the current produces a strong force on the water, moving
it through the duct in the center of the magnet. If the
polarity of the current is reversed, so is the direction of
The action is identical to what happens
with an electric motor when its magnetic field crosses a
bundle of copper wires carrying an electric current, causing
it to move and the central shaft of the motor to rotate.
The activity in each case revolves around
charged particles. In the motor, the current-filled wires are
filled with moving electrons, which carry a negative charge,
and are strongly acted upon by the magnetic field. In MHD
propulsion, the electric current flowing through the seawater
causes the formation of charged particles, or ions, which in a
are acted upon by the powerful field of
the superconducting magnet. It propels both the ions and the
The direction of the force is at right
angles to the matrix formed by the current and magnetic field.
This effect, known as the Lorentz force, was first quantified
by the Dutch physicist Hendrik Antoon Lorentz in the late 19th
'The Same Old Story'
This form of propulsion was conceived and
tested in the United States more than two decades ago but
languished until the advent of superconducting magnets. These
can be made very powerful and very efficient because, when
their coils are cooled almost to absolute zero, they lose no
electricity to resistance.
In the late 1980's, Japan became the
first nation to publicly embark on a sizable program meant to
achieve MHD propulsion. ''It's the same old story,'' said Dr.
Petrick at Argonne. ''The idea evolves in this country but
someone else picks it up and runs with it.''
Leading the Japanese work is the
Foundation for Shipbuilding Advancement, a private concern
working with Mitsubishi Heavy Industries, Hitachi Zosen and
Mitsui Engineering and Shipbuilding. The foundation is
believed to have spent about $31 million on the research since
''They've gotten the best people from
industry, government and the universities to work on this
thing,'' said William J. Andahazy, a staffer on the House
Armed Services Committee who was once associated with the
American MHD effort.
The Japanese work focuses on the 100-foot
ship, whose top speed is to be eight knots. It has two MHD
thrusters on two huge fins protruding from the craft's hull,
according to a paper by the foundation. A thruster is made up
of six magnetic modules, each fitted with a sea-water duct
some 10 inches in diameter. One thruster assembly is being
built by Mitsubishi
Heavy Industries, and the other, with a
slightly different configuration, by the Toshiba Corporation.
A $12 Million Magnet
The Japanese ship is simply a technology
test, its small thrusters being relatively inefficient. If the
technique is to work commercially, magnets must become
lighter, larger and more powerful.
The Japanese work has helped increase
American interest in MHD propulsion, although the Defense
Department had been studying it for many years. At Argonne, a
$4 million program seeking potential Navy applications is
under way sponsored by the Pentagon's Defense Advanced
Research Projects Agency.
The centerpiece of the lab's work is a
huge $12 million superconducting magnet originally built for
research on super-efficient generation of electricity from
coal. The program's funds were cut, so the giant magnet was
never used. Argonne is adapting the behemoth to search for
subtle troubles that might complicate the MHD process for
large volumes of water.
The big magnet's water channel, 20 inches
in diameter, will speed 25,000 gallons of water per minute
through a 75-foot closed loop, giving researchers their first
clues about the feasibility of full-scale MHD propulsion. If
no show-stoppers crop up, the next challenge will be
engineering, mainly making heavy superconducting magnets much
lighter and more powerful.
''Because the conductivity of sea water
is so low, you have to go to very large sizes on the thruster,
with big superconducting magnets,'' said Argonne's Dr.
Petrick. ''They have to be lightweight. All that's going to
require almost a breakthrough.'' The problem is that
superconducting magnets are so strong they literally try to
tear themselves apart. Intense magnetic fields cause tiny
movements of internal parts and coils, in turn generating heat
that can trigger the violent loss of superconductivity. To
solve the problem, magnet designers use heavy metal fixtures
For ships and submarines, said Dr.
Petrick, the new generation of super-strong, super-light
composite materials would have to be applied to the making of
superconducting magnets. ''Theoretically, you can exceed the
efficiencies of propellers,'' he said.
An 'Acoustic Signature'
Even at low efficiencies, MHD propulsion
may be attractive to the military because of its relative
silence. Much tracking of enemy submarines centers on
listening for the sounds generated by complex power trains and
MHD propulsion, notes a recent statement
from the Navy's David Taylor Research Center in Annapolis,
Md., ''offers the potential for an extremely quiet system for
propelling underwater vehicles.''
Potential problems from the Navy's point
of view include hydrogen bubbles given off at the system's
electrode from the electrolysis, or breaking into component
parts, of sea water. The bubbles, according to the Taylor
statement, ''have an acoustic signature and may produce a
visible wake.'' Potential solutions, it said, include gasless
electrodes and bubble capture.
Another potential hurdle is a magnetic
''signature,'' or detectable signal. This might be reduced by
special magnet designs or shielding.
Hopeful of solutions, the Navy is now
building a $1.2 million facility in Newport, R.I., to study
the use of superconducting magnets in undersea propulsion.
MHD, said the Taylor statement, ''could provide a
revolutionary new propulsion system for underwater vehicles in
the next century.''
Intelligence experts are divided on where
the Soviets stand in the propulsion field. The Russians have
published many scientific papers on the topic
and have pioneered all kinds of MHD
Some experts say the Soviets have even
been trying it at sea, noting the long pods atop the vertical
rudder of all first-rank Soviets nuclear attack submarines.
However, other experts disparage such analysis, saying the
pods are probably for stowing sensors that can be towed behind
the submarines. Soviet MHD propulsion, they say, can only be
found in fictional
exploits such as ''The Hunt for Red
Magnetohydrodynamics 2004, 2005
This is an electrical propulsion method with no moving parts
which applies to any conductive fluid including water, liquid
metal or plasma. Here I am demonstrating the principle with
water. Essentially two electrodes in water have a current
passed between them in a magnetic field and the water is forced
out the back creating thrust. It is not really a
commercial proposition but was featured in "The Hunt for Red
October" as the Soviet stealth sub.
In my model there are two 1 inch NIB magnets about an inch
apart. At right angles to this are two electrodes which pass
about 1.6 A 9.6 VDC in salt water. ie about 15 watts.
Power is by a model car NiCd pack. The whole decidedly
unseaworthy construction is made of Balsa and is about 8 inches
Performance is underwhelming and I would guess at 1cm/sec boat
Using off board power of 1kW (100V 10A) there is a lot
more action and production of hydrogen and ?oxygen or chlorine
bubbles streaming from the stern, but I don't have a big enough
tub of saltwater to test it for speed. On the right is the
ignition of the hydrogen bubbles with the bright yellow flame
from the sodium in the seawater bubbles. Normally a hydrogen
flame is almost colourless. After a short while the
electrodes wear away and the water fills with debris, presumably
insoluble salts of the metal electrodes.
The 2005 model is now here! Features: 2.5
times the power (16 alkaline AA cells giving 24V - previously
9.6V NiCd pack) Typically 50W output from salt water
swimming pool (20V 2.5A) through to near saturated salt solution
(12V 4.5A.) Vertical twin magnets to avoid compass rotation
effects and now one magnet is within the hull hence reduced
friction. Heavy Aluminium electrodes more completely contained
in the magnetic field. It's red hence should go three times as
Small print. It's still incredibly slow. Handles like a
brick. It's still no use to anyone. Full sea trials yet to be
For the 4HV discussion on MHD and upcoming competition: http://old.4hv.org/index.php?board=4;action=display;threadid=1287;start=0
For more information try this site: http://www.physics.ubc.ca/~outreach/phys420/p420_96/reg/main.htm
I have finally found the description of the Japanese MHD boat,
the "Yamoto" made by Mitsubishi in the 1990's and weighing 185
tons which travelled at 15 km/h. It uses a superconducting 4
Tesla magnet, and the round cross section of the motor looks
remarkably like mine but about 10 times the diameter (260mm).
Electrodes are Titanium with anode coating of DSA (?) and the
cathode plated with Platinum. The length of electrodes is 3.4 m.
Fascinating article with lots of diagrams.
Magnetohydrodynamics and the Lorentz Force
Reg Milley ( U.B.C )
Magnetohydrodynamics is a subject that concerns itself with
several branches of fundamental physics, in particular
electricity and magnetism, and thus makes a good demonstration
for the senior high school years. Magnetohydrodynamics, or MHD
for short, is an application of the Lorentz Force Law which can
be used to propel boats and such in an ionic solution, such as
salty sea water.
This type of propulsion unit is still being considered as an
efficient mode of transportation by some industries of the world
however there are still some major engineering problems to
overcome. For example the average magnetic field strength to
propel a freighter would have to be in the order of 8 to 20
teslas (a fridge magnet, that you would find in your home, is
only about 0.01 tesla!). A way to overcoming this particular
problem is through the use of high temperature superconducting
This presentation will be primarily concerned with the theory
behind the operation of a magnetohydrodynamic propulsion
mechanism that will propel a model boat in a pool of salt water.
The static display and the converted model boat are a relatively
inexpensive way to demonstrate some fundamental theories of
electricity and magnetism. The total cost should not exceed the
200 dollar mark (depending on the resources available to you).
The presentation itself might have some added demonstrations
involving the relationship between electricity and magnetism
(for example to make an electromagnet out of a nail and some
copper wire.), but in general the core presentation is to
explain, at a senior high school level, the concept of
There exists at least one other design for a MHD powered boat
of this nature which might be a good reference for any students
interested in building one for themselves:
Selfpowered Magnetohydrodynamic Motors, by Stanislaw Bednarek.
Found in the American Journal of Physics, Volume 64, No.
1, January 1996.
The basic structure of the MHD mechanism is schematically
represented in Figure 1. The two electrodes and two magnets are
placed in a salt water solution (preferably saturated) so that
the magnetic field is perpendicular to the current flowing
through the water. The ions in the water will be attracted to
their respective electrodes (opposite charges attract) creating
a situation where the Lorentz force law can be applied.
This schematic diagram can be used to find the direction of the
force on the charged sodium and chlorine ions. To do this you
can use the right hand rule directly, however remember that the
right hand rule described here only applies to POSITIVELY
charged particles. To fully understand how to apply the right
hand rule to negatively charged particles you need to go into
the concept of VECTOR CROSS PRODUCTS which is beyond the scope
of this presentation ie: not covered in grade 12 physics.
A better way to figure out the direction of the force is to
construct a set of axes, as shown in fig.1, and use the scalar
equation of the Lorentz force law
To construct the axis you need the right hand rule. The
positive velocity direction is in the direction of conventional
current ie: the direction of the positive charge flow (+ to -).
All the other positive axes follows from the right hand rule
(Thumb in + v direction ...).
Now using F = QvB you ignore the actual numbers of Q, v, B
(since they would be difficult to measure) and work with the
SIGNS of the numbers. In the cases of v and B, the signs
correspond to the respective DIRECTIONS of v and B according to
the axes you just set up. For Q the sign corresponds to whether
the particle is positively charged or negatively charged (in
this case Na+ or Cl-). Thus the sign of the resultant force is
just found by multiplying all the signs together, according to F
= QvB, and the direction is found from the axes you constructed.
For example refer to fig.1 and take Cl- :
# The sign of Q is -
# The sign of v is -
# The sign of B is +
Therefore two negatives and a positive all multiplied together
gives a positive and so the force on the chlorine ion is in the
positive F direction which is out of the page. The same can be
done for the sodium ion and the resultant force is in the same
Right Hand Rule
Lorentz Force Law
The Lorentz Force Law can be used to describe the effects of a
charged particle moving in a constant magnetic field. The
simplest form of this law is given by the scalar equation
F = QvB
# F is the force acting on the particle (vector)
# v is velocity of particle (vector)
# Q is charge of particle (scalar)
B is magnetic field (vector)
NOTE: this case is for v and B perpendicular to each other
otherwise use F = QvB(sin(x)) where x is the angle between v and
B. When v and B are perpendicular x=90 deg. so sin(x)=1.
The right hand rule comes into play here to figure out which
way the force is acting.
Right Hand Rule
For a POSITIVLY charged particle moving (velocity v) in a
magnetic field (field B) the direction of the resultant force
(force F) can be found by:
# 1) THUMB of right hand in direction of VELOCITY, v (first
# 2) INDEX FINGER of r.h. in direction of FIELD, B (second
# 3) Your PALM (or middle finger if you like) now points in the
direction of the FORCE, F (final vector)
The force will ALWAYS be perpendicular to the PLANE of the
vectors v and B, no matter what the angle between v and B is.
Just pretend the following picture is of your right hand:
Calculating the Magnitude of the Force
Once you have found the direction of the force you need to
calculate its MAGNITUDE. You can't directly use the standard
form of the Lorentz force law since the values of Q, v and B
would be very difficult to measure. So you have to convert the
equation in terms of things which are easily measured:
Start with F = QvB
# I = Q / t (definition of current) therefore Q = I t
# v = d / t (definition of velocity)
# substitute to get
F = (I t)(d / t)B simplify...
F = IdB
# I is the current of charges
# d is the distance traveled by the charges
# B is the magnetic field (perpendicular to the direction of the
The boat itself needs a reasonable force to accelerate it. The
following calculations are based on my construction of the boat.
Use F = I d B
I = 3 A (short circuit current between electrodes)
d = 2.7 cm (0.027 m) (distance between electrodes)
B = 0.2 T ( S.I. units: 0.2 N/(A*m) measured)
therefore force on water (force propelling the boat) is:
F = (3.0 A)(0.027 m)(0.2 N/(A*m))
F = 0.0162 Newtons
It is only natural that students in grade 12 physics don't have
an intuitive idea of how much this force actually is, so to put
things into perspective you ask the question:
what mass would this be if the force is due to gravity acting
on that mass?
# F = ma = mg therefore m = F / g
# F = 0.0162 N ; g = 9.8 m/s2
# m = (0.0162 kg*m/s2) / (9.8 m/s2) = 1.6 grams
# is about the mass of a penny.
What acceleration does this produce on the boat?
Boat has mass 0.470 kg
F = ma therefore a = F/m = (0.0162N)/(0.47kg) = 0.04 m/ s2
What speed will the boat be going after 30 s?
a = v/t therefore v = at = (0.04m/s2)(30s) = 0.0012 m/s = 1.2
Not fast but still noticeable!
This section contains pictures and descriptions of the MHD
motor, static display and boat which I used in my presentation.
Firstly, you need to see how many batteries you need to carry
on the boat. By experimentation and calculation it was found
that the force produced by a current of 3A, supplied by a 9 volt
battery, would do nicely. Is 9 volts enough to produce this
current in a saturated salt water solution?
# Use R = d/(A) where d is the distance the current travels
A is the cross sectional area of the material in which the
current is traveling
is the conductivity of the material
In this case the material is a saturated salt water solution
# d = 0.04 m is the distance between the electrodes
# A = 0.0008 m2 is the area of an electrode = 22.6 (m)-1 for
saturated salt water at 20 deg. Celsius
# Carrying the calculation through to get R = 2.21 . Now use
Ohms Law: V = IR where I = 3A (short-circuit current of a 9 volt
battery) V = 6.64 volts So a 9 volt battery should do the job.
If the water is not saturated, which was the case with my
project, you might want to put some more batteries in series. (I
had 3 in series; on the heavy side)