IMPROVEMENTS IN APPARATUS TO BE USED IN TORPEDO OPERATIONS, AND IN SEARCHING FOR PROVISIONAL SPECIFICATION
Year: 1881

page_text: LETTERS PATENT to Charles Ambrose McEvoy, of 18, Adam Street, Adelphi,
in the County of Middlesex, for an Invention of "IMPROVEMENTS IN
APPARATUS TO BE USED IN TORPEDO OPERATIONS, AND IN SEARCHING FOR
PROVISIONAL SPECIFICATION left by the said Charles Ambrose McEvoy
at the Office of the Commissioners of Patents on the 16th December 1881.
CHARLES AMBROSE MCEVOY of 18 Adam Street Adelphi in the County of
Middlesex. "IMPROVEMENTS IN APPARATUS TO BE USED IN TORPEDO OPERATIONS
AND IN SEARCHING FOR SUBMERGED BODIES AND FOR LIKE PURPOSES."
This Invention has for its object improvements in apparatus for searching for
submerged torpedoes and other submerged bodies and for indicating the approach
of ships to torpedoes and for like purposes.
The apparatus which I employ in searching for torpedoes is carried by a boat
partly within the boat and partly suspended in the water. Within the boat there
is a galvanic battery and an automatic contact breaker which opens and closes the
battery circuit at short intervals. The battery circuit includes two primary coils
one within the boat, the other outside and immersed some depth in the water being
suspended from the boat by a cable of suitable length in which conducting wires
are enclosed.
Each primary coil has its secondary coil and the two secondary coils are
connected by wires in the suspending cable. Within the boat a telephone is
included in the circuit. The apparatus is adjusted so that under ordinary circum-
stances little or no sound is heard in the telephone notwithstanding the pulsations
of the primary current because the induction in one secondary coil is by adjust-
ment made to neutralize the induction in the other secondary coil. But when a
metallic torpedo or other mass of metal is approached the adjustment is deranged
and sounds become audible in the telephone.
I make use of a like arrangement to indicate the approach of iron ships to
anchored torpedoes; in this case the induction produced near the torpedo is
neutralized by another induction on shore the torpedo and the shore station being
connected by a cable.
The approach of a mass of metal such as an ironclad to the torpedo disturbs the
balance and sounds become audible in the telephone. The torpedo may then bo
fired electrically by means of the cable connection.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Ambrose McEvoy in the Great Seal. Patent Office on the
16th June 1882.
CHARLES AMBROSE MCEVOY of 18 Adam Street Adelphi in the County of
Middlesex. "IMPROVEMENTS IN APPARATUS TO BE USED IN TORPEDO OPERATIONS
AND IN SEARCHING FOR SUBMERGED BODIES AND FOR LIKE PURPOSES."
This Invention has for its object improvements in apparatus to be used in
torpedo operations and in searching for submerged bodies and for like purposes.
My searching apparatus consists of a box or case to be sunk in the water; it
contains two bobbins on which silk covered wire is wound and a cord is attached
to the box or case by which it can be drawn along the bottom of the sea or held
suspended at the depth at which it is desired to search. There are insulated wires
in the cord connecting the wire on the bobbins with other apparatus at the surface
usually in a boat which conveys the searching party from place to place. The
apparatus at the surface comprises a suitable source yielding intermitting or
alternating currents of electricity and two other bobbins similar to those in the
sunken box or case. The wire on one of the bobbins of each pair constitutes a
-primary-coil-in-which-tho-intermitting-or-alternating-currents pass.and that_on_the_
other a secondary coil and in this alternating currents are produced by induction.
A primary circuit may be traced from the source through one primary coil, then by
one of the wires in the cord or cable through the other primary coil and back by
another wire in the cord or cable to the source. A secondary circuit may also be
traced from a receiving telephone with which the observer is provided through one
of the secondary coils then by a wire in the cord or cable to the other secondary
coil and through this by the cable to the telephone.
Thus there are four insulated wires in the cable-two in the primary circuit and
two in the secondary circuit. The two bobbins in the submerged box or case are
simply placed side by side and connected up with the cord or cable. The box
being closed it is placed for a time in melted paraffin in order that all the interstices
may be filled to the exclusion of water.
The box or case may be of any nonmetallic impervious material. The bobbins on
which the upper coils are wound are so mounted that their distance apart may be
readily adjusted.
As the source of electricity a small medical magneto electric machine is very
suitable or a battery of a few cells may be used and the current rendered rapidly
intermittent by a vibrating spring as in an electric bell or by a clockwork
contact interrupter. The annexed Drawing illustrates my Invention; the upper
part Figure 1 indicates the apparatus which remains above water; the lower part
Figure 2 shows that which is submerged. a and a¹ are the parts concerned in the
production of the intermitting or alternating currents; the Drawing indicates
battery cells and a clockwork interrupter, but as already stated a small magneto
electric machine may very conveniently be employed. bis the upper primary
bobbin. c is the lower or submerged primary bobbin. dare the wires connecting
these parts and completing with them the primary circuit. c is the receiving
telephone, the upper secondary bobbin, the lower or submerged secondary
bobbin, h the wires connecting these parts and completing with them the secondary
circuit. The wires d and pass through the cord or cable connected with the
submerged box or case this cord or cable is marked N. The submerged box or
case in which the bobbins c and g are contained is marked O.
The apparatus is used in the following manner. If the search be for a metallic
cable or body lying at the bottom of the sea the box or case Figure 2 is lowered

page_text: until it lies on the bottom and currents from the source are caused to flow in the
primary circuit. Then the distance between the bobbins b and fis adjusted until
little or no sound is heard in the telephone the induction taking place in the
bobbin f being neutralised by that in the bobbin g. The boat then rows slowly
along drawing the box or case along the bottom. When any metallic body is
passed over by it or is closely approached the balance of the induction is disturbed
and loud sounds are heard in the telephone.
The apparatus may be used to indicate the proximity of ships, the box or case O
being attached to a subinerged buoy.
What I claim is the submerged box or case O containing the two bobbins c and
g and the cord or cable N containing circuit wires d and h passing from the said
box or case to above the water, such apparatus to be used in connection with a
source of intermitting or alternating electric currents, with other bobbins b and
fand with a telephone e substantially as described.
In witness whereof I the said Charles Ambrose McEvoy have hereunto set
my hand and seal this Fifteeenth day of June in the year of our Lord
One thousand eight hundred and eighty two.
MCEVOY
C. A. MCEVOY. (L.S.)