There has been some dispute over the placement and appearance of the Lord Kelvin’s motorized sounding machine as was fitted on the Olympic, Titanic and possibly the Britannic.  This offering is intended to satisfy the curiosity of the “dead to the last detail” Rivet Counter.  In this case, I will finally unravel this mechanical wonder as well as verify where it was located on the beloved sisters.
  Credit should be given to my friend Alastair Arnott, Curator of the Southampton Cultural Services, who worked to locate the records needed for this article.  It was because of Alastair’s kind offering to Robert Hahn and myself to view their warehouse in Southampton, thus seeing a few examples of actual Lord Kelvin’s motorized, and hand operated sounding machines, that this writing is possible.
  Alastair was able to locate a retired engineer and Kelvin historian in Essex England.  Though I do not have the historian's name, he did state through Alastair, that the original name of the company was Kelvin and James White LTD., located out of Glasgow.  It was not until W.W.II that the company merged and became known as Kelvin Bottomly and Baird.  After 1947, the name seen on the dials of the sounding machines would change to Kelvin Hughs, as owners changed hands once again.  The term “KELVITE” was given to the sounding machines only after the Kelvin Bottomly and Baird partnership was born.
  The Lord Kelvin’s Motorized Sounding Machine used during the Titanic era was actually a product that was available through the Kelvin and James White catalog in 1907, an upgrade from the old hand cranked Mark IV design (Figure A).

For the purposes of space and time, I will transcribe sections of the actual 1907 instruction manual for you all to read.  Figure B is a picture of a similar type of Kelvin’s that was very close to that seen on the Titanic and Olympic. The device seen here was built after W.W.II, as the name "Kelvin & Hughs LTD." appears on the dial.

All of you modelers anxious to add your sounding machines to your model, or change your old variations, must remember one thing; these devices were covered with a wooden box, putting them well out of view from the outside unless they were in use.
 

  The sounding machines were mounted on the boat deck, port and starboard, just aft and inboard of the forward emergency cutters.  The sounding spars seen on the outside of the boat deck bulwarks were part of this device (figure C), and carried the sounding line from the machine to the water.

Figure D shows the Kelvin’s Sounding Machine on the Olympic during the time of her maiden voyage, covered with canvas.  Figure E shows the same area of the Olympic’s deck right after the Titanic disaster in Southampton.  It must be stated that I do hold a picture that confirms this wooden box’s placement on the Titanic, but it is not available for this article.

 Presented for the first time in an effort to solve the mysteries of the Titanic, are pertinent transcriptions from the instructions for use of Lord Kelvin’s Motorized Sounding Machine from 1907:

  This machine is practically Lord Kelvin’s Mark IV Machine, motor driven.  All the provisions to maintain the constant egress of the wire, for a given speed of the ship, are maintained as before, and the wire runs out under the same conditions.
  The wire drum, and its lignum vitae center bearing, are identical with those in the Mark IV.  As in that machine, on the left side of the wire drum there is a beechwood cheek keyed firmly to the spindle; and, on the right side of the drum, there is a moveable beechwood cheek fixed to the ratchet wheel (which replaces the sprocket wheel of the Mark IV); both ratchet wheel and cheek revolving on a worm thread on the spindle.  The “V” groove for the automatic brake is on the left side of the wire drum; its cord, weights, and tubes, are actually similar to those in the Mark IV machine.  The dial is illuminated for night use by an electric lamp fitted to the top of machine on the side opposite to the skeleton hand wheel.  It is arranged so that only part of the dial immediately adjacent to a pointer fixed to the lamp case is illuminated.
 The motor is in a metal case, fixed on the base of the machine below the wire drum, and inside the framework of the machine.  It is constructed for 100 volts but will work efficiently at 80.  The motor shaft passes vertically through the top of the case, and a small bevel wheel is keyed to it.
A watertight box is fastened on the front of the machine, low down, containing the resistances and the motor switch, etc.  The handle of the switch is fitted with a spring, which is extended when the switch is put to “on”.  If the handle is let go it flies to “off” and the motor stops.
The action of the machine is as follows: -

  To take soundings, the spar is got into position, and the wire snatched in the block of the carrier, and the sinker got over the side, the wire being eased or checked by attending to the skeleton wheel, turning it in the direction to ease, the wire.  The sinker being at the surface of the water, the pointer is set to zero, and the operator puts the loop of the feeler pin over his wrist.
  To “let go” he holds the skeleton wheel with both hands, and gives it ONE TURN in the direction contrary to that of heaving in (one spoke is painted which enables the exact amount for a complete turn to be easily seen), and the wire runs out: he immediately takes his hand off the wheel, and puts the feeler pin on the wire and presses gently, catching the handle of the switch in the left hand.  As soon as the wire slacks, the motor switch is pushed right over, to heave in at full speed.
  The motor starts and moves the bevel wheels; the large one being keyed to the spindle turns it, and the screw thread on the spindle runs the ratchet wheel and its beechwood cheek to the left against the wire drum, pressing it against the left cheek, which is keyed to the spindle.  Everything on the spindle is thus made solid with it, and turns together in the direction of heaving in.  The wire is guided on the drum evenly by a man with a pad of oiled canvas.
When the pointer shows 10 fathoms, the motor switch is eased back gradually, and then stopped before the swivel reaches the carrier block.
  The brake is put on by starting the motor against the resistance of the wire; and it is quite effectual if the motor is started quickly.  When the motor is stopped, and it is desired to work the brake by other means, the skeleton wheel should be given a very quick turn in the heaving in direction.
  As to the additional parts in the motor-driven machine, the bearings of the motor shaft can be oiled through an oil hole on the top of the motor case, and through another near the bottom of the motor case on the left side.  To take up backlash in the bevel wheels, and in order to be able, withdraw the motor out of gear, so that the machine can be used as a hand machine, if necessary, the motor case is fastened to the framework of the machine by screws with elongated holes, and these admit of its being moved sufficiently for this purpose.
To take soundings from forward- the machine should be fixed on the spar deck in the vicinity of the fore bridge so that the working of the machine is under the general supervision of the officers on the bridge.  If space admits, it may be placed on the bridge itself, and this is advisable especially if the spar deck is low and liable to be swept by the sea.
  The wire is kept clear of the ship’s side by a spar, which should be from 30 to 40 feet long according to the size of the ship.  In a long ship a long spar is desirable, in order to keep the sounding wire clear of the propellers during moderate alterations of course.
The spar should not be over 5 ½ ins. In diameter, and should taper slightly to both ends.
The heel is fitted with a gooseneck and clamp to an awning stanchion, or bridge stanchion, or with a swivel bolt to the ship’s rail.  For convenience in shipping and unshipping, the heel fitting must admit of its being guyed forward or aft, and also of its being topped up or lowered down.
The other end of the spar should be fitted with a band and three lugs.  A topping, lift to support the spar in a horizontal position, is secured to the lug at the upper part of the band, and a fore guy and after guy to lugs on the fore side and after side of the band.   When in use the spar is held in a horizontal position at right angles to the fore and aft line of the ship by the topping lift guys. If possible the heel of the spar should be secured at such a height above the deck as to be three of four inches above the top of the wire drum of the machine.

The position of the machine should admit of the men having good footing, and should be in view of the bridge.  It need not necessarily be out close to the ship’s side.  Sometimes it can be placed nearly amidships, and a deckhouse or bulkhead immediately forward of it will afford shelter to the men and the machine from the weather.  The machine should be placed so that the spindle of the wire drum is at right angles to the longitudinal axis of the spar. (Figure F)
When the machine is not in use, and is covered with its canvas cover, heavy gear is liable to be inadvertently placed on it, and signalmen will persist in standing on top of it to make semaphores, injuring the dial and pointer; a box of strong hard wood should be made to fit right over the machine to preserve it.