The U. S. S. Chester and the U. S. S. Des Moines are the only two ships of our navy which are equipped with the Cutler Hamtner system of electric steering. The U. S. S. Montgomery has an electric steering installation, but the principles of its construction differ so radically from the above-mentioned gear that no attempt will be made to describe it. Until very recently the U. S. S. Des Moines was equipped with steam as an auxiliary means of steering, but at the present time she is depending on the electric gear entirely as is also the Chester. This fact, in addition to the successful results obtained from the gear, would seem to indicate that we may reasonably expect to see such installations appear in our future ships, just as we have seen the gradual development of electric turret gear culminate in its present state of perfection.
One undoubtedly has a queer sensation upon taking the deck of a "wheelless" ship for the first time. My first experience with this electric gear occurred four hours after I had joined the ship and while I was standing my first watch on her, and in order that those who follow may not have as startling an introduction as I had, the following remarks are set down. No attempt has been made to enter into the intricate details of the mechanism, on the contrary the work is quite rough and is intended simply to give the uninitiated an idea of what is meant by electric steering gear. It is far from unreasonable to suppose that within a very few years this gear will be as universal as the electric turret gears, which we see on all sides, and that officers of the service, one and all, will have to familiarize themselves with its construction and operation. The features embodied in this gear are so essentially different from the steam steering gear, commonly employed on naval vessels, and the results produced are of such a satisfactory nature, that aside from all else it merits a little consideration.
This electric gear was installed on the Des Moines a little over two years ago, and was put on the Chester at the Boston Navy Yard during the months of February and March of 1912. The two other sets, which were purchased with the intention of installing them on the Salem and the Birmingham, have not been put in as yet, owing to the fact that the opportunity has not presented itself. It is understood, however, that other, and similar, installations are now being installed. Having joined the Chester a short time after her installation was completed, the writer has been, therefore, shipmate with this gear practically since its installation, and has had full opportunity to observe its operation and the general results obtained therefrom., Serving on the Des Moines at the present time, with the same gear, has given me further chance to observe the results obtained and the general behavior of the gear. Before taking up a description of the gear as installed, and of the general results produced, a brief history of the conditions which led up to the installation of this gear on the Chester, as the sole means of steering by power, may possibly be of interest. "
Several years ago the Navy Department became interested in the question of steering its ships by electricity, owing to the possibilities which such an equipment presented of a reduction in weights and space, of the elimination of heat and moisture from the after part of the vessel, of the doing away with the tiller ropes or other mechanical means of operating the steering gear from the bridge, and of the saving of steam which such an installation would effect. This question remained under discussion for a number of years, until about 1909, when a contract was let for supplying an electric steering gear for the Des Moines as an auxiliary to the steam engine outfit. I am under the impression that the question of electric steering is an old one; just how old, however, I cannot say. This contract was placed with the Cutler Hammer Mfg. Co., of Milwaukee, Wis., who advocated the use of an electric motor taking its power directly from the dynamo mains and operated by a powerful automatic controller, thus eliminating the necessity of a motor generator outfit. This contract required the control of the motor to be similar to that of the steam engine; that is, the follow-up system had to be employed (requiring the rudder to move to and to stop at any angle at which the wheel may be placed); and to accomplish this result a small follow-up drum controller was provided in the steering engine room, which was operated by the ship's tiller ropes from the wheel on the bridge.
The preliminary trials of the arrangement of the gear were quite satisfactory. Such changes, however, were made as to install a small reversing switch stand for the electrical control of the gear from the bridge, without the follow-up system, but which would eliminate the necessity for tiller ropes or telemotor connections and utilize only four small wires between the steering engine room and the steering stand on the bridge. It seems that the use of the steam gear, as well as the use of the follow-up control of the electric gear, was thereafter abandoned on the Des Moines, and that steering by the non-follow-up electric system became the fashion.
Although the reports from the Des Moines were of a satisfactory and pleasing nature, the Navy Department was still naturally doubtful about the use of such electric steering-gear equipments, especially as regards the elimination of the follow-up Principle, which long usage had led the service to believe was essential to the satisfactory control of the rudder. It was decided, however, to install such an installation as this on the Chester, to be Operated only by the non-follow-up system, and to remove the steam gear entirely, in order that confirming opinions might be Obtained as to the practicability of abandoning the time-honored follow-up control and of steering naval vessels by electricity. Contract was therefore placed with the American Engineering Co., of Philadelphia, representing the Cutler Hammer Co., designers and manufacturers of this gear, for the Chester's equipment, and as stated above the installation was completed the early part of 1912, about two and one-half years after the first installation had been made on the Des Moines.
As soon as the vessel was ready to put to sea after the installation had been completed, she was ordered to meet the Carpathia at the time of the Titanic disaster, and was engaged in this Mission about a week during the initial trial of the electric gear, Upon which she had to rely entirely for steering from the bridge. Shortly after the completion of this duty, she was ordered to the ice-fields to report the presence of ice-bergs, and was engaged in this work for several weeks. Up to the time, therefore, that the Chester was recently placed in reserve at the Philadelphia yard, she was in practically continuous service from the time the gear was put in, which service was of such a nature as to severely test the operation and reliability of the gear.
The result of all these trials showed this steering-gear device to be satisfactory, and an improvement on the old steam gear as regards accuracy of steering and the ease of operation for the helmsman, and as regards vibration of the ship, and the reduction of heat and moisture in that part of the ship adjacent to the steering- gear compartments. An appreciable saving in the total steam consumption was also noticeable. It is surprising to note with what accuracy and with what small motion of the ship it is possible to steer, the response to the movement, of the master switch stand being very rapid, and the helmsman consequently being able to keep the ship on her course with small helm angles and with no effort whatsoever. It is my opinion that the master switch or non-follow-up control is an entirely practical and suitable arrangement and the helmsmen all preferred this control, with its easy operation and with the quick response of the rudder, to the old wheel control.
It is, of course, the most natural thing in the world for an old hand to throw his wheel to port upon receiving an order to "starboard your helm." We may not always have these old hands with us, however, and one of the natural advantages of this type of gear is that, to starboard the helm, all one has to do is to throw the lever to starboard and watch the helm indicator—the most logical thing in the world.
An analysis of the conditions and of the electrical apparatus supplied indicated clearly that these results would naturally follow, as compared with the steam steering-gear equipment. A cut is shown of the electric steering stand as installed on the bridge; and as its operating lever has only to rotate a small cylinder, containing several contact segments, its ease of operation to the helmsman is at once apparent. The pressure of the thumb and forefinger is quite sufficient to give the ship hard over helm at full speed. From this steering stand small electric wires lead directly to the main controller in the steering engine room, and therefore no lost motion of mechanical parts is involved as in the case of the ordinary tiller rope or telemotor control. This absence of lost motion and the natural rapidity with which electrical apparatus can be operated make the response of the rudder to the movement of the steering stand practically instantaneous. The motor driving the rudder is provided with special winding to give variable speed and torque characteristics, so that the movement of the rudder over the center angles, where the load is light, is exceedingly rapid. These angles are the angles which are usually made use of in steering a ship. From exhaustive tests of the gear on the Chester, it has been found that the time required to put the helm from hard over to hard over is about twenty seconds at speeds varying from six to eighteen knots. The speed With which the rudder is operated over the small central angles, which may be considered as cruising helm angles, is not in direct proportion to this time interval, however, owing to the fact that the electric gear starts immediately and its speed is governed to a great extent by the load produced by the rudder. Hence, in estimating twenty seconds as an interval from hard over to hard over, the actual rapidity of movement over the smaller angles is not brought out. Whether or not the response obtained from the electric gear is more rapid than that obtained from the steam gear, I cannot say definitely, but I rather imagine that it is. At any rate it is more uniform than that of the steam gear.
With the steam engine gear, even when the rudder is standing still, some steam is always passing through the engine valves, causing a waste of steam in addition to that consumed in the operation of the engine which is, to say the least, of low efficiency. Again, the loss occasioned in the condensation throughout a long lead of steam pipe, and the loss due to the steam traps, as well as to leaky valves, etc., are eliminated with this electric gear. In comparing the size of the hole through a water-tight bulkhead which is necessary for a steam lead with that which is necessary for a small electric wire lead, the steam gear must suffer. Again, owing to their small size, several auxiliary electric leads could be run to the bridge, whereas it is obviously out of the question to think of running several auxiliary steam pipes. Beyond a doubt such steam Conditions produce a large degree of heat and moisture in the after part of the ship, and the pipes certainly offer more of a target to the enemy's fire than do a few small electric wires. That there is less chance of a rupture to the electric wiring than there is to the steam line is apparent. Even should such rupture occur with the electric wiring it could be repaired much quicker than could the steam line. From the standpoint of safety to the personnel, it would seem as though the electric connections offer less chances for casualties than does the steam line. To illustrate more clearly the point which I wish to bring out, it is perfectly possible and feasible to run the electric connections from the bridge to the steering engine room down the armored tube and through the double bottoms. This, however, is a side issue and a deviation from the topic in hand.
The electric gear is so arranged that the motor is started and stopped each time the rudder is started and stopped, and the current is entirely cut off when the rudder is at rest. Although a small amount of heat is generated in the rheostat controlling the motor, it is quite insignificant as compared with the heat from the steam engine, and is not sufficient to cause the least annoyance in these compartments. The wardroom of the Des Moines is located not more than twenty feet from the steering engine room, yet no inconvenience from the heat therein has ever been experienced, even in the tropics.
Taking a few figures to prove this, we find that, with the temperature at 82° F. in the shade on the bridge, that of the steering engine room was 98° F. Again, with 78° F. on the bridge, the steering engine room showed 92° F. Considering that these figures represent a contrast between the bridge and the steering engine room, and that the temperatures inside the ship must of necessity be considerably higher than those on the bridge, it is evident that the temperatures in the steering engine room are not excessive, to say the least. By far the most convincing argument, however, is the statement of a quartermaster that "in the old days when we had steam steering on here, we could dry clothes in the steering engine room in twenty minutes, but now that place is no good for drying clothes."
Again, the electric motor having a perfectly balanced armature, the vibration in this part of the ship is naturally much less than with the steam engine with reciprocating parts.
The electric installation on the Chester (and with a few minor differences, that of the Des Moines is exactly the same) includes the electric motor with disc brake, installed in what was formerly the steering engine room compartment, the main automatic controller and resistances just forward of the motor, and in the compartment where the hand gear is located, a limit switch installed in the screw gear room, and three master controllers or steering stands, one on the bridge, one in the chart house and one in the "motor room." On the Des Moines this third stand is located on the quarterdeck. Within the steering stand is a reversing switch for governing the main automatic controller in the "motor room." This reversing switch is operated by the lever shown in the cut, and closes the circuit through several contact fingers. A latching device retains the lever in the center or off position, and pressure of the hand on top of the lever releases the latch, while a centering spring acts to return the lever to the off position. Also, should the hand be removed from the lever in any running position, it will immediately restore itself to the off position, when the motor will be instantly stopped. The stand is so arranged that a small movement of the lever causes the motor to start and run at a slow speed. A further and relatively large angular movement causes the motor to accelerate at once to full speed. Throwing the lever in the reverse direction reverses the rudder motor, so that it is simply necessary to throw the lever to starboard or to port according to the direction in which it is desired to move the ship. About 6o degrees' movement of the operating lever in either direction gives full control, including starting, stopping, slow and fast speeds and reversing. This feature commends itself, especially where quick work at the helm is necessary.
All of the metal parts of the steering stand are of brass, and no magnetic interferences from changing loads were occasioned by installing the stands near the compass. It seems hardly probable that the small currents adjacent to the compass could have any effect thereupon, specially protected, as they are, in brass coverings, with- no exposed or bare parts. As no follow-up control is here involved, the rudder will keep on moving as long as the operating lever is held in a running position, and is stopped at any angle by returning the operating lever to the off position. In case of a casualty to the helmsman in time of action, this fact would undoubtedly prove to be an advantageous one. Should the rudder for any reason keep on moving, the limit switch, which is provided to prevent the jamming of the gear at the hard-over position, will function. With this type of control the position of the rudder is at any instant determined by reference to the helm angle indicator, located adjacent to the steering stands.
The general arrangement of the main control panel is shown in the cut on page 83, the front cover, with which the enclosing cases are provided, having been removed, for purpose of illustration, when the photograph was taken. This cut shows the controllers to consist of a switchboard upon which are mounted a number of electrically operated switches, which commute the connections to the main motor and govern each of its operations, which includes starting, stopping, accelerating and slowing down. In addition an overload device is provided which, in the case of extreme overloads, automatically limits the current on the motor to a safe value, and by its use the necessity for circuit breakers and fuses is obviated. The electrically operated switches not only provide a very effective means of commuting the main motor circuits, but they obviously do away with the necessity of running heavy control circuits throughout the ship to the steering stations. The current required to operate the electrical switches is but a fraction of an ampere, and for this reason can be carried on a wire of very small cross-section. Therefore, the contacts for the limit switch and the master controllers need only be rugged enough to handle these small currents.
All of the contactors are provided with heavy laminated contacts, and also with arc-rupturing, easily renewable auxiliary contacts; the switches are also provided with powerful magnetic blowouts. These switches are of very rugged construction and seem to be easily capable of standing the repeated operations required of the steering gear. The resistances used in connection with the controller, which are installed against the side of the vessel at the rear of the panel, are of the Cast Iron Grid type and are especially designed for heavy duty. As mentioned above, the heat generated is indeed slight as compared with that from the steam engine.
In the upper left-hand corner of the photograph of the main contactor panel is seen a selective switch, by means of which the control can be delegated to any one of the three steering stands, and which also makes it impossible to steer from more than one station at a time.
The limit switch installed in the screw gear room is shown in the cut below, and contains, within an iron frame with removable sheet metal cover, a drum cylinder equipped with contact segments, and is provided with a centering spring device for bringing the cylinder to the central position. The lever fastened to the drum shaft is arranged to be operated by dogs connected to the traveling nuts of the screw gear. The secondary circuits from the control station to the main contactor controller are connected in series with this switch, so that when the rudder reaches either of the hard-over positions one of the circuits is opened and the motor stopped. The connections are then such that the rudder can be brought back in the reverse direction by movement of the steering stand lever in that direction. When the rudder moves away from the extreme limit position, the switch is restored to its normal position automatically by the centering spring.
The combined motor and disc brake is shown in the cut on page 85, and is of the make of the Diehl Mfg. Co. It is 75 H. P., 250 R. P. M., at 120 volts. The motor was especially designed, with sufficient capacity to operate the rudder under severe conditions, and is also provided with a heavy overload capacity, to take care of the extreme conditions when the rudder is put hard over with the vessel going at full speed ahead. The windings of the motor, 50% series and 50% shunt, giving variable speed and torque characteristics, take advantage of the variation in load from the center to the hard-over positions, giving a quick response to the rudder, especially in the central angles, and also permitting the installation of an equipment of smaller rated horse-power than would otherwise be required.
It is quite evident that no attempt has been made to enter into the minute details of this gear. Instead, a general description has been given, or an introduction, so to speak, for the benefit of those younger officers of the service who are not familiar with such methods of steering. From the intimate relations which I have had with this method of steering, from the most excellent results which I have seen produced, and from the numerous advantages which it seems to possess over any other method in use to-day, I cannot help but feel that the electric steering gear is up-to-date, and furthermore that it has come to stay.
In summation of the above remarks, I would say that at the time of the present writing, Nov. 15, 1912, the Des Moines has covered 3600 miles in continuous service, most of which was done in the tropics, during which time the electric steering gear was used constantly without a single breakdown of any kind.