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76 bound to claim much more considera- 'tion in the future than has been given 'to it in the past. The first cost is perhaps the most important 'one, but 'the economy of working and cost of 'upkeep would 'be considerably less than the present system of small en- gines. In. considering such a devia- tion from existing methods, it is al- ways difficult to prove the advantages until such a system has been tried; the strongest argument against the use of motors in the past years has been that they are not so reliable as the. steam engine, and the first cost is much greater. With regard to relia- bility, a motor constructed on modern designs and up-to-date practice is not more liable to derangement than other: machinery, and in fact with proper insulation and protection, there are fewer parts to wear and give trouble than in a steam engine, and given the same care and attention, breakdowns are a remote contingency. --In a report read by Mn. Longridge, of the British Boiler & Electrical In- 'surance Co., he states 'that the rate of Jbreakdowns among steam engines. for 12 months had been 1 in 10.5, gas and oil engines 1 in 10, electric motors 1 in 8. At the same time an armature or field could be replaced with spares in an exceedingly short time. The oil consumed is much less, there are no 'steam glands to leak and repack, and further, they are practically noiseless. One of the objections that the oil, steam and water in an engine room would have a detrimental effect on 'the insulation, would not hold good df actual. ptactice, as most of. these clbjectionable features arise from the auxiliary engines themselves in the shape of drains, leaky glands and joints, and also the splashing of oil from crankpins, swabbing of rods, etc., none of which apply to electric driv- ing. Auxiliary Pumps. - _ Dealing with auxiliary pumps, these are usually of the reciprocating type, with the exception of the main circu- lating pumps; but to the author's mind 'there is nothing in the duties of the whole pumping installation on 'board ship which could not 'be well and ef- fectively carried out 'by means of elec- trically driven centrifugal or turbine 'pumps, specially designed to meet the requirements. Turbine pumps 'have been made for boiler feed and have worked quite satisfactorily. The re- quired feed regulation can be effected by throttling the delivery of the pump at the check valves. Several well- 'known firms also make three-throw variable stroke pump for -boiler feed-- THe Marine REVIEW the feed regulation is effected by al- tering the stroke of the pump rams. The speed of the motor could also be varied within certain limits, by means of a float in the hotwell or feed tank actuating a shunt resistance. Where the amount of water exceeds say 3,000 to 4,000 gallons per 'hour, turbine pumps arranged to work in series, one coupled to each end of motor spindle, are at present made to deal with considerably higher pressures than are required for boiler feed; for less quantities than the above the three-throw type of Bump is recom- mended. ee 'If centrifugal pumps are adopted for bilge purposes, one of the difficulties that would 'be experienced is that when the pump has performed its duty of. discharging the water and air is drawn into the suction pipe, it will not start repumping without 'being re- charged. This can be simply done by means of a steam charging ejector connected to any convenient pipe. An- other point which would require con- sideration is that the passages by which the water travels to the suction rose would have to tbe free from ob- struction, otherwise water would not flow with sufficient speed to keep the pump supplied. In all other respects the centrifugal pump driven by a mo- tar would be superior to the steam pump, there being no valves to get out of order, no reciprocating move- ments, wear and tear is infinitesimal, the only parts which would be likely to require renewing are the carbon brushes on the motor. Main Pumps of Centrifugal Type. The main circulating pumps as now fitted are almost invariably of the centrifugal 'type, and it is surprising that motors have not been. adopted for this purpose, the conditions being in every way suitable, the load being practically constant, electric motors would ibe an ideal method of driving. The author believes that this system of driving ballast pumips, wash deck pumps and sanitary pumps thas been adopted by the admiralty, who are fully alive to the advantages. Motor drive for turning gear for the main engines 'has 'been adopted in the latest Cunard steamers. Electric ash hoists have been successfully installed for some years in cross channel steamers and naval ships, 'they have a very great advantage in being much more silent than steam engines! and quite as easily handled. A familiar type is arranged to work by means of friction discs fitted inside the drum, half the discs engage with feathers in the drum, and loose on the shaft, the oth- tion, "tion, . kept moving May, 1900. er half engage with feather keys on the shaft; the lowering is done by let- ting the barrel revolve free, the mo- tor runs constantly in the same direc. an automatic arrangement js fitted to prevent overwinding. ~The whole arrangement is very simple and not liable to get out of order. Electric Drive to Steering Gear, : The application of electric drive to the steering gear is perhaps not quite such an easy problem as the other cases mentioned, as the conditiony are much more any machine which can be driven by complicated, but surely means of a steam engine, can also be driven electrically. Remembering what has been 'done in textile mills, colliers, 'steel works, etc., the steering gear problem is not insurmountable if tackled without 'bias. The power re- quired is intermittent, it must be ap- plied instantly in exact proportion to the work required, and the starting and stopping must be automatic and correspond to 'the steering wheel. These conditions could be achieved by means of a shunt wound motor, coupled to the ordinary gear instead of the usual engines, the shunt being 'excited direct from the main genera- tor, the current for the armature being taken from the dynamo side of a mo-- tor generator, the motor taking current from the main generator. The shunt of this dynamo would also be separ- ately excited from the main dynamo, a regulating rheostat would be inserted in the field, and also a reversing ar- rangement fitted, both to be actuated by means of the existing steering wheel in the wheel house. When the steering wheel is in mid-position the dynamo field would be cut out and the whole resistance in the shunt; as soon as the wheel was moved in either direction, the field circuit would be made to operate in the same direc- and at the same time would commence to cut out the resistance, allowing the dynamo to generate suffi- ecient current to. operate ttle steering motor; as soon as the steering wheel came to rest, the motor would be stopped by means of the existing dif ferential gear, which would cut out the field and bring the lever back to its original position in exactly the same manner as it would close 4 steam valve, and in the same way if the steering wheel were moved rap- idly round to port or starboard, it would cut out the whole resistance, and the motor would run at full speed so long as the steering wheel was stops would be fitted as at present, so that the wheel could