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driven auxiliary generator of 200 kil- owatt capacity is also provided for use either as a standby or for port conditions. Each of the turbine- driven sets is provided with its own condenser. The auxiliary electrification is one of the most complete ever attempted in marine service. The below-deck- auxiliary motors are practically all of the enclosed-ventilated type and pro- vided with automatic starters and a wide speed control by means of field regulation. The above deck auxili- aries consisting of the anchor wind- lass, capstan, boat hoists and cargo winches, are all electrically driven. The motors are of the totally enclosed type and furnished with automatic type of control. The winches, ten of which are of 3-ton capacity and four of 5-ton capacity are of the worm gear noiseless type with five speeds in both the hoisting and lowering direction. Other departments of the ship have made full use of electrical apparatus for promoting safety, comfort and economy. The thermo tank system of heating and ventilation is used for controlling the temperature of the air and 52 motor driven fans, having a total capacity of 170,000 cubic feet of air per minute, are used for the ventilation of the cargo holds, hull, and living quarters. In addition to the foregoing, there are also 200 bracket fans situated in the various staterooms and public spaces. The SANTA Rosa and its sister ships portray the great advancement made in marine engineering during the past ten years, and as far as one can fore- see, such ships are not to be outmoded ~ for many years to come. Diesel Electric Drive Diesel electric drive was adopted for the first time by the United States navy, when it launched the yard tug 119 from its Charlestown navy yard at Boston. The tugboat, which is 100 feet in length and built specially for harbor work on the Atlantic coast, is powered by means of two main diesel engine-driven generators of the sepa- rately excited type, each rated 260 kil- owatt, 300 revolutions per minute, 250 volts, and two direct connected, com- pound wound generators, each rated 35 kilowatt, 125 volts. The latter fur- nish power for both excitation and the ship’s auxiliaries. The propelling motor is of the double type, rated 640 shaft horsepower total, and drives a single propeller shaft at 125 revolu- tions per minute. The control is of the conventional variable voltage type with stations in both pilot house and engine room. The lighthouse tender WISTARIA, which is similar to the LINDEN and COLUMBINE previously commissioned, was completed during the year. The main jpower plant consists of two diesel engine driven generators, each rated 100 kilowatt, 400 revolutions per minute, 250-volt, compound wound, ane one propelling motor of the double type rated 240 shaft horsepower to- tal, 350 revolutions per minute, 500- volt. The main generators operate at constant potential and provision is made so that the auxiliary power can be taken from either generator. A mo- tor generator set is provided for the reduced voltage required by the lights while underway. For standby condi- tions at port, such power may be taken from batteries, from an installed sep- arately driven standby set, or, from short connections for which provision has been made. Reconditioned Cargo Ships The main propulsion units of eight cargo ships of the Hog Island type were rebuilt during the year to ac- commodate an increase in power of from 2500 to 3140, and an increase in propeller speed of from 90 to 100. Changes in the hull structure were made, which in conjunction with the increased power, give the ships a serv- ice speed of 13.5 knots. Other changes included the addition of limited pas- senger quarters and refrigerated cargo space. The eight ships upon which work was conducted during the year completes a program which involved a total of 22 ships. Six of the recently reconditioned ships are operated by the Black Dia- mond Steamship Corp., and have been renamed the BLAcK HERON, BLACK Eacir, Brack Gut, BLAack TERN, Buack Hawk, and BLAck FAtcon, and two ships, namely the DretMuNDo and DELVALLE, are operated by the Missis- sippi Shipping Co. In addition to the auxiliary installa- tions referred to in connection with the turbine electric and turbine gear drive ships previously described, a number of installations were made during the year which showed a de- cided progressive trend and advance- ment along new lines. Among these may be mentioned the complete aux- iliary installations on the SEATRAIN New YorK and SEATRAIN HAVANA, which are the first seagoing vessels to adopt alternating current motors exclusively for auxiliary purposes. In the past, such applications have either been confined to a relatively few Great Lakes vessels of special type, or to installations in which both direct cur- rent and alternating current motors have been used. Auxiliary Installations The speed characteristics of alter- nating current motors, which were considered insurmountable difficulties in the past, have been overcome to a great extent through the use of gear type motors (motors furnished with built in reduction gears), multispeed motors in which pole changing is used and motors of the wound rotor, slip ring type. In the installations on the SEATRAINS, all three types of motors were used. MaRINE REview—January, 1933 The design characteristics of alter- nating current motors make them very desirable for below deck service on ships. The elimination of commu- tators and brush rigging, the ease with which they maye be thrown across the line in starting without elaborate con- trol devices, the light weight, smaller dimensions, lower first cost, reduction in number of spare parts, and lower cost of upkeep are all in their fa- vor. Except for the application to deck auxiliary equipment in which graduated speed control is essential, the advantages may more than offset the disadvantages, and every ship in- stallation of the future, therefore, be- comes worthy of study. The mechan- ical features required to make _ the general service type of alternat ng current motor, such as is used in land service, applicable to marine service, have been developed. These features include such items as marine type in- sulation, design for satisfactory op- eration at a tilt, inclusion of water- tight connection boxes, and the proper shielding to prevent damage by fall- ing liquids or solids. The installations on the SEATRAINS consists of two turbine driven, alternat- ing current generators, each rated 250 kilivolt amperes, 1200 revolutions per minute, 8 p.f., 240-volt, 3-phase, 60- cycle. Direct current exciters are mounted on an extension of such gen- erator shaft. Constant Speed Motors The majority of the motors used are of the constant-speed squirrel-cage type, the exceptions being the motors furnished for driving the forced draft fans, fuel oil service pumps, and shaft turning gear. In the case of the forced draft fans and fuel oil service pumps, multi-speed motors with pole chang- ing features are used. The motors driving the forced draft fans have two speeds, 1200 and 900 revolutions per minute, and the motors driving the fuel oil pumps four speeds, 1200, 900, 660 and 450 revolutions per minute. The motors for driving the shaft turn- ing gear are of the slip ring, wound rotor type and c3n be graduated in speeds up to 1200 revolutions per minute, through the introduction of external resistance in the rotor circuit. The starting control equipments for all motors are of the magnetic across- the-line type. Remote control, start- stop push button stations are also pro- vided. A control, which consists of con- tactors switch and temperature over- load relay only, is contained in a drip- proof metal case with provision for operating the switch without opening the door to the case. A drum type pole changing switch is provided for the fuel oil service pump. The voltage is reduced from 240 to 120 for the light- ing circuits by means of transformers and additional transformers are also supplied for reducing the voltage to 30 for the searchlights. The search- lights are of the General Electric in-