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Diesel Direct Drive Selected in Rebuilding Ferry senger ferry PrRALTA formerly owned by the Key System Transit Co., Oakland, Calif., have been pre- pared by the Puget Sound Naviga- tion Co., Seattle. The PERALTA was built for the Key System Transit Co. in 1927 as a pas- senger ferry for use between Oak- land and San Francisco. In the fire which destroyed the Key Systems’ Oakland mole, this ferry was in one of the slips, but on account of the boilers being cold, could not be moved and she burned to the main deck. Built as a double ended ferry, the PERALTA was driven by independent direct current electric motors. The turbo-electric generator unit was of a capacity to supply the necessary power for the 2600 shaft horsepow- er on the propelling shaft for the two hours on the duty cycle and for 2250 shaft horsepower on the pro- pelling shaft for continuous duty. In regular service the boat was op- erated at about 1500 shaft horse- power on the propelling shaft. During the speed trials a maxi- mum speed of 15.15 knots was ob- tained. The hull of this ferry and most of the machinery did not suffer any damage at all and was purchased by the Puget Sound Navigation Co. to be rebuilt into a single ended ve- hicle and passenger ferry. Pierce for rebuilding of the pas- The management of the Puget Sound Navigation Co., recognizing the demand in modern transporta- tion for faster and more frequent service, decided that the _ rebuilt ferry should have a working speed of 17% knots. To obtain this it was necessary not only to increase the This article is an abstract of an an- nouncement issued May 1, 1934, by the Busch-Sulzer Bros. Diesel Engine Co., St. Louis shaft horsepower, but also to de- crease the displacement tonnage. Based on the company’s experi- ence with the 2200 shaft horsepow- er motor ferry CHIPPEWA, in service for 23 months without missing a day and with a record of more than 10,- 000 hours of operation in which she has traveled over 160,000 miles and during which time the engine re- sponded over 90,000 times without fail, a 3000 brake horsepower. Busch-Sulzer 10-cylinder, single-act- ing, trunk piston, diesel engine of the same type was selected. Plans call for an entirely new su- perstructure arrangement with an automobile capacity of 110 cars on the main deck and a passenger seat- ing capacity of 1500 on the upper deck. The beam over all will be reduced from 70 feet to 56 feet 6 inches which will still allow for three lanes of cars on either side of engine room casing. A careful study was made with regard to power plant equipment and arrangements, and _ considera- tion was given to the original turbo- electric double ended drive, turbo- electric single ended drive, diesel electric single and double ended drive, and diesel direct single end- ed drive. Diesel direct drive was chosen because it was found to make the desired speed increase pos- sible and to give the highest pos- sible operating economies. It also resulted in the simplest possible ma- chinery installation. Comparison of Machinery Weights AS can be seen from the tabula- tion of machinery weights, given be- low, the 3000 shaft horsepower Busch-Sulzer trunk piston engine re- duces the weights 36 per cent and at the same time a 33 per cent pow- er increase is effected. (a) Steam electric double ended drive 2250 shaft horsepower continuous with 2°0 kilowatts auxiliary turbo generator unit. Weights are given in pounds. 4— Boilers (Ary) ccciscccccsscossceseseeoes 394,000 1—Main turbo generator unit COM plete cis Geli cw iin 112,150 1—Auxiliary turbo’ generator WHIb= Completed sia cancnk 16,800 1=—Condenser: Cdry) iiss 38,750 Control and switchboard ...... 18,100 Cables, conduit and wiring.. 30,000 Piping, valves, pumps, air ejectors, fuel oil heaters, feed water heaters, ete..... 45,000 2—Double armature propelling INOCONS ) cc isscesscessnels succes ceca eeanebones 181,600 2—Propellers, Dearing iAticcaiventtinnenc 45,000 Normal fuel (1% bunker ca- PACILY) oairiaie a 255,000 Normal fresh water (% bunker: caps): osc5. sais 172,000 Total weight in pounds includ- ing normal fuel and water ready for service ...... @isswe 1,308,400 Machinery weight excluding fuel: water ase 881,400 Total weight per propeller shaft horsepower ready for SeRVICE Ue are A ees 581.5 Weight per propeller shaft horsepower excluding fuel ONG WACCY: bets tiie ce 391.7 In addition to above, two trim tanks of 60 tons capacity are pro- vided at each end of boat. (b) Diesel direct drive, single ended 3000 shaft horsepower continuous with 400- kilowatts auxiliary generator unit (all fresh water cooling). Weights are given in pounds: 1—Propelling unit with standard equipment, blower with motor ........ 253,000 1—Propeller, shafting and Dearing sc hck ities 40,000 2—Starting air tanks .......... 48,000 Oil and water cooler...... 24,000 Pumps and motors, ete... 63,500 Piping, filters, strainers.. 20,000 1—Combination exhaust & oil: fired: boiler’ .sc:achc: 16,000 1—Auxiliary diesel generator unit, 400 k.w. with sub- Base ee ea ee 116,500 Platforms and _stairs...... 3,000 Switchboard, wiring, transformers: “skincan. 7,500 Fuel oil (one week’s sup- DIV eee ere 150,000 resh® water iiei nce 110,000 Total weight ready for serv- 4OE Scnecdtnscetee eee 851,500 Machinery weight excluding Piel Se Water Gens kiessssi cess 591,500 Weight per propeller shaft horsepower for service...... 283.8 Weight per propeller shaft horsepower excluding fuel ONG: Water 3..ccce ce 197.1 Saving in weight, diesel di- rect drive over turbo-elec- tric double ended drive, ready for service, pounds.. 456,900 Saving in weight, diesel di- rect drive over turbo-elec- tric single ended drive, ready for service, pounds 334,000 (Continued on Page 40) oO Proposed outboard profile of diesel drive ferry as reconstructed from the ferry steamer Peralta MARINE REVIEw—June, 1934 21