The following data are taken from the log of the S. S. West Conob, on voyage 1, San Francisco to Honolulu : Departure 9 :14 a. m., San Francisco Lightship, June 13, 1919.
Arrived 4:26 a. m. Honolulu, June 21, 1919.
Average knots per hour, 11.1.
Average fuel per day, 211.2 barrels.
Average fuel per knot, .8.
Revolutions per minute, 79.5.
The fuel oil capacity of the \Vest Conob is 6.359 barrels in double bottoms ; 1,100 barrels in after peak ; 2,141 barrels in each of two deep bottom tanks ; -and 320 barrels in the two settling tanks, making a total of 12,060 barrels. The oil storage tanks were filled to capacity when the vessel started on her first voyage to Hong Kong. Nineteen hundred and ninety-three barrels of oil were taken on at Honolulu ; 3,850 barrels were taken on at Hong Kong. On the return trip 2,100 barrels were taken on at Honolulu, the vessel having 1,047 barrels in the tanks when she arrived at San Francisco.
The West Conch is 423 ft. 9 inches in length over all, 29 ft. 9 in. depth and beam molded of 54 feet. Her displacement, light, is 3,751 tons ; loaded, 12,401 tons. She is equipped with a triple expansion reciprocating engine of the inverted type of 3,500 h. p. are 28% in. by 47 in. by 78 in. with 48-in. stroke. There are three Foster water tube boilers, each having a heating surface of 4,150 square feet, and 827 2-inch tubes and 52 4-inch tubes. The propeller is 17 ft. 1 in. diameter with a pitch of 15 ft. 3 in. and a developed area of 102 square feet. The designed speed is 11 knots an hour.
The- vessel is equipped with the Coen system of mechanical oil burning equipment. There are two duplex oil pumps 6 in. by 4 in. by 6 in. with a capacity of 30 gallons each per minute. These pumps are mounted one above the other, each being large enough to supply all the burners, thus one set is always held in reserve. They draw their supply from the settling tanks through a 4-inch pipe. The oil is pumped from one settling tank at a.time. The discharge pipes leading to the heaters are 3 inches in diameter reduced to 1 inch at the heater, of which there are three sets, with five heaters to a set. Two sets are operated at a time, the third being held in reserve.
The oil enters the heater unit between two shells and takes a spiral course upward to the space between the two shell heads from whence it flows down through the seamless steel coil and out to the discharge header. In the event of an operator's closing the inlet and outlet oil valves without cutting out the steam to the heater, thereby causing the dead oil in the unit to heat and expand to a pressure which might create a rupture, a safety valve is pro vided for each unit and set to operate before an excessive pressure can be attained.
Each individual coil is under control and can be cut in or out independent of the others. No cleaning is required except blowing out with steam. The inner shell being a floating mem ber eliminates expansion and contraction strains. The cold oil entering and circulating between the inner and outer shells acts , as an insulator, making covering of the units unnecessary.
A standard temperature for all fuel oils cannot be fixed for the "efficient temperature" will vary as the different oils vary in viscosity and gravity. However, a temperature ranging from '210 degrees F. to 230 degrees F. has been proven to be the most efficient stage for residuum fuel oil. Lighter oils require a much lower temperature. Heavy Mexican oils require a temperature ranging from 275 to 300 degrees F. The steam pressure to the heaters is reduced to 100 lbs. For stand-by the oil is maintained at a pressure of 30 to 35 lbs. and for full speed ahead 125 lbs. There are five burners to each boiler. The oil pipes leading from the heaters to the burners are 1/ inches in diameter and reduced to 3A-inch at the burner. The burner consists of a special angle valve, a short piece of tubing, a tip, a cap to hold the tip in place and a steel rod running through the burner to provide means for regulating the discharge from the tip. With this burner, the fire man has at his immediate command not only means for regulating the size of his operating fire, but means whereby he can instantly substitute a stand-by and vice versa, with one quick turn of the burner valve wheel. During the noon hour when tied up at dock, all burners are shut off except one.