198 ELECTRIC PUMPING EQUIPMENT AND NOTES OF INTEREST ON 
ation at one time, depending entirely on the capacity of discharge pipes to the shore 
tanks. Any number of commodities can be discharged at the same time without 
mixing, depending, of course, on the number of discharge lines that are available to 
the shore tanks. The discharge lines from the pumps are so arranged that they can 
be also used as filling lines to each individual tank, by means of a bypass around the 
pump. 
Both Mr. Kibele and the writer, from the start, believed that half the number of 
pumps would meet all requirements, but finally decided to take no chances on the 
first installation. The better and more economical plan would be to connect the 
smaller number of pumps to a common 6-inch suction line, fitted with gate valves at 
each bulkhead and independent suction to each tank. This would enable each pump 
to draw from all or any of the tanks and insure maximum flexibility in the event of 
one or more pumps going out of commission. 
All operating valves are located on the upper deck. The motor control for 
starting the pumps is located in the main engine-room and will be described in 
more detail hereafter. When it is desired to start any particular pump, the deck 
officer gives the signal to the operator in the engine-room. Pumps are thus under 
direct control at all times by the engineer on watch. 
Since the La Brea went into commission she has handled over 500,000 barrels 
of oil, and in each case the discharge was completed with a material saving in time 
as compared with vessels with ordinary pumping system. 
The capacity of the pumping system is, of course, regulated by the capacity of 
the discharge lines and the pressure that the pumps are subject to. On a low-dis- 
charge head, and with ample shore connections, the entire cargo could be discharged 
in approximately 10 hours time. The maximum quantity of oil handled per hour 
against a pressure of 110 pounds per square inch is reported to be 4,200 barrels. 
The economy in fuel saved with this pumping installation appears to be approxi- 
mately 45 per cent over the ordinary manner of discharging a liquid cargo. 
After it was determined to use this system of pumping, with a pump in each in- 
dividual tank, the most logical way of driving the pumps was by independent elec- 
tric motors. In determining the proper type of motor, several propositions were con- 
sidered. Inasmuch as the drive of the pump was vertical, both vertical and horizon- 
tal motors were considered. Twenty-five cycle would have permitted using a slow- 
speed vertical motor suitable for direct connection to pump without any gearing, 
but this necessitated the installation of special 25-cycle turbine generating sets. The 
higher speed of 60-cycle motors required connection to pump through vertical gears 
if vertical motors were used, and this was not considered practical. The horizon- 
tal motors, whether 60 or 25 cycle, required the use of bevel gears. All the power 
companies operating on the Pacific coast and the various refining and loading sta- 
tions of the Union Oil Company use 60 cycle, and the installation of 60-cycle mo- 
tors had the advantage of being able to use shore power to drive the cargo pumps 
if required. For this reason, and also on account of long shipments required for 
the vertical 25 or 60-cycle motors, it was decided to use the horizontal 60-cycle type. 
