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October, 1924 MARINE REVIEW 405 NEW MOTOR VESSEL BUILT FOR FORD MOTOR CO. Oil engine driven freighter Henry Forp II loading her first cargo of Iron ore. iron ore south to the Ford blast furnaces at River With her sister ship Brnson Forp, she carries coal northbound and Rouge, Mich. LS tanks and has a capacity of 3500 gal- lons per minute when operating at 720 revolutions per minute against a static head of 20 feet. The pumps are set in the bottom of the dock and are raised about 2 feet off the floor. Dis- charge is under water for all the tanks, a flap type of check valve being sup- plied so that the water can not back up into the pump. The two motors are direct-connected by a 20-foot shaft and are equipped with hand starters. Suction and discharge openings on these two pumps are 10 inches in diameter. The maximum deadweight lift of this floating dock is estimated at 500 tons. The total amount of water to be pumped out of the dock within the time specified, is equal to the dead- weight of the ship being lifted plus sufficient water which was used to overcome the buoyancy of the dock in order to sink it. Estimating that the buoyancy will require 14% times the actual weight of the ship being lifted, 500 tons, this means a total of 1250 tons of water to be handled in 60 or 70 minutes. The static head in a floating dock is changing constantly during the pump- ing operation. It is generally esti- mated by the mean or average head at which the average capacity must be pumped. The static head in a prob- lem of this kind will be represented by the difference in the water level in the pontoon and the water level outside the dock. It is found that in all cases, the mean _ static. head will be approximately two-thirds of the maximum. static head, which in this particular case, after adding 4 feet for pipe friction, is 20 feet. Particular attention must be given in the average floating dock to having the pump primed at all times, and under all conditions. This is done by having a foot valve on the suction pipe of the center compartment. Comparison of the floating dock of today with those of but a decade ago, however, reveals the tremendous strides made in the direction of larger, more dependable and generally more efficient units. Frisco Harbor Board Has Oil Storage Tank The state harbor board operates a fleet of tugs, pile drivers, and dredgers in repairing and maintaining the harbor at San Francisco. All of these are oil burners. In order to provide a large storage capacity for the oil used by this equipment, a subterranean oil storage tank has been built just back of the Embar- cadero about 200 feet from the bay. A large pipe extends from the oil tank to the bulkhead. Oil for the storage tank is delivered to this point in barges by the oil company and pumped through the pipe to the concrete storage tank. Over the subterranean oil tank is an electrically operated oil pump which draws oil from the tanks of the barge into the concrete storage tank or de- livers oil from the storage tank to the bulkhead. Here the oil supplies the barge maintained by the harbor board to deliver fuel oil to its dredgers, pile drivers and tugs. This oil barge is brought up to the bulkhead and connection made with the valve by means of flexible hose. The oil pump is then started, which quickly delivers the oil into the tanks on the barge. This barge then is towed to the pile driver or dredger and by means of a flexible hose, connection is made with the tank aboard the vessel to be fueled. A duplex pump is on the oil barge, and this is connected to the steam boiler of the dredger or pile driver, by means of a hose, the steam from the boiler serving to operate the duplex pump. ? tilts grated pe eererve rs OIL PUMP AND DELIVERY VALVE FOR SUPPLYING OIL TO VESSELS ON SAN FRANCISCO BAY