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i66 a EL struction. The maximum radius is 86 feet and the minimum is 22 feet. The boom is 85 feet long from center to center of pins. At full radius 7000 pounds can be lifted. The hoisting speed, with full load, is 250 feet per NE problem in securing mate- YO rials to which the war loaned emphasis was that of obtain- ing satisfactory material for ship knees. With the development of the shipbuilding industry in America dur- ing the nineteenth century, the Amer- ican larch or tamarack, or hackmat- ack as it is more generally called, became recognized as the most val- uable wood for ship knees as it is hard and durable with a light spe- cific gravity. Hackmatack is not plen- tiful, however, its growth being con- fined to local sections in the northern part of North America. Again, but comparatively few knees can be ob- tained from one tree as they are Cat trom tiie point where the roots branch out from the trunk. In addition, it is difficult to obtain quantities of hack- matack knees in sizes over 6 inch- es. As the speci- fications for the 3500-ton Ferris- type ship, for ex- ample, call for 3, 6, 9. 10 and 16- inch knees, it is readily seen that a suitable substi- tute was urgently needed: Other woods have been tried but many of these did not give satisfactory re- sults. To meet the urgent de- mand for a sub- stitute for hack- matack knees, the Duplex Hanger Co., Cleveland, which _ specializes in wall plates, post caps, post Diarsie's; ° etc. as used in wooden building construc- developed fastenings for ship tion, use which are BASE FOR A WING STANCHION—FIG. minute. The traveling speed is 125 feet per minute’ and five revolutions can be made per minute. The cranes are steam driven, oil being used for fuel. The motions of travel, hoisting, swinging and raising or lower- slight modifications of the units used in buildings. The columns of a building and. the stanchions of a ship’s hold are de- signed to serve the same _ purpose in a broad sense, because building columns support floor and roof raft- ers, while stanchions support the vessel’s deck and hold beams. In comparing the two cases, however, a factor is present in ship construction that is absent in buildings. That is, building columns are invariably under compression only while a _ ship’s stanchions are often under a slight ten- sion when the vessel labors in a seaway. FIG. 1—-CAP AND BASE USED T0 FASTEN STANCHIONS TO HOLD BEAMS—FIG. 2—STANCHION FIG. 4—CENTER STANCHION BASE MARINE REVIEW 3—WING STANCHION CAP NEAR A HATCHWAY— March, 1919 ing of booms are controlled from the operator’s cab. It is said that in actual use with coal for fuel the 10-hour consumption is 1200 pounds, 1000 gallons of water being used in the same time. Knees for Wooden Vessels Fig. 5 shows how the Duplex com- pany’s products have been adapted for use in wooden ship construction. Each fastening consists of two side plates, A, and a distributing plate, B,. The distributing plate prevents the stanchion from gradually forcing itself into the hold and deck beams for al- though the end wood of pine will easily stand a pressure of 900 pounds per square inch, the grain of the wood as it runs lengthwise begins to crush at a pressure of 250 pounds to the square inch. As the distributing plates are comparatively long, they distribute the strain of compression over a greater area, thus pro- tecting the hold and deck beams from _ becoming gradually crushed. These plates take the place of the hardwood distrib- uting blocks com- monly used in places where end grain timbers sup- port a load from a horizontal tim- ber. The _ side plates directly over the keelson are bolted through the stanchions and fastened to the keelson by means of lag screws. The _ side _ plates over and under the hold beams are also. bolted through the stanchions. Both units are firmly fastened together with bolts that pass through the hold beam. The plates directly un- der the (deck beams are bolted through the stanchions and the deck beams. The plates at the side of the hold beams take the place of the straps usually placed at. this