The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

312 , THe MarRINE REVIEW ~ _ September, 1909 ft. draught. The pontoon frames are | spaced 3. ft..4 in, apart The trusses | are built of diagonals and vertical : struts with natural knees at bulkhead corners. Each truss is further stiffened by two long 10 x 10 in. struts leading from each side of the central bulkhead to the wash bulkheads under the inner wing walls. Over 1,000,000 ft. of lum. ber and 150 tons of metal fastenings were used in the construction of the dock. Wherever possible, both in the pontoons and in the wings, bolts were | used and provision was made for the removal and renewal of the construc- tion members. Strain sheets were calculated for the varying conditions and compression strains were limited to 1,000 Ibs. per sq. in. with, and 200 Ibs. across, the grain of the wood. All water tight work was made double thickness, with heavy felt between the courses. The center line bulkhead was laid up with double diagonal 3 in, _tongued and grooved plank, and _stiff- ened by 8 x 8 in. uprights and knees with heavy stringers at top and _ bot- tom. There are four transverse bulk- heads extending up fo the top of the wing walls, giving ten water tight com- partments in the pontoon and five in each wing wall. The wash bulkheads under the inner wing walls are not water tight. The wings are fitted with overflow boxes, preventing more than oe «th - 686 OF =, @ 5 ft. of water being left in the wing walls when pumping from the inain pontoon begins. The pumping machin- ery consists of two 20-in. centrifugal a 4 pumps, driven by double engines located ES + on top of the wing walls. The pumps are on the pontoon deck and are con- nected to a stiction box, as shown, with a foot valve between. Suction pipes 12 in. diameter lead from the suction box into each of the five com- partments of the pontoon, with a gate valve in each, contro'led from engine room on top of the wall. Pumping from all the compartments on one side of the dock can be conveniently con- trolled from the centrally located en- gine house. The suction boxes on each side of the dock are cross-connected by a 16-in. pipe with gate-valve cutout, so that the entire dock may be pumped with either pump. <A priming box is built over the discharge of the pumps outside of the dock. Steam for each engine is furnished by a separate ver- tical boiler. Ceo oc I ri Im ooo I I '0D M90G AUG NoosuQ wos MOOG ONILVOTY AO NVIg 'Iva4aNay The wing compartments have com- municating valves and each compart- ment is provided with flooding gates operated by rack and pinion from the top of the wing walls. A float in each compartment is connected to a_ dial Z a rs indicator located in the engine room, z ié. _ << -8-82