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First Barge of This Type Takes te Water at Cleveland—Craft is Launched Endwise — Water Ballast Relieves Launching Strain EW methods of launching coa- N crete ships were tested success- fully at Cleveland — recently. The craft is the first large concrete vessel built on the Great Lakes, a car float of 1500 tons displacement which was launched by the Liberty Shipbuild- . ing & Transportation Co. Jan. 30. This vessel, which was described in Tur Marine Review, December, 1918, is 265 feet long, 37 feet 2 inches beam, 11 feet 3 inches deep, with a maximum draft of 9 feet 3 inches. She is’ the first to be launched of six which the Liberty company is building for the government. Equipped with tracks on their decks, these vessels will be used as car floats in east coast harbors. To launch a craft of this type end- wise is a distinct departure from the methods employed in Great Lakes prac- tice and the complete success of the undertaking is due to the careful plan- ning on the part of the Liberty com- pany’s engineering department. This vessel was poured in sectional forms which were so constructed that : they could be removed and used again. : The forms were supported by blocking. built on the standing ways. In making preparations for launching, the first step was to remove the two outer sections of the forms. This left the vessel sup- ported by the blocking under the center form on which the bottom of the vessel CD ENA ee YAP Se FIN eee NOE Ie Te eg ee Cormrec}“i19 SHE'S Z of Barge 2-22" Oar Z PBoO/t- Pate Ne pos eae LE SS Alrerriare /7erthod GY 4-4 412" Ooh Oultle NZ. TravasVverise Secr/os7 rested. The outside forms, however, ran to a point well inside the bilges. Next, cribbing was built up at a point just inside the bilges. This cribbing was supplied with wedges—not for the pur- pose of raising the vessel, however, but for just the opposite object, that is, to let her down after the middle forms were removed. After this cribbing was all in place, the center forms were re- moved and the running ways built in place on the standing ways. These were, of course, thoroughly greased and as the _vessel was still supported by the crib- bing, no. pressure was exerted on the ways to force out the lubricant. Thus the danger of the vessel not starting on her downward plunge as soon as she was released was practically eliminated. Letting the Vessel Down The next step was to knock out the wedges from the cribbing which let the vessel down on the running ways. At this time, all that held her were hemp cables secured to the running ways and a few emergency dogs to hold the run- . ning and standing ways together. Two of these dogs are shown in the accom- panying illustration. The standing ways were built with a pitch of 34 inches to the foot and ran to a point 80 feet from the water’s edge. When all was ready, the cables holding the running ways were cut and without P Ad 3 Oak Weages foSuir by OKO %E-0°Y P Wy YORCOPLIOCK'S pie Teasers WR SS 2-/0K10'% 20° VP (Toke Up Blocks 2-122 OAK SHACLS £-12'Kle" Ground Ways 2 sat Dak Lo/gitudina aL Sect! of? awake Spies By F. B. Jacobs a hitch the craft started. For an emergency, jacks had been provided. In figuring the launching calculations, provision was made to have the vessel lift due to the buoyancy of the water when the stern poppet was 2.5 feet back of the crest of the ways. This was accomplished by placing 100 tons of water in the forepeak. The calcula- tions were figured with such exactness that she actually lifted on her downward course within 1.2 feet of the point de- termined on. The addition of water in the forepeak reduced the breaking strain due to taking the water 100 per cent, the actual stress put on the vessel being a 4000-pound unit stress per square inch, The accompanying illustration shows how the fore poppet was swiveled to keep an even strain on the vessel’s bot- tom, the method used to tie sections of the running ways together and longi- tudinal and transverse detail sections. The object of the swiveled fore pop- pet was to insure an even bearing on the vessel’s bottom when she dipped while taking the water. The block and its seats are provided with a _ radius which was finished smoothly and_ thor- oughly greased to insure its working properly when under pressure. The sliders, or sections of the running ways, were tied together to prevent piling up under the vessel, if one left the ways. a S30 py 2 2G ':2 : bat Dog 3 : aa AN (ZB 2.°O1S B%o Fo 9 ead EE = 300 Wedges mom ol Be pot, 10X20". P &p Blocks I th Coblear CO, Popper igen oehede DETAILS OF METHOD USED IN LAUNCHING CONCRETE CAR FLOAT. THE FORE POPPET IS SWIVELED TO DISTRIBUTE THE STRAIN ON THE VESSEL AS SHE BECOMES WATERBORNE—THE SECTIONS OF THE RUNNING WAYS WERE TIED TOGETHER TO KEEP THEM IN PLACE Ve Soe ae PI Pare ee Cod ee i RS Tee eee