SIDE LAUNCHING OF SHIPS ON THE GREAT LAKES. 

 By Frank E. Kirby, Esq., Honorary Vice-President, and Edward Hopkins, Esq., Member. 



[Read at the twenty-sixth general meeting of the Society of Naval Architects and Marine Engineers, held in 



Philadelphia, November 14 and 15, 1918.] 



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With the advent of iron and steel shipbuilding on the Great Lakes, together with 

 the fact that the location of most of the yards was not advantageous for end launch- 

 ing, though occasionally small vessels are launched endwise, side launching was 

 adopted and has continued to the present day. It is receiving consideration and has 

 been adopted in some new yards that have been established outside of the lake 

 district. 



The preparation of the ground for building ships that are to be side launched is 

 much the same as for ships built for end launching, with the exception that the ship 

 is on a level keel when building. This is considered by lake shipbuilders as a great 

 advantage, not only for general accessibility, the saving of scaffolding, and block- 

 ing, but everything is plumb from the keel, which being level, no rake has to be con- 

 sidered. 



As most of the ships are built on permanent berths, and as these berths run 

 from 8o to lOO feet in width, this, with the inclination of the ways, usually from 

 1% inches to Ij4 inches to the foot, assures a height of keel blocking from 4 to 5 

 feet, which gives good working room under the ship's bottom. 



There are no extensive launching calculations required for side launching. The 

 accompanying plates illustrate how uniformly the ship is borne at all periods, and the 

 time from the releasing of the vessel until afloat is so short that no undue stress is 

 placed upon the structure. Of course the necessary calculations for stability after 

 launching are determined, no matter what method is adopted. 



Side launching is especially adapted for repair yards where the graving dry 

 docks are used for launching slips, as illustrated in the plan of the Toledo yards. 

 (Plate 69.) 



The methods used and arrangement of the building berths for side launching 

 are, for all practical purposes, the same in all lake shipyards. The methods and 

 arrangements used by the Toledo Shipbuilding Company are taken for illustrating 

 this description, excepting that the cross-section of the building berth is of one that 

 has reinforced concrete groundways and shoring stringers, this being the only one 

 of the type in use by this company. The other berths used are of the usual type, with 

 piling and timber shoring stringers and supports for the groundways, which are 

 usually of oak or fir. They are placed between the keel blocks about 10 foot centers, 

 extending from the inside bilge to the water's edge. 



On the concrete groundways illustrated, the lower half is covered with oak 



