98 SIDE LAUNCHING OF SHIPS ON THE GREAT LAKES. 



flitch 6 inches thick, forming the groundway. The upper half is of the usual size 

 timber launching way and is hinged about the center of the berth, so that it can be 

 dropped down until needed for launching, giving free access to the space below the 

 ship's bottom. 



The arrangement of the ways and launching tables illustrated are for a ship of 

 3,500 tons deadweight, of the type now building by this company for the Emer- 

 gency Fleet Corporation. The dimensions of the ship are as follows : — Length over- 

 all, 261 feet; beam, 43 feet 6 inches; depth, 21 feet. The length and beam are the 

 maximum that can go through the canals from the lakes to the sea. 



While the time required for side launching is very short, the launch is much 

 more spectacular than an end launch, there being usually a drop of from one to 

 three feet off the end of the ways. 



In a recent launching in one of the lake yards, the drop from the end of the 

 ways to the water was only one inch less than 14 feet. No damage resulted to the 

 hull structure. 



About three weeks before the date set for a launch, the groundways are placed, 

 and a week later the packing is placed under the ship. The triggers and daggers, 

 two sets at each end for a ship of this size, are put in position a week before the 

 launch, and three days before launching two patent key blocks are placed under the 

 keel at each end, these being the last keel blocks left under the vessel, and they assist 

 in relieving the stress on the triggers until the last moment. 



The triggers are levers, two at each end, pivoted against chocks secured to the 

 groundways. Daggers or shores extend from a point on the trigger just clear of the 

 chocks to the ship. At the other end of the triggers, bights of rope are turned, ex- 

 tending back and fastened to piles or other secure anchorage. These ropes are cut 

 with axes by men when signaled. The triggers and daggers drop away and the ship 

 is free to move. 



The signal device used consists of three vertical semaphores, shown on Plate 74, 

 pivoted to a platform located at each end of the ship, on the lower or water side of 

 the building berth and clear of the ship's way, in sight of each other and also in 

 sight of the men who are to cut the ropes, holding the triggers. 



About half an hour before launching, the wedging up or rallying is started; 

 first on the upper or land side until the shores drop out, then on the lower side until 

 the shores drop out ; then again on the lower side, rolling the ship so that the keel 

 blocks can be easily removed. The patent or key blocks, as before stated, are re- 

 moved last. 



The first of the semaphore signals is dropped when all the shore and keel blocks 

 are out, the second when the key blocks are out. Usually, at this period of the oper- 

 ations, the ship has moved a little, which is followed up by the jack shores fitted at 

 each end of the ship. If she has not moved, the jacks are worked until she moves. 

 The ship is now ready to let go, and the last signal is dropped to cut the ropes, which 

 is done simultaneously at both ends. 



The data from launch of the 3,500 dead- weight-ton ship are as follows: — De- 



