TO SHIP CONSTRUCTION. 237 



As the result of experience with work such as I have descriljed, the AdmiraUy has con- 

 chided that, ahhough it is perfectly easy for a skilled welder to make, for test, welded joints 

 that will give the satisfactory results that have been referred to in this paper and discus- 

 sion, yet in building- a ship there arc difificulties on account of the complicated nature of 

 the structure and its rigidity, that result in very dififerent conditions to those attending the 

 welding of two simple plates. The system of assembly for welding so far adopted in Great 

 Britain is that referred to in this paper as the rigid system. Under that system lapped joints 

 have been successfully made and have been satisfactory on service. Particular care must be 

 paid to arranging the joints so that the main part of the welding is downwards, not upwards. 

 Difificulty has, however, been experienced under that system with butt welds, particularly 

 with butt welds of thick plates. Such difificulty had previously been experienced with heavy 

 test pieces ; accordingly it was originally decided to limit butt welding to plates of 25 pounds 

 and under. Now, in the light of experience on service, the Admiralty has decided to limit 

 butt welding to 15 pounds and under, where strength is important, until further experience 

 has been obtained, when it is expected that it will be possible to go to thicker plates. 



Mr. Joseph W. Isherwood, Member: — Was that a horizontal weld or a perpendicular 

 weld ? 



Commander Goodall: — That was a vertical weld. Reviewing the situiation, the ex- 

 perience obtained with the work I have described has led the Admiralty to lay down, in 

 regard to warships, the principle that electric welding for structural work, subjected to high 

 stresses, may only be adopted where it is possible to test the work in a manner representing 

 the tests to which the joints will be subjected on service. 



Mr. Charles P. M. Jack, Member (Communicated) : — The application of welding to 

 shipbuilding is of the utmost interest and importance, and the able paper under discussion 

 should do much to show the possibilities and clarify some of the mysteries connected with 

 the art. 



The special reference to a design prepared by me under directions of the Design Com- 

 mittee of the Emergency Fleet Corporation, Welding Committee, seems to call for some 

 explanatory remarks. 



The design was prepared primarily to show advantages which might be looked for in 

 ship construction, due to the introduction of a radical departure from existing methods of 

 construction by the introduction of joints of high efificiency, being assured by the Electric 

 Welding Committee that the following joint efficiencies could safely be taken: — 



Efficiency' in tension. 



( 1 ) Joints of fore and aft plating 100% 



(2) Joints of transverse plating overhead welding, 80% 



( 3 ) Joints of transverse plating vertical welding 85 % 



(4) Joints' of transverse plating flat welding 90% 



(5) All joints in compression 100% efficiency. 



It was decided to abandon the customary shift of butts in shell plating and to run all 

 the plating transversely, except the major longitudinal strength members; namely, the shear 

 strake, deck stringer plates, bilge strake and keel. Scantlings of these longitudinal strength 



