DESIGN AND CONSTRUCTION OF PASSENGER STEAMERS. 293 



to offer convincing proof of fuel savings possible for high-speed, moderate dimensioned ves- 

 sels. The 600-footer may be considered a moderate dimension vessel, but it is difficult to see 

 from what point of view tliere is an economic saving in fuel as compared with the 1,000-foot 

 vessel with a difference of only about 16 per cent in shaft horse-power and sometliing like a 

 difference of 200 per cent in displacement. 



Mr. David Arnott, Member: — I wish to congratulate Mr. Rigg on the very valuable 

 paper which he has contributed on the occasion of the annual meeting of this Society. A 

 paper having for its subject "The Design and Construction of Passenger Steamers" is oppor- 

 tune, if only in view of the probability that the shipyards of this and other countries will be 

 forced to eke out an existence for some time to come by the building of merchant vessels 

 of a type other tlian the ordinary freighter or tanker. 



Mr. Rigg has chosen to present a resume of the main considerations affecting the design 

 and economy of operation of passenger vessels rather than specialize on a particular branch 

 of his subject, but his paper is no less useful and is certainly much more readable on that 

 account. Plenty of opportunity is provided for discussion, as Mr. Rigg has the pronoimced 

 views which usually accompany long experience and does not hesitate to state his own ideas 

 even on such a delicate question as that of interior decoration. 



With regard to the interesting particulars given of the 1,000-foot liner, I would like to 

 ask Mr. Rigg if the design ever got beyond the very initial stages, as it seems to me that the 

 comparatively narrow beam of 105 feet, in association with a length of 1,000 feet and a 

 depth of 76 feet, is a return to the proportions of the Atlantic liners of a generation ago and 

 does not appear to accord with the trend of later practice toward increased breadth to which 

 Mr. Rigg draws attention. If 76 feet represents the depth of the uppermost complete deck, 

 it would be interesting to know how many tiers of deck houses were to be superimposed on 

 this deck. I wonder if this vessel, if and when built, would meet Mr. Rigg's idea as to the 

 proper metacentric heights for a modem oceangoing liner. 



While it is true, as Mr. Rigg states, that the structural design of a 1000-foot liner 

 would present no serious engineering difficulties, it is always a difficult problem to design 

 a satisfactory ship structure where economy in steel weights is so vitally important as to pre- 

 clude the piling on of material for the purpose of playing safe, a practice which, after all, is 

 mighty poor design. 



In a 1,000-foot ship designed for a speed of 30 knots, the panting arrangements at the 

 ends and the anchoring of the large deck houses would require very careful and special con- 

 sideration if trouble is to be avoided in these particular neighborhoods. I would like to take 

 issue with Mr. Rigg as to the effect on the weight of increasing the breadth and fineing 

 down the ends in a vessel of the same length and depth, and would suggest that the increase 

 in weight over the corresponding vessel of normal proportions and block coefficient would be 

 considerable in cases where the classification rule scantlings are required to be taken direct 

 from tables in association with any system of numerals. 



Mr. Rigg's reference to standardization is particularly appropriate at a time when econ- 

 omy in shipbuilding costs is of the utmost importance. The new British standard sections 

 provide British shipbuilders with a much more economical range of bulb angles and chan- 

 nels than we have available for shipbuilding in America. The new shapes are, weight for 

 weight, relatively much stronger than the old sections and are more easily rolled, while their 

 new standard channel is more suitable for machine riveting, the taper of the flange being about 



