NEW 20,000-TON TANKERS. 39 
It would be interesting if Mr. Norton would investigate to see if the brackets which 
are increased to reinforce the longitudinals could not be made all of one size for duplica- 
tion without sufficient increase in weight to outweigh the advantages. For instance, if 
the 15-inch longitudinals require a 15 rivet bracket, say for single riveting, or a 22 or 24 
rivet bracket for double riveting, could sufficient weight be saved on the smaller longi- 
tudinals with span reduced by fitting the same over size bracket. If double-riveted 
brackets are adopted, they could all be punched the same, but as the bracket became 
excessively large for the smaller longitudinals, one row of rivets, or part of a row, could 
be omitted so that there might not be any greater number of rivets throughout. On 
the other hand, it appears evident that the smaller longitudinals require relatively 
larger brackets in order to equalize the bending moments. 
What attracted my attention most in the design, however, was the longitudinal 
distribution of weight. The length taken up by the cargo, notwithstanding it is increased 
by the long pump room located amidships, seems relatively short, and the machinery 
space and void space forward correspondingly long. I would like to ask Mr. Norton if 
he found the great length of machinery space necessary for a suitable twin-screw in- 
stallation or if, after arranging the distribution of cargo in the manner described, he then 
took what was left for the propelling machinery. 
It is well understood that the greatest stresses-in a tanker with the machinery aft 
are in the deck and in the sagging condition on account of the void space at the ends 
which, on that account, should be reduced to a minimum. While there has not been 
much trouble with longitudinally framed decks, there have been several catastrophies in 
the case of tankers with transverse framed decks. One of these broke in two in ballast 
with the ballast concentrated in three or four midship tanks, and another carrying 
molasses broke because all the space could not be used and the cargo was concentrated 
amidships. From this it may be concluded that the position of the load in a tanker may 
in some cases be more important than if increased but with better distribution. 
It would seem that Mr. Norton might have claimed that the sagging moment was 
somewhat reduced on account of the large void space amidships due to the pump room, 
as this may be a redeeming feature. 
Mr. RoBert W. Morre ti, Member:—I have very little to add to the very valuable 
paper which Mr. Norton has presented, and, in fact, he was good enough to discuss it 
with me before it was presented, so there are practically no ideas which I can bring out 
which would throw any additional light on the subject. 
I might state, however, in connection with Mr. Frear’s remarks regarding the dis- 
tribution of the cargo space, that the cargo space was originally intended to provide 
cubic capacity for a quantity of heavy oil, and therefore made it necessary to distribute 
it over so great a length of the ship as would be necessary if the oil were of a greater 
volume. This naturally tends towards the shortening of the oil space and provides a 
greater space at the ends of the ship. 
So far as the distribution of the weight is concerned, with relation to the sagging 
and bending moment, I am assured by the builders that the bending moments work out 
much more satisfactorily with this vessel than they have on vessels of previous designs. - 
I think that is all I have to say on the subject. 
Mr. T. M. Cornsrooxs, Member (Communicated) :—I was very much interested 
