84 NOTES ON RIVETS AND SPACING OF RIVETS FOR OIL-TIGHT WORK. 
Commander Van Keuren has greatly enhanced the value of the paper by further 
description and analysis of the tests conducted at the New York Navy Yard, together 
with a statement in great detail regarding present practice for oil-tight riveting for 
United States naval vessels at that yard. 
Mr. J. W. Stewart gives many valuable suggestions and speaks with authority re- 
garding the reasons for much of the present-day practice. J am sure his remarks will be 
carefully studied and found most instructive by all interested in oil-tight riveting. It is 
gratifying to note that Mr. Stewart agrees with so many of the views expressed in the 
paper. 
Messrs. Rigg, Norton, and Morrell have thrown interesting side lights on practi- 
cally all of the points presented. Mr. Rigg brought out a point that was in my mind in 
connection with double bounding bars. Double bars were introduced to back up the 
caulking before the advent of longitudinally framed tankers and when the bulkhead plat- 
ing was not so well supported in this vicinity to resist deflection. It might be said now 
that practically all new tankers are longitudinally framed and that the panel of the bulk- 
head plating is so reduced by the bracket connections that deflection is reduced to a 
minimum, and on that account it is not considered that the caulking on a single bounding 
bar requires additional support. Mr. Morrell points out that one objection to double 
bounding bars is the void space between the heels of the two bars where oil, water or rust 
may collect and prove a source of contamination when carrying lighter cargoes. During 
the war the S. S. Richmond was chartered to carry four cargoes of gasoline to London. 
In order to clean out the tanks they were filled with distillate and pumped out several 
times, but as soon as the gasoline was loaded it became discolored and had to be pumped 
out and passed through the still for re-conditioning. The gasoline was again loaded into 
the tanks and became discolored a second time before it was discovered that the contami- 
nation was due to the residue lodged between the heels of the double bounding bars. In 
order to eliminate the source of contamination, this residue was expelled by drilling and 
tapping into the objectional space and forcing in polymeric with a putty pump. This 
was a very expensive procedure, and the necessity for it would not have arisen had a 
single angle or T bounding bar been fitted. 
Oil-tight riveting is such an illusive subject that apparently conclusive arguments 
can be advanced on both sides of many of the questions that vex the shipbuilder. One 
operator, in explaining why he favored double bars and countersunk heads and points, 
stated to the writer that when they carried gasoline it was their custom to first fill alter- 
nate tanks and follow up on the dry side in each case with a gang of caulkers. This 
could be accomplished with equal facility in the case of single bounding bars by having 
the bars face each other in alternate tanks and filling the rough side tanks first. While 
Mr. Norton is inclined to favor double bounding bars he would use panhead rivets for the 
reasons stated, and caulk on one side only. This was the usual practice when double 
bars were first introduced and is in line with the arguments advanced in the paper regard- 
ing panhead rivets. 
In regard to single riveting, we are forced to admit that this must be accepted in the 
case of many vessels converted and to be converted to burn oil, when carried in the 
double bottom, even in some instances where the test heads are as great as referred to by 
Mr. Rigg. It is difficult to reconcile Mr. Morrell’s arguments in regard to carrying 
mixed cargoes in view of the fact that he is building a 20,000-ton deadweight tanker to 
carry one kind of oil only. Mr. Norton, in his interesting description of this 20,o00-ton 
