70 NOTES ON RIVETS AND SPACING OF RIVETS FOR OIL-TIGHT WORK. 
DISCUSSION. 
THE CHAIRMAN:—Gentlemen, this paper, No. 5, entitled ‘‘Notes on Rivets and 
Spacing of Rivets for Oil-Tight Work,” is now open for discussion. 
Mr. E. H. Ricc, Member:—This subject is a live one at the present time. Oil 
tankers and oil-bunkered ships are in demand, and their economical construction is one 
of the problems exercising the staffs of all our large yards and of some yards not so large. 
The troubles in the coal mines all over the world, the ease of handling oil at the 
ports and in bunkering ships and the greater thermal value of oil all tend vigorously to 
increase its use—a point which was brought out more effectively by Mr. Ferguson this 
morning than I can hope to bring it out now. 
Our modern merchant marine is overwhelmingly oil-burning—our modern navy 
entirely so. 
The problems connected with oil-tight riveting first comes to a head at the cere- 
mony of testing tanks; it will be more or less of a ceremony depending on the excellence 
or otherwise of a series of operations starting before template making and ending with 
riveting and caulking. Service conditions have their say later. 
Mr. Frear’s paper bears evidence of considerable work. I feel somewhat diffident 
in discussing it, having been on the office end of our profession so long that yard problems 
are not as fresh in mind as I would like them to be. In talking it over with some of our 
(New York Shipbuilding Corporation) outside people the following points were sug- 
gested, mostly by them, as being worthy of consideration: 
1. Referring to double versus single bounding bars; in transversely framed ships 
the extra rigidity given by the double bar was worth the extra fitting; in longitudinally 
framed ships, however, the rigidity imparted by the longitudinal frame brackets makes 
the single bar the preferable job, the two-ply riveting advantage being thus obtained. 
2. Another suggestion was made to the effect that for oil work a pan-headed rivet 
with a slight collar formed on the outside at the base of the head would be a good thing, 
so as to enable caulking to be done if found necessary on testing. There is enough 
demand for these rivets to justify special dies for the head. 
3. In many vessels, merchant and naval, we have bunker tanks that are quite deep 
and which consequently demand the best workmanship to ensure tightness. Our naval 
constructors are entitled to credit for their efforts to successfully reconcile the spacing 
for strength with that for tightness. These efforts result generally in wider spacing, 
giving greater strength, less riveting and at the same time satisfactory conditions as to 
tightness. British practice seems to bear this out. 
4. Single-riveted seams for center-line bulkheads referred to on page 65 of the paper 
are something that will be admitted only after considerable discussion. There will be 
times in port when a considerable head will be on the bulkhead with the vessel loading 
and unloading; the upper and lower strakes at least are integral members of the longi- 
tudinal girder requiring rigid connection to the adjacent plates. Also during testing 
of tanks, center-line bulkheads will get heavy unilateral loading. 
5. All efforts to economize and keep down production costs are to the point in 
these days, and it would be interesting to hear from the American Bureau as to their 
experience with single-riveted seams in the upper parts of oil-tight bulkheads as these 
are apparently permitted under their rules (Section 30, sub-section 20, page 88). 
