NOTES ON RIVETS AND SPACING OF RIVETS FOR OIL-TIGHT WORK. 
By Huco P. Frear, Eso., MEMBER. 
[Read at the twenty-eighth general meeting of the Society of Naval Architects and Marine Engineers, held in New 
York, November 11 and 12, 1920.] 
It is improbable that the writer would have selected the above subject, which 
was assigned to him, had he volunteered to submit a paper at this session. The 
secretary usually sends out notices at an early date inviting members to recom- 
mend subjects and authors, and ‘Rivets and Spacing of Rivets for Oil-Tight 
Work’’ appears to be one of the topics which attracted the attention of the 
Council. An exhaustive treatment would be largely a matter of compilation and 
beyond the scope of this paper and will not be attempted, it being the desire 
rather to invite discussion if there is a difference of opinion regarding general 
practice or on the few points raised, without which the paper will be of compara- 
tively little value. 
The present high state of efficiency of the modern tanker leaves little to be 
said on rivets and rivet spacing for oil-tight work that would be both new and 
conservative, and it may be safely said that radical departures from the practice 
arrived at as the result of years of experience would invite trouble. 
Riveting is unquestionably one of the greatest, if not the greatest, item of 
expense entering into the cost of construction, and the unprecedented demand for 
tankers and oil-burning vessels at this time magnifies its importance. 
Experience has become much more general in both the building and operating 
of tankers, and perhaps this was thought to be an opportune time to provoke dis- 
cussion along other than traditional lines. 
Rivets and spacing of rivets for oil-tight work, as covered by the Classifi- 
cation Rules, Navy Department, British Admiralty, etc., do not vary radically 
although, on account of higher stresses used, a greater spacing is adopted in some 
parts for naval vessels. It must be borne in mind, however, that naval vessels are 
not subject to the great variations in load encountered in the merchant marine, 
and therefore the stresses can be anticipated with greater accuracy. 
Rules for rivets and rivet spacing are the result of evolution arrived at by 
rule of thumb, experience, size of rivet found practicable to drive, spacing suitable 
for caulking, experiments, calculations, survey reports on damage cases, etc., and 
are in the opinion of the writer generally satisfactory with very few exceptions, 
which will be referred to later. 
Oil tightness depends, perhaps, more on good workmanship than any other 
one thing, especially so far as riveting is concerned. If every rivet could be guar- 
anteed 100 per cent perfect, slightly greater spacing would be practicable and 
might be allowed by classification societies except where a given efficiency of joint 
