NOTES ON RIVETS AND SPACING OF RIVETS FOR OIL-TIGHT WORK. 79 
ANGLES TO PLATES. 
Angles less than 3/8 inch thick, 41% diameters. 
Angles 3/8 inch thick and over, 5 diameters. 
The navy yard, New York, proposed to use 6-diameter spacing for connecting 
the transverse bulkheads to the torpedo bulkheads in order to avoid the necessity of 
compensating liners. The bureau approved this proposal, but, to verify the safety of 
this spacing, directed that a test tank be constructed, representative of the structure 
in question, and tested under pressure. Plates 26 to 30 show the scantlings, riveting 
and other details of this tank. 
The tank was subject to a 65-foot water-pressure head and made tight. No trouble 
whatever was experienced in making tight the riveting or caulking of the T-bar stiffeners 
and transverse oil-tight bulkheads in way of 6-diameter rivet spacing. 
Upon completion of the water test, the tank was subjected to a continuous twenty- 
four-hour endurance test with oil at a pressure head of 65 feet. No leaks developed in 
the caulking or riveting in way of the 6-diameter rivet spacing. 
After the completion of the above test, the tank was tested to 38 pounds per square 
inch. This pressure was maintained for four hours, during which period no leaks devel- 
oped. This excess pressure head, equivalent to about 93 feet, was applied only to deter- 
mine if leaks would develop after considerable increase in pressure. 
In order to determine the advisability of adopting some of the suggestions made by 
the various building yards and in order to clear up the doubtful points and, further, to 
obtain data based upon actual test to be used in connection with the revision of the 
bureau’s “‘Specification for Riveting,’ a second test tank was constructed at the navy 
yard, New York, and tested. Plate 31 shows this tank in detail. The report of this test 
is given in full as follows:— 
“Tank was divided by a bulkhead, the two sections being designated (A) and (B), 
the former being the section which has a seam on the 15-pound plating double strapped. 
The sides of this tank are constructed with four different weights of plating; namely, 12, 
15, 20 and 25 pounds. The water pressure was applied to the tank, and everything 
remained tight until the pressure was raised above 10 pounds, when the 12-pound plating 
began to deflect, causing the butt caulking in the seam to leak. It was not possible to 
make this seam tight, and it was decided to continue the test under those conditions. 
‘“SECTION (a). 
“Water pressure was gradually applied to this section of the tank up to 10 pounds, 
at which pressure the tank was perfectly tight. Pressure was gradually raised. The 
seam in the r2-pound plating began leaking at 12 pounds and continued to leak as the 
pressure was raised to 30 pounds. The water supply was then cut off for one hour, dur- 
ing which time the pressure dropped 214 pounds, the leakage being entirely through the 
butt caulking in the 12-pound plating seam; electric welding and other connections were 
perfectly tight during this test. The leakage amounted to % gallon. The only appre- 
ciable deflection was in the 12-pound side of the tank, which deflected 34 inch and left 
a permanent set of 144 inch after pressure was removed. 
““SECTION (B). 
“The pressure on this section of the tank was applied similar to the method used on 
section (A), the result being about the same except that the butt caulking in the seam of 
