DENSITY OF SMOKE METHOD ON U.S. S. CONYNGHAM. 3 
Captain A. P. Nistack, Vice-President :—This device is more important than at first 
sight appears. Destroyers in our Navy are not only required to run smokeless in competi- 
tive tests for engineering efficiency, but are, at times, required to make all the smoke pos- 
sible in order to “screen” tactical movements. The usual method of communicating from 
the bridge to the fire rooms is by four different telltales, whereby the officer of the deck 
controls the character of the smoke from each one of the four stacks by communicating 
with the firemen controlling the boilers which use them. This requires more or less con- 
stant supervision and signalling. By the method here described, the fireman may himself 
keep informed of what his fires are doing as to smoke. 
The use of smoke as a “screen” has a very definite advantage and purpose at certain 
times, and this device works both ways, not only to aid in determining how little smoke, but 
how much smoke is being emitted from the stacks. 
REAR ADMIRAL HALL (Communicated) —-This device makes it possible to determine the 
character of smoke at the base of the stack and to regulate the fires for maximum efficiency. 
Combustion is more completely and easily governed by observing smoke control than 
by observing flue gas analysis. 
The following data, taken from a test on a Babcock and Wilcox boiler, the stack from 
which was fitted wih mirrors for determining the character of the smoke, show compari- 
son made with smoke charts :— 
Test No. 3. Test No. 4. Test No. 5. Test No. 6. 
(Cle a 6 ote. Atala cBeerao elses es EVE Rats yb eaeD Moa i tue Sule era 11.57 11.86 10.71 10.94 
CO a cd oleio Cietale chard © ARROIGIE CRSA Ere ic Retest gi eran nn Serna 04 04 02 .00 
(SSB Sig F Sh SESS weeterdtat & rau eee eo ker eae er eee Rane re arti 4.50 4.08 5.18 4.73 
IPSS gy WR SI eet eae ap Re Re 83.89 84.02 84.09 84.33 
Samal > wi db RES Se hal Wale Bren Be eae pte ans 1.3 1.5 2.3 1.15 
Dieiemmen oundyon (Olen hy: te cci te cath chr des wlalactuee ¢ 15.72 15.86 14.12 15.44 
GilenmeniGlenGye neti tse sere Elenco kay vee) S Akal: 79.50 80.21 71.41 78.08 
@ilsburned per hour (pounds). 2.2.5.2... ee ee tae 1,202 666 1,922 1,947 
In tests 3, 4 and 6, control of fires depended on the character of the smoke and was 
kept practically constant. In test 5 control of fires was dependent on gas analysis. 
In tests 5 and 6 the amount of oil burned was approximately the same. The follow- 
ing are comparative results in favor of smoke control over gas analysis control :— 
Test No. 5. Test No. 6. 
Rounds: olvbumed pen Nout. ac.geeekice eh as salem e da eile nee severe ne 1,922 1,947 
Metemevaporated: per pound Of Oil Zit ee sles ie os leie es 2 de ape cee see ole) ace 14.12 15.44 
Ensile GEchicreneygl (PER ICeMb) err teeta ass we ki)e ese tihe coun camila se 71.41 78.08 
Gain in boiler efficiency by smoke control (percent) ................... «2... 6.67 
THE PRESIDENT :—On behalf of the Society, I will extend thanks to Rear Admiral Hall 
for this interesting paper. 
We will now take up paper No. 2, entitled, “Salvage Equipment Used in Raising Sub- 
marine F-4,” by Naval Constructor J. A. Furer, U. S. Navy, Member. 
Naval Constructor Furer presented the paper. 
