156 RECENT ADVANCE IN OIL BURNING. 
There are many reasons for this. In the first place a large number of vessels 
now burning oil were originally designed for coal, and in others, which were designed 
to burn oil, the old proportions applying to the coal-burning ships have been adhered 
to, in many instances probably because it is feared that a return to coal fuel may 
some day become necessary. Furthermore, in the large majority of instances the 
vessels are fitted with Scotch boilers, and the above figures mark practically the 
limit to which such boilers may be forced with safety. The same statement will 
apply also to water-tube boilers until such time as more consideration is given to 
the type of condensers and the size and design of evaporators. 
In marked contrast to the merchant marine, the Navy Department is making 
rapid advance of a most important character. It is now using water-tube boilers 
entirely in fighting ships, with improved condensers and evaporators. Boilers 
are being constructed containing more than 11,000 square feet of heating surface, 
while in the matter of size and capacity of oil burners, within the last few weeks 
successful tests have been run at the Fuel Oil Testing Plant at the Philadelphia 
Navy Yard in which more than one ton of oil was atomized per hour in the indi- 
vidual burners. 
If then, as I believe, the work of the Navy is a forecast of what will eventually 
be the trend of development in the merchant marine, not only will considerable 
improvement be made in oil-burning equipment, but the Scotch boiler, with its 
enormous weight, poor circulation and unsuitability to high pressure, will become 
a thing of the past. This type of boiler has long been tottering on its last support 
of prejudice and the reactionary belief that it is impossible to keep salt water out 
of the feed system. We shall have, in its place, large, safe, light, economical 
water-tube boilers, installed in closed fire-rooms, burning oil and operating under 
forced draft with a few large-unit mechanical atomizers. 
The remarkable economy of the properly designed small tube express-type 
water-tube boiler at high rates of forcing with oil fires was demonstrated not very 
long ago in some notable tests at the Fuel Oil Testing Plant. The tests were con- 
ducted under the direction of Lieut. Commanders A. M. Penn and W. R. Purnell, 
U.S. Navy, and their staff of trained assistants. The boiler was of the White- 
Forster design, built by The Babcock and Wilcox Company, and contained 7,565 
square feet of heating surface and 753 square feet of superheating surface, the fur- 
nace volume being 751 cubic feet. Three different types of air registers were 
used:—the Bureau of Engineering forced-draft design (of which there were sixteen 
units installed), the Bureau of Engineering natural-forced-draft design (eleven 
units), and what was then known as the Peabody register manufactured by The 
Babcock and Wilcox Company, designed for either forced or natural draught and 
of which there were also eleven units. All three registers were tested successively 
with bureau burners. Final tests were then made with Peabody burners with 
Peabody air registers only.* 
*This equipment is now designated as The Babcock and Wilcox Air Register and The Babcock and Wilcox 
Mechanical Atomizer. 
