248 HEAVY-OIL, ENGINES FOR MARINE PROPULSION. 
anchored at top and bottom, provides with the smallest amount of material and 
weight the necessary resistance to the stresses in the most direct and efficient form. 
I believe that the designers of marine engines should attempt as much as 
possible to cut loose from stationary types, and to go back to what we call the 
standard marine type, which is being represented best in the torpedo boat engine. 
The starting is also a question that with Diesel engines has proved quite difficult, and 
this is due to trying to use the injection air at a pressure of 750 to 900 pounds per 
square inch for starting purposes. That means a very short discharge enters 
the cylinder at the beginning of the stroke, and then by its own expansion, gives 
the impulse to the piston for the farther movement down. I believe it would be 
found far more convenient and efficient to provide air at a lower pressure from the 
second stage—I believe 150 or 200 pound pressure would be far superior. The 
starting valves to be operated by some special form of alink, by which they could be 
cut in or cut out at the will of the engineer and by which they would have a late 
cut-off and a long stroke for receiving air from the reservoirs under full pressure. 
By this we have a much wider range for the starting and can do with less cylinders 
in this way than we would be obliged to have when we use the injection air at a high 
pressure during only a short part of the stroke. 
I believe that double-acting engines with hollow piston rods and oil cooling 
can be provided in such mechanical perfection that there will be absolutely no 
difficulty experienced on the part of any good steam engineer with large marine 
practice. He would be prepared to handle it to best advantage. 
In Germany at the present time a great many experiments are made with wood 
tar and gas tar, and all kinds of substitutes for fuel oil. All refuse of oil distillation 
canbe used almost withentire satisfaction in Diesel engines, provided a small amount 
of warming is furnished, which is always available on board ship. 
As to auxiliaries, I have developed a plan for providing a complete compressed 
air plant for distribution to all auxiliaries. I believe that everything could be done 
with compressed air to good advantage, and it would not be necessary to provide 
any special thing in the line of electric auxiliaries, except as they are needed for 
lighting purposes. I believe the modern turbine practice has shown that for rota- 
ting motors compressed air could be used in airjturbines to good advantage and under 
quite good economy; at least the fans and centrifugal pumps could be supplied by 
compressed air turbines. The main thing is that the compressed air in this form 
would be less liable to freezing, and would be much more efficient and serviceable. 
It is also possible to use pre-heating with the compressed air, readily affording 
the means to keep the freezing down and similar difficulties out of the way. It is 
also possible, I believe, in the form of the through-flow engine type which is occupy- 
ing the attention of many engineers, to provide a high compression air engine that 
would compress the airto such degrees of temperature again that no freezing at any 
stage of the operation need take place in the cylinders. Such an air engine would be 
entirely alike to and ‘compare well with the steam engine as far as handiness is 
concerned, and would be far superior to it in that it has no condensation losses. 
a a 
