From these dimensions I prepared a second
diagram representing the steam power, and when placed in position it
will show at a glance how much space this apparatus will occupy. The
total length lost in this way amounts to 12 feet, leaving for testing
capacity only 15 feet, while that of the electric launch is 27 feet
on each side of the boat; thus the accommodation is as fifteen to
twenty-seven, or as twenty-two passengers to forty, in favor of the
electric launch.
Comparing the relative weights of the steam power and the electric power
for this launch, we find that they are nearly equal--each approaches 50
cwt; but in the case of the steam launch we include 10 cwt. of coals,
which can be stowed into the bunkers, and which allow fifteen hours
continuous steaming, whereas the electric energy stored up will only
give us seven and a half hours with perfect safety.
I have here allowed 8 lb. of coal per indicated horse power per hour,
and 10 horse power giving off 7 mechanical horse power on the screw
shaft; this is an example of an average launch engine.
Pages:
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40