<s>
The	O
Vickers	B-Device
Range	I-Device
Clock	I-Device
was	O
a	O
clockwork	O
device	O
used	O
by	O
the	O
Royal	O
Navy	O
for	O
continuously	O
calculating	O
the	O
range	O
to	O
an	O
enemy	O
ship	O
.	O
</s>
<s>
This	O
was	O
calculated	O
by	O
other	O
means	O
,	O
often	O
by	O
use	O
of	O
a	O
Dumaresq	B-Device
or	O
a	O
time-and-range	O
plot	O
.	O
</s>
<s>
An	O
important	O
aspect	O
of	O
the	O
Vickers	B-Device
range	I-Device
clock	I-Device
,	O
as	O
well	O
as	O
other	O
designs	O
using	O
a	O
wheel-on-disc	O
drive	O
for	O
the	O
variable	O
speed	O
motor	O
,	O
such	O
as	O
the	O
electrical	O
clock	O
used	O
in	O
the	O
Dreyer	O
Fire	O
Control	O
Table	O
,	O
was	O
that	O
it	O
could	O
only	O
generate	O
ranges	O
according	O
to	O
a	O
constant	O
range	O
rate	O
.	O
</s>
