<s>
The	O
Fuze	B-Device
Keeping	I-Device
Clock	I-Device
(	O
FKC	O
)	O
was	O
a	O
simplified	O
version	O
of	O
the	O
Royal	O
Navy	O
's	O
High	B-Device
Angle	I-Device
Control	I-Device
System	I-Device
analogue	O
fire	B-Application
control	I-Application
computer	I-Application
.	O
</s>
<s>
It	O
first	O
appeared	O
as	O
the	O
FKC	O
MkII	O
in	O
destroyers	B-Application
of	O
the	O
1938	O
,	O
while	O
later	O
variants	O
were	O
used	O
on	O
sloops	O
,	O
frigates	O
,	O
destroyers	B-Application
,	O
aircraft	O
carriers	O
and	O
several	O
cruisers	O
.	O
</s>
<s>
The	O
FKC	O
MkII	O
was	O
a	O
non-tachymetric	O
anti-aircraft	O
fire	B-Application
control	I-Application
computer	I-Application
.	O
</s>
<s>
Type	O
285	O
radar	B-Application
was	O
an	O
early	O
addition	O
to	O
the	O
FKC	O
system	O
,	O
being	O
fitted	O
on	O
new	O
destroyers	B-Application
from	O
mid-1941	O
onward	O
,	O
and	O
retrofitted	O
to	O
existing	O
destroyers	B-Application
as	O
time	O
and	O
opportunity	O
permitted	O
.	O
</s>
<s>
Later	O
variants	O
increased	O
the	O
maximum	O
target	O
speed	O
to	O
,	O
and	O
were	O
combined	O
with	O
Gyro	B-Device
Rate	I-Device
Units	I-Device
(	O
GRU	O
)	O
which	O
gave	O
tachometric	O
capabilities	O
to	O
the	O
system	O
,	O
and	O
radar	B-Application
which	O
greatly	O
improved	O
ranging	O
and	O
rate	O
keeping	O
accuracy	O
.	O
</s>
<s>
The	O
FKC	O
saw	O
extensive	O
use	O
during	O
the	O
war	O
on	O
British	O
Commonwealth	O
naval	O
ships	O
,	O
typically	O
on	O
destroyers	B-Application
and	O
sloops	O
.	O
</s>
<s>
Prior	O
to	O
the	O
widespread	O
use	O
of	O
radar	B-Application
,	O
optical	O
detection	O
and	O
ranging	O
on	O
high	O
altitude	O
aerial	O
targets	O
was	O
a	O
daunting	O
task	O
,	O
as	O
shown	O
by	O
'	O
s	O
Report	O
of	O
Proceedings	O
,	O
for	O
3	O
September	O
1940	O
:	O
</s>
<s>
The	O
FKC	O
was	O
used	O
throughout	O
the	O
war	O
and	O
its	O
effectiveness	O
was	O
increased	O
by	O
the	O
use	O
of	O
radar	B-Application
for	O
gunnery	O
and	O
to	O
provide	O
warning	O
against	O
surprise	O
attack	O
,	O
as	O
demonstrated	O
by	O
this	O
account	O
of	O
bringing	O
down	O
a	O
Japanese	O
A6M	O
Zero	O
fighter	O
aircraft	O
(	O
a	O
"	O
HAMP	O
"	O
)	O
,	O
in	O
1944	O
:	O
</s>
