<s>
The	O
Forbes	B-Device
Log	I-Device
is	O
an	O
instrument	O
for	O
measuring	O
the	O
speed	O
and	O
distance	O
traveled	O
by	O
ships	O
,	O
notably	O
those	O
of	O
the	O
Royal	O
Navy	O
.	O
</s>
<s>
They	O
were	O
introduced	O
commercially	O
by	O
Elliott	O
Brothers	O
in	O
1909	O
and	O
were	O
fitted	O
to	O
all	O
capital	O
ships	O
by	O
1912	O
,	O
generally	O
to	O
aid	O
the	O
use	O
of	O
the	O
dumaresq	B-Device
as	O
well	O
as	O
battle	O
reporting	O
.	O
</s>
<s>
Initial	O
tests	O
of	O
the	O
Forbes	B-Device
Log	I-Device
in	O
1912	O
demonstrated	O
it	O
was	O
not	O
entirely	O
accurate	O
,	O
which	O
added	O
to	O
a	O
larger	O
set	O
of	O
problems	O
being	O
encountered	O
by	O
the	O
Navy	O
's	O
new	O
gunlaying	O
instruments	O
.	O
</s>
<s>
These	O
issues	O
were	O
eventually	O
solved	O
,	O
and	O
the	O
Forbes	B-Device
Log	I-Device
remained	O
a	O
standard	O
solution	O
well	O
into	O
World	O
War	O
II	O
,	O
by	O
which	O
time	O
they	O
were	O
found	O
on	O
almost	O
all	O
British	O
and	O
allied	O
ships	O
,	O
including	O
submarines	O
.	O
</s>
<s>
One	O
of	O
the	O
remote	O
outputs	O
of	O
the	O
Forbes	B-Device
Log	I-Device
was	O
placed	O
in	O
the	O
gunnery	O
control	O
rooms	O
where	O
they	O
were	O
initially	O
used	O
to	O
set	O
the	O
dumaresq	B-Device
and	O
range	O
clocks	O
by	O
their	O
respective	O
operators	O
;	O
in	O
the	O
post	O
World	O
War	O
I-era	O
,	O
the	O
system	O
was	O
often	O
automated	O
,	O
eliminating	O
the	O
need	O
for	O
an	O
operator	O
to	O
do	O
this	O
.	O
</s>
<s>
The	O
measuring	O
system	O
of	O
the	O
Forbes	B-Device
Log	I-Device
consists	O
of	O
an	O
L-shaped	O
tube	O
that	O
projects	O
through	O
the	O
hull	O
with	O
the	O
bottom	O
portion	O
of	O
the	O
L	O
facing	O
forward	O
.	O
</s>
<s>
The	O
advantage	O
to	O
the	O
Forbes	B-Device
Log	I-Device
is	O
that	O
the	O
signal	O
can	O
be	O
amplified	O
and	O
sent	O
anywhere	O
in	O
the	O
ship	O
.	O
</s>
