元となった辞書の項目
ballast tank
noun
One
of
several
external
or
internal
tanks
fitted
in
submarines;
when
filled
with
seawater
they
allow
the
boat
to
submerge;
when
emptied
using
compressed
air
buoyancy
is
restored
and
the
vessel
rises
towards
the
surface.
Auxiliary
ballast
tanks
within
the
pressure
hull
allow
the
submarine
to
be
trimmed.
意味（1）
One
of
several
external
or
internal
tanks
fitted
in
submarines;
when
filled
with
seawater
they
allow
the
boat
to
submerge;
when
emptied
using
compressed
air
buoyancy
is
restored
and
the
vessel
rises
towards
the
surface.
Auxiliary
ballast
tanks
within
the
pressure
hull
allow
the
submarine
to
be
trimmed.
