Liquid compass. There are replaced parts in an envelope marked ACO0217.1 which can be found via the Whole/Part toggle.
Bowl: Aluminium painted black inside white. Filler plug and lifter mechanism at side. Glazed top and bottom. Conical in shape, the bottom being longer in diameter (7.8") than the verge (5.0"). Verge ring has scribed lubber line and is fitted with a red pointed hinged sight and sliding pointer. Mounted in gimbals which are attached to a U-shaped bracket by two lubber discs, to dampen out vibrations.
Card: White painted float 2.5" diameter. Has a movable arow mounted to it. A lever operated by the lifter engages with a central log wheel; this lifts the float and the cogs engage on four studs attached to the moveable portion of the central boss, attached to verge glass, engage in holes in the centre of arrow, enabling it to be set to any required direction by means of a milled knob set in verge glass.
Needle: Two needles mounted either side of float.
Pivot: Inverted type, with brass stem attached at centre of glass at base of bowl.
On ACO stand Dimensions: 10.25" x 11.75" (26cm x 29.9cm) O.A. Height 10.75" (27.3cm)