162	NICHOLLS'S SEAMAN^CP  AND NAUTICAL KNOWLEDGE
is made by putting the helm amidships and raising the hand lever at
the side. The liquid throughout the system is then hiought into free
communication by means of a bye-pass valve and the pressure automati-
cally equalises itself. (3) The cylinders are vertical as shown by the
transverse section (Figure 26). The motion of the steering wheel shaft is
transmitted by a rack and pinion gear to the rams, causing the
latter to move up and down in the cylinder according to the
direction in which the hand wheel is turned from the amidships position.
In the diagram of the pipe system connecting the steering telemotor
to the motor telemotor the arrows indicate the circulation of the oil
from the charging tank and back again when charging and testing the
pipe line.
To Replenish the System.—
 1.	Disconnect pipes B and C at the steering wheel and connect
temporarily the spare part BO, called the wash-out piece.
 2.	Fill the charging tank with the hydraulic oil which forms a
gravity feed to the hand pump.
 3.	Disconnect pipe A at valve D, put the end of the pipe into a
bucket, work the pump and pass some oil through the pipe.   The flow
being satisfactory connect up pipe A again.
A. Open charging valves D and E9 also liquid saving valves F and G.
Disconnect pipe C at valve G and put a bucket under the end of it.
Continue pumping. The oil will then flow from the pump through the
pipes A, B and G in succession and pass into the bucket. Keep pumping
for a little time to get a steady flow of oil, thus proving that the pipe line
is quite clear. Keep pouring oil into the charging tank at intervals
to ensure that air is not being pumped into the pipes.
5. Disconnect pipes BG from the wash-out piece and connect to the
steering telemotor.
To Charge the System.—
The Steering Telemotor.—Put the wheel amidships and open the
by-pass by raising the hand lever. Open valve J. «Pump until the oil
rises in the replenishing tank to the level mark on the gauge glass. Close
valve /. Release air at air cocks on the pressure gauge pipes.
The Motor Telemotor.—Release air at ail cocks K on the motor
cylinders and continue pumping until for each stroke of the pump a
rush of liquid comes from the return pipe H. Close charging valve B,
then charging valve D. Open valve J at the steering telemotor (this
valve should only be closed when charging the system). Release the
safety by-pass hand lever. The telemotor is now ready for working*