Page 215 - Introduction to Marine Engineering

198 Deck machinery and hull equipment

Observation
Exterior
Sea anchor-
Interior
light
Rescue line
and quoit Topping-up/deflation
valve (arch)
Rainwater collector
tube
Outer entrance
cover

Topping-up
deflation
wive
WJoor)

Topping-up
deflation
valves
chambers)

Drawstring bag
{emergency pack)
Deflation
Inflation hose
assembly _ . , x Lifeline port
Operating \ \
head < Stabilizing
CO 2 cylinder pocket
Figure 10.14 Liferaft

Whistle
International regulations require audible signals to be made by a ship in
conditions of poor visibility. The ship's whistle is provided and arranged
to give prolonged blasts at timed intervals when operated by a hand
control.
One type of air-operated whistle is shown in Figure 10.15. The
compressed air acting on the diaphragm causes it to vibrate and the
sound waves are amplified in the horn. The control system associated
with the whistle can provide whistle operation as long as any of the
operating switches is in the 'on' position. Alternatively short blasts can be
given by on-off operation, since instantaneous cut-off occurs after each
blast. A more sophisticated control system incorporates timing gear
which provides a prolonged blast every two minutes, or other