Maritime Related

1. EQUIPMENT FOR CONTROLLING THE
A maritime documentary presented by:
BSMT 3 - Polaris B GROUP 3

2. • To effectively control the movement of a ship
through water depends on her equipment used
for maneuvering. Mainly, the equipment used
for this purpose are the ship's main engine(s),
propeller(s), rudder(s), thruster(s), anchors and
mooring lines. The shiphandler should have the
knowledge on how these equipment operate,
how to use them, of their advantage, as well as
disadvantages.

3. TYPES OF MAIN ENGINES
• Majority of merchant ships now are fitted
with a diesel engine. This type can be
started and stopped. Full power is
developed faster than the steam turbine
engine. However, in reversing there is some
delay when the shipis having a headway
exceeding 6 knots. The headway must first
be reduced before it can be started for
astern movement. This is because of the
strong resistance of water stream on the
blades of the propeller when stopped.
Mai
Eng

6. • The steam turbine must be given time to
increase revolutions so this type is slow to
develop power. It must be completely
stoppped before it can be reversed and this
takes about five minutes which is rather too
long a time when maneuvering in harbor
water. For this reason, there is a separate
smaller turbine that is used for astern power
but provides only 50% or less than ahead
power and very slow responce.
Mai
Eng

8. • A gas turbine does not use steam to run it.
It uses a high-pressure gas produced in a
gasifier that is composed of a combustion
chamber and a compressor.
Mai
Eng

10. THE PROPELLER
• The purpose of the propeller is to convert
the ppower of main engine into thrust
(pushing force.) To do this, the principle of
the scew is used. Just as a screw works
through the wood when turned, similarly the
propeller when it rotates also workds
through the water driving the ship forward or
astern depending on its direction of
revolution (rotation.)
Pro

12. • Diameter - The measurement of two
times the distance from the centerline of
the hub to the tip of one blade of propeller.
Pro

13. • Pitch - The distance a propeller or the ship
would advance after one complete revolution
of the propeller if it is going through a solid
substance, just like a scew going through
wood. The average value of the pitch in
ordinary propeller designs is 1.2 to 1.4 of the
propeller diameter.
Pro

14. • Slip - the difference between the distance a
propeller should travel and the distance it
actually travels in one complete revolution. It
is expressed in percentage.
• Propeller Speed - the speed in miles per
hour traveled by the tips of the rotating
blades.
Pro

15. • Cavitation occurs under certain conditions
during the rotation of propeller wherein
cavities (bubbles) are formed in contact with
the propeller blades reducing its thrust and
thereby, reducing the ship's speed. This
occurs when the propeller is rotating
excessive speed in rough seas.
Pro

18. How to solve for engine speed:
)(1852),(6080
60
mft
PitchRPM
dEngineSpee
××
=
Pro

19. • Apparent Slip is the difference between
the stream projected by the propeller and
the speed of the ship, in relation to a fixed
point in the water, clear of the wake.
• A right-handed propeller is one that
rotates clockwise when going ahead and
counterclockwise when going astern facing
forward.
• A left-handed propeller rotates
counterclockwise when going ahead and
clockwise when going astern facing forward.
Pro

20. • A controllable pitch propeller, also
known as variable pitch propeller, has
blades that are adjustable. The engine is
kept running at a predetermined RPM and
constant direction. By adjusting the pitch of
the blades the speed of the ship could be
increased or decreased or stopped and also
for astern movement without reversing the
direction or rotation of the propeller.
Pro

22. • Voith Schneider is a special type of
propeller fitted to small vessels such as
harbor tugs or salvaged boats makes the
vessels highly maneuverable. It is not like
the above-described propellers that operate
like screw.
Pro

23. VORTH SCHNEIDER PROPELLER

24. • A Kort Nozzle propeller is the same as the
fixed-pitch propeller but it is fitted inside a
duct.
Pro

25. • The thrust of the propeller blades has two
components (parts): a fore-and-aft one and
a small arthwatships one. The fore-and-aft
component is the force that moves the ship
forward ans the arthwatships one is the
force that drives the stern of the ship
through the water in a direction at right
angles to the ship's line of motion. This is
also known as transverse thrust. When
going ahead from the dead in the water, the
bow of the ship will cant (turn) to port as the
headway becomes faster, the swing of the
bow decreases and may change to
starboard.
Pro

26. • When going astern from the dead in the
water, the bow of the stern cants strongly to
port and continues to do so when the ship
gains sternway until the rudder is used to
slow down a little by putting it to hard right.
Pro

27. THE RUDDER
• The rudder is a device used for steering
(directing the course) and manuevering the
ship. In certain manervers it can be used to
slow down the ship. The three types of
rudders are old-fashioned, balanced or
semi-balanced and the active rudder.
Rud

28. • The old-fashioned rudder has all its face
area abaft the turning axis (rudder post.)
Rud

29. • The balanced or semi-balanced rudder
has about 30%of the face area forward of the
turning axis. This type requires less powerto
turn it because when it is turned while the ship
is moving ahead the water stream strikes the
forward area and helps turn the rudder.
Rud

30. • The active rudder is like an old-
fashioned rudder but has a propeller
driven by asubmerged electric motor
fitted at the outer edge of the rudder.
Rud

31. • When the propeller is turning for ahead
movement it produces a slipstream
(discharge current) flowing astern. If the
rudder is put over to one side, say to
starboard, the force of the slipstream strikes
the face area of the rudder producing a
transverse thrust that pushes the stern to
port causing the ship to turn on its pivot
point and turning the bow to starboard. The
Bernoulli's effect also explains the rudder
movement as follows: The rudder's
amidships side are curved slightly outwards.
Therfore, the flow of water speeds up slighly
over the rudder surface thereby causing a
slightly lower pressure.
Rud

32. • When the rudder is moved to one side, the
pressure is lower on one side than the other,
creating a lift. There is also a force called
drag which tends to slow the vessel down.
The resultant of these two forces will be the
direction of movement of the rudder and the
bow will go the opposite way. If you want to
turn the ship to port, then turn the helm to
port. Except for any active rudder, the
rudder can be turned to a maximum angle of
45 degrees either side but it may stall (get
stuck) when the ship is at full ahead. An
angle of 35 degrees is considered to have
maximum effect.
Rud

33. SIDE THRUSTERS
• The equipment for manuevering a ship, that
is, the propeller and rudder, are all situated
at the stern to propel and steer the ship.
These equipments can move the bow
sideways but a longitudinal motion
accompanies it. Some ships are fitted with a
device near the bow canned bow thruster
to give the forward end of the ship a lateral
thrust when needed without necessarily
gicing the ship a forward motion.
Side
Thr

35. ORDERS TO THE HELM AND
ENGINE ORDER TELEGRAPH
AND BOW THRUSTER
• During maneuvers for berthing or
unberthing, or other occasions when the
rudder and engine are used in various
orders are given to the helmsman, engine
order telegraph and bow thruster cotrol
operators. Orders must be given firmly and
clearly, and should be repeated by the perso
to whom the order is directed in the exact
words given.
Ord

36. Examples:
1. "RIGHT (LEFT) 10° RUDDER". The wheel is
turned to the right (left) until rudder indicator
shows 10° to the right (left.)
2. "RIGHT (LEFT) FULL RUDDER". The wheel
is turned to the right (left) until rudder
indicator shows 35°.
3. "RUDDER AMIDSHIPS". The rudder is
brought to the amidships position. This is to
allow down the swing of the bow and is a
warning that the new course or heading is
being approached.
Ord

37. 4. "STEADY" or "STEADY AS SHE GOES". At
this order the helmsman should keep the
ship on the heading she has at that instant
by manipulating the wheelas required, and
reports "NOW STEADY ON _______° SIR".
5. "MEET HER". The rudder is brought up to
the other side about 10° in order to stop the
swing of the bow.
6. "SHIFT THE RUDDER". Change the
position of the rudder from right to left, or
vice versa at the same number of degrees.
Ord

38. 7. "NOTHING TO THE RIGHT (LEFT)". The
Helmsman should keep all small variations
in steering to the right (left) of the compass
course. This is often given when the ship is
being affected by wind or current.
All commands to the helmsman in regard to
the course refer to the compass by which he
is steering and should be given in three
digits. Example: "COURSE, ZERO, NINE,
FIVE". After accomplishing an order the
helsman should report it, as for example,
"RIGHT 10° RUDDER NOW, SIR." The
correct acknowledgment to any report by the
helmsman should be "VERY WELL."
Ord

39. • Order given to the engine room telegraph
operator.
When going to use the engines, the first
order given i: "STAND BY ENGINE(s)". At
this command the operator repeats the
order and puts the handle or pointer of the
instrument to Stand-By poisiton. Orders that
follow are given in three parts:
1. The first part designate which engine is
referred to as STARBOARD (PORT)
ENGINE or ALL ENGINE. This alerts the
operator.
Ord

40. 2. The second part of the order refers to the
direction in which the telegraph
handle/pointer should be moved, as
"AHEAD" or "ASTERN".
3. The third part gives the speed at which
the engines be run.
Example: When the order "PORT ENGINE
ASTERN SLOW" is given, the operator
repeats and at the same time rings up the
telegraph on the engine order telegraph then
reports "PORT ENGINE ASTERN SLOW,
SIR."
Ord

41. • Order to the Bow Thruster control operator:
Orders given should also be repeated word
for word by the operator before executing it.
The order given is, first in which direction the
bow of the ship should be followed by the
speed, as for example: "BOW THRUSTER
TO STARBOARD SLOW?"
Ord

42. SUMMARY
The power to move the ship is generated by
the main engine. By applying the principle
of screw, the power from the main engine is
converted by the propeller into thrust in
order to propel the ship through water. The
rudder is the device that steers or guides
the ship to the direction that the shiphandler
wants the ship to go. Bow thrusters
provide means to move the ship's bow
especially when berthing or unberthing.
Standard commands to the helmsman,
operator of the engine order telegraph and
bow thruster control should be used and the
correct reply to the orders should be
observed.

43. FinPREPARED BY:
JARQUEO, Roden
LAPASTORA, Arvy
LORAEZ, Victor Allan
MATA, Martin Vale
MALLARI, Daniel