3. 1: RUDDER
A vertical blade at the stern of a
vessel that can be turned
horizontally to change the vessel's
direction when in motion.
➔Rudder angle is upto 35 degree
➔Trammel gauge( L shaped
instrument) is used for checking
rudder drop
➔
5. Balanced rudder
➔
➔
➔
Open stern frame with
a bottom pin which is a
sopport bolt or pin with
a bearing.
The upper bearing is
inside the hull.
Mainly used in tugs
and single screw
marchant ships.
6. Semi balanced skeg rudder
●
Also known as a
horn rudder or a
marine rudder. The
movable part of the
rudder is supported
by a fixed skeg with
a pindle at the
bottom of the skeg.
7. Full skeg rudder
➔
➔
An unbalanced rudder, the
rudder is supported by a
fixed skeg with a pindle at
bottom.
Applied manily to large
sailing yatches but also
applied as hydro planes
on under water vechicles.
8. Spade rudder
➔
➔
➔
A type of sailboat rudder
that is fastened only to
the rudderpost and not to
the keel or transom.
applied extensively to
single and twin screw
vessels including small
power crafts,yatches,
ferries, warships and
some large marchant
ships.
Also employed as submarines and other under
water vechicles
9. 2: SKEG
●
A brace that
extends from the
rear of the keel to
support the
rudderpost.
10. ➔
A skeg (or skag) is a
sternward extension of the
keel of boats and ships
which have a rudder
mounted on the centre line.
The term also applies to the
lowest point on an outboard
motor
12. stabilizer fins are generally rectangular in shape and
are attached in pair on each side to provide the
necessary balance to the ship. The size of the fins
depends on various factors such as the ship's breadth,
length, displacement etc. However, compared to the
size of the ship, the size of the fins is relatively quite
small.
13. 4:BILGE KEEL
●
●
●
●
It is used to reduce a ship's
tendency to roll.
Bilge keels are employed in pairs
(one for each side of the ship).
A ship may have more than one
bilge keel per side, but this is rare.
Bilge keels increase hydro-dynamics
resistance to rolling, making the ship
roll less.
14. 5:SACRIFICIAL ANODE SYSTEM
●
metallurgy an
electropositive
metal, such as zinc,
that protects a more
important
electronegative part
by corroding when
attacked by
electrolytic action
16. 6:PROPELLER
●
A marine propeller is a propulsion device
which converts the power transmitted from
the engine into a thrust force to propel the
vessel.
17. CHARACTERISTICS
●
●
It consists of a number of
identical twisted blades usually 35 equally spaced arround the hub
or boss. The hub or boss is
mounted on the propeller shaft.
The hub of the propeller is fitted
at one end of the propeller shaft
by means of a nut.
Propeller is made
up of mainly
manganese bronze,
stainless steel and
phosphorus bronze.
18. ●
Pitch of the propeller ;
pitch of the propeller is the apparant
distance moved by the propeller on
its axis on one rotation of the
propeller.
➔TYPES OF PROPELLER
●
Fixed pitch propeller
●
Variable pitch propeller
●
Ducted propeller
●
Skeg propeller
19. ➔
●
●
Fixed pitch propeller
Fixed pitch propeller
has fixed blades which
are integral with the
propeller boss.
The blades are fitted at
an angle which gives a
permanent pitch for the
propeller.
20. Variable pitch propeller
➔
➔
A controllable pitch propeller
(CPP) or variable pitch
propeller is a type of propeller
with blades that can be rotated
around their long axis to
change their pitch.
If the pitch can be set to
negative values, the reversible
propeller can also create
reverse thrust for braking or
going backwards without the
need of changing the direction
of shaft revolutions.
21. ●
●
●
It is provided with
detachable propeller
blades.
The blades are
mounted on a
angular slotted
sliding block house
in a hollow hub.
A pitch control rod is
attached to the
angular block.
22. Ducted propeller
➔
➔
➔
A ducted propeller, also known as
a Kort nozzle, is a propeller fitted
with a non-rotating nozzle.
It is used to improve the efficiency
of the propeller and is especially
used on heavily loaded propellers
or propellers with limited diameter.
which is shaped like a foil,
offers advantages for certain
conditions over bare propellers
.
24. 7:BOW THRUSTER
Bow thrusters are type of propellers, which are
smaller in size and which help in better
maneuverability of the ships at lower speeds. They
are generally used for maneuvering the vessel near
the coastal waters or while entering or leaving a port.
Bow thrusters help in assisting tug boats in berthing
the ship without wasting time.
25. 8:BULBOUS BOW
A bulbous bow is a protruding
bulb at the bow (or front) of a
ship just below the waterline.
The bulb modifies the way the
water flows around the hull,
reducing drag and thus
increasing speed, range,
fuel efficiency, and stability.
