navy gator
TRANSCRIPT
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NAVYGATOR
Any navygator vessel can be said to be made up of 4 primary parts:
• A floating structure: HULL
• An energy
source:
POWER
PLANT
• A thrust system: PROPULSION
• A control mechanism: RUDDER
Now let us see them in detail.
HULL
A hull is the watertight body of the vessel. Its primary duty is to provide a waterproof platform to
other components of the vessel. The structure of the hull varies depending on the vessel type. In a
typical modern steel ship, the structure consists of watertight and non‐tight decks, major transverse
and longitudinal
members
called
watertight
bulkheads,
intermediate
members
such
as
girders,
stringers and webs, and minor members called ordinary transverse frames, frames, or longitudinals,
depending on the structural arrangement. The uppermost continuous deck may be called the "upper
deck," "weather deck," "spar deck," "main deck" or simply "deck." The particular name given
depends on the context‐‐the type of ship or boat, the arrangement, or even the area where it sails.
Coming back to our problem, “We require a stable floating structure within the prescribed
dimensions!” This can be achieved in many ways.
• Plastic bottles: They can be cut symmetrically to provide a stable hull.
• Ply wood
along
with
inflated
cycle
tube:
Ply
wood
normally
has
the
tendency
to
sink
(depending on the size) this can be solved by means of inflated cycle tubes. The ply wood
provides superior strength over plastic without loss of buoyancy.
• Sheet metal: Sheet metal when turned into a hull form as shown below provides excellent
strength and stability. Note that slight variations from the hull form can lead to loss of
buoyancy thus floatation is achievable only by means of rigorous experimentation involving
CAD or trial and error techniques.
• Other alternatives include wooden hull, talcum powder tins etc.
Make your hull leak‐proof as leakages reduce your points. This can be done using “M Seal”, “Dr Fix
it” etc.
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POWER‐PLANT
This is the primary energy source of your vessel. We have made it clear in the rules that no power
supply will be provided in the arena. Note that charging slots will be provided on request.
In the
present
scenario,
power
plant
primarily
refers
to
an
electrical
energy
storage
device
popularly
known as battery. As we haven’t made any restriction on the number, voltage, ampere‐hours etc.
you are free to choose any suitable battery. Some of the common varieties available in the market
are
• In the case of R/C vessels go for lighter ones as the battery has to be mounted on the vessel.
• In the wired vessels you have two options:
o Battery mounted on the vessel with external control (Joy stick).This one increases
the stability of the model, no more worries on toppling!
o External Battery as well as external control (Joy stick). This one reduces the weight
of the
vessel
considerably
thereby
making
it
swift!
PROPULSION
Propulsion systems mainly consists of fluid thrusters that pushes the fluid backwards, hence the
reaction force moves it forward. The most common system is the engine + fluid contact device. The
engine here can be a DC electric motor of a suitable rpm. The fluid contact device can be rotatory as
in paddle‐wheels, propellers or reciprocating as in rows, flap etc.
• Propellers: There are many variations of marine propeller systems, including twin, contra‐
rotating, controllable‐pitch, and nozzle‐style propellers. Smaller vessels tend to have a single
propeller. Power
is
transmitted
from
the
engine
to
the
propeller
by
way
of
a propeller
shaft,
which may or may not be connected to a gearbox. DC motors of fixed rpm like 75, 100, 200,
which has in built gear trains, which are readily available in the market, can be used.
• The paddle wheel: They are generally built of a strong frame work, upon the outer edge of
which are fitted numerous paddle blades (called floats or buckets). The bottom quarter or so
of the wheel travels underwater. Rotation of the paddle wheel produces thrust, forward or
backward as required. More advanced paddle wheel designs have featured feathering
methods that keep each paddle blade oriented closer to vertical while it is in the water; this
increases efficiency. The upper part of a paddle wheel is normally enclosed in a paddle box
to
minimise
splashing.
• Rows & Flaps: The rotating motion of a motor can be converted into reciprocating by
providing an eccentric disc. Rows or Flaps connected to the end of this acts as a thruster.
TIP: CPU cooler fans can be converted into excellent propulsion systems!
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RUDDERS
As the track is not a straight one steering the vessel plays a crucial part in the event. Direction
control can be achieved in any of the following ways:
Single Propeller:
• Rudders can be used to alter the direction of fluid flow thus changing the direction of the
vessel.
Double Propeller:
If you are using 2 propellers on either side of your vessel, alternate powering of the propellers will
enable you to change the course of your vessel. That is left‐ on right‐off will turn your vessel to the
right and
vice
versa.
Multi Propeller:
Additional propellers apart from the main thruster can be provided on the sides of the vessels to
enable control capabilities.
Other Useful Resources
http://www.wonderhowto.com/how‐
to‐
make‐
remote‐
controlled‐
engine‐
boat‐
from‐
useless‐
crap‐
176861/