Ship modelling - 2

Types of models and competitions

Why ship is floating

• An object floats when the buoyant force is large enough to counter the object’s weight
• The air inside the ship which have less density than water that sheep keep it floating
• Hollow part of ship contain air which create buoyant force.
• Ship pushes down in water & displace amount of water which is equal to weight of ship

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Amount of water displace by ship = total weight of ship.

Colour of Indian navy ships

• Ship is painted darker gray universally. Because gray colour has low frequency which prevent easy visualization. Difficult to be spotted in large sea area.
• Lower surface of ship painted red. Red colour is lead pain with copper oxide coating use tom prevent drag and act as biocide too. Prevent rust in salt water
• Submarine upper surface painted black because black absorb most of colour and reflect least amount of light

Types of models

Static model (VIP Model)

• A non-moving, decorative model made for display purposes only.
• Often highly detailed and built to scale, using wood, plastic, or metal.
• Used in museums or as collector’s items.

Sailing model

• A model ship designed to actually sail on water, usually powered by wind (sails).
• Can be used in ponds or lakes. Hulls are often sealed to make them float and remain waterproof.

Working model

• A functional model that demonstrates real-life ship mechanisms, like engine movement, pulley systems, or rudder control.
• Used in educational or demonstration contexts to explain how ships work.

RC model

• These are remote-controlled ship models powered by electric or fuel engines.
• They can move in water and are controlled using a transmitter.

Things used in RC model

Transmitter

• Operates the model in ahead and astern direction & rotational direction of 360
• Run with 12v DC (8 batteries of 1.5v)

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Receiver

• Fitted in model to receive the orders from transmitter and works as ordered
• Runs with 6v DC (4 cells of 1.5v)

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Servers

• Operates with the help of receiver as per order passed by the transmitter and it will run as per the orders of receiver

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Ship Modelling Competitions

SM Competitions are held between Dtes. as part of RD Banner Competitions. This lecture is aimed at apprising cadets on various types of competitions held and criteria for judging models.

SM competitions are held during following camps

• RDC
• NSC
• ATC SW

Types of models in competitions

Camp Model

• Camp Models are made during a particular camp within a specified period as per admin instructions/ ADJI of respective Camps. The type of model is usually power model

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Dte. Model

• These models are made during preparatory camps prior to actual camp where competitions are held. The types of model are usually sailing, RC and Open Class.

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VIP Model

• Solid Model made prior to the camp which may carry specific marks towards RD Banner Competition.

Criteria for evaluation

Static

• Proximity to the drawing
• Model Dimension to the scale
• Fittings.
• Elegance.

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Stability

• Draught and Trim
• List
• Righting Moment.

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Sailing Model.

• All models are made to do a run from one side of the tank to the other powered by sails alone.
• The model taking minimal time is judged first and timing is taken from that model.

Performance.

• Power model are assessed for operational performance through a straight run and or turning circle

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• Straight Run
• The Model is made to run to a Centre Mark at the middle of the tank from the opposite side.
• Graduations of 6” are made on either side of the center mark representing loss of one mark each.

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• Turning Circle
• It is made to do a turn. The model with the smallest turning circle gets the maximum marks.

Stabilizing a ship model

One of the big advantages in ship modelling is that almost anything will float, and with sufficient power it can be propelled through the water. This provides satisfaction to the casual model maker.

• A model’s first contact with the water usually comes some time before the last coat of paint is dry and the last details refitted, however, it is far more practical to test the model during construction, since alteration of subsequent position of components becomes a major operation.
• The time for this is normally after the initial two or three coats of paints and, if possible, before permanent attachment of the deck and superstructure.
• Mark the water line at stem and stern with pencil marks, and place components, or equivalent weights in correct position and check that the hull floats true.
• If after completion, ballast is required to bring the model down to her marks or to correct trim, determine the required amount and its position by stacking cut chunks, flakes and shots of lead in place, then melt the lead in to a convenient block and place or screw, to the hull bottom as low as possible
• But for other types of hull like planked hull or hard chine hulls, where the bulkheads are used for making watertight compartments and are glued with the keen, this process should be carried out in the manner explained.
• After stacking the flakes or shots in the correct position between the bulkheads, melt the lead and make the blocks according to the space available and then place/ glue them as near as possible to the keel.

Terms related to stability