A ship is like a floating city having several different parts. However, we can’t imagine a ship without its three main parts: The Hull, an engine room and a navigation bridge.
A ship comprises both visible as well as invisible parts. E.g. rudder, anchor, bow, keel, accommodation, propeller, mast, bridge, hatch coves and bow thrusters are some common visible parts. In contrast, bulkheads, frames, cargo holds, hopper tank, double bottom, girders, cofferdams, side shell etc., are the invisible parts of a ship.
To understand parts of a ship, one must have to go through some common terms.
The most forward part of a ship is called a Bow; the left-hand side of the ship is referred to as port, whereas the right side is called starboard. Likewise, the front side is termed as forward and the backside as astern.
Now let us discuss some main parts which are common to all types of ships.
Monkey Island:
Monkey Island is a sort of deck located at the topmost accessible height of the ship and just above the bridge.
This part of a ship is sometimes also referred to as a flying bridge and, in the past, was used by the sailors for solar and stellar observations. In addition, it houses a magnetic compass.
It is an integral part of ship and houses driving units such as VDR capsule, AIS Tx/Rx antennae, Radar scanner(s) attached to the radar mast, Sat C/F77 Tx/Rx antennae, communication equipment gear, various halyards connected to the yardarm to hoist flags, weather vane, and the masts leading up to the ‘Christmas Tree’ (navigation lights) and the ship’s aft whistle.
The ship’s bridge is the commanding station of a ship. It controls the ship movement through its navigational equipment.
It controls important deck machinery, main engine and ship’s navigation system.
Functions that are usually performed on the ship bridge are: controls the ship’s speed and direction (navigation), monitor weather and sea conditions, navigating and fixing the position of the ship, and facilitating internal as well as external communication.
Funnel:
A Funnel or Stacks is a chimney on a vessel used to discharge engine and boiler smoke.
Lifting of the exhaust gasses, clear from the deck, is the constitutional purpose of the Funnel.
Accommodation:
The accommodation area is the house for crews and lives. It has all the amenities, including offices, gym, crew cabins, hospital, salon, recreation room, common rooms, laundry, and galley.
It is a key part of the ship and consists of the garbage disposal system, freshwater system, sewage treatment plant, refrigeration system (domestic) and air conditioning for the accommodation block.
It is a necessary part of a ship and facilitates space for relaxing, medical facility and food courts.
The funnel releases exhaust gases into the atmosphere from the engine exhaust room of the ship. It has a similar function to chimneys in factories.
Nowadays, extra care has been taken in discharging shoot from the funnel to preserve the atmosphere from pollution.
These funnels are never installed straight but inclined at a certain angle toward the aft so that the flue gases will not cause hindrance to the deck and navigation bridge.
Boat Deck:
The deck floor covers the ship hull structure. There can be multiple decks or deck sections on a ship. The deck at the top, which bears maximum exposure to weather, is the main deck or weather deck.
Based on the position of a ship’s deck, decks are of six main types; main deck, poop deck, upper deck, lowers deck, weather deck and foredeck.
The boat deck’s main function is holding the hull structure and providing the floor to work and standing and guard them against outside weather.
Mast:
The mast is a rangy spar arrangement that is elevated more or less vertically to the Centreline of a ship.
It has several purposes, including carrying derricks and giving fundamental height to the navigation light, salient yards, radio or radar aerials, and scanners.
Flying Bridge:
It is an extended area on top of a weather deck or an open area of the superstructure, which provides an unobstructed view of the fwd and aft along with the vessel’s sides to the navigational officers.
It also serves as an operating station for the officer and crew of the watch.
It also contains a duplicate set of controls, which is vital for the master, ship’s officers, and pilot for berthing and unberthing the vessel.
Stem:
The front-most part of the boat or ship’s bow is termed as the Stem of the ship.
The keel itself is extended up to gunwale to form the curved edge called the ship’s stem.
These stems can be of two styles viz. raked and plumb stems, where the former is inclined at some angle to the waterline and later is perpendicular to the waterline.
Forecastle:
The forecastle is one of the foremost parts of the ship of length less than 7% of the total deck length.
It was initially used in military vessels, in which the soldiers used forecastles to take defensive positions.
But, today, forecastle serves many functions such as holding, anchoring and securing the major parts of the ship.
Foredeck:
The foredeck is the forward part of a weather deck, between the superstructure and the foc’sle superstructure.
Basically, it is a part of the vessel forward of the mast.
Bulbous Bow:
It is a jut out bulb at the bow of the vessel just below the W/L.
It cuts the water and tweaks the water flow around the hull, increasing the vessel’s speed, fuel efficiency and stability.
12-15% of better fuel efficiency is observed in the vessel with the bulbous bow.
It also increases the buoyancy of the onward part of the vessel, which reduces pitching up to some extent.
It serves as a roof to the cabin constructed in the aft of the ship.
It facilitates the captain and helmsman to supervise the entire working crew.
But in modern ships, the poop decks are provided either in the centre of the ship or on the starboard.
Side Thrusters:
These are somewhat like a propeller and fitted on either side of the bow of the ship.
It helps in manoeuvring ships at a slow speed in congested waters near ports or canals. These are also referred to as tunnel thrusters.
Side thrusters influence the total running cost of a ship to a greater extent. These are either hydraulically or electrically powered.
Rudder:
Without steering, we can’t move a vehicle in the desired direction, so the propeller propels the ship, and the rudder steers the ship. The rudder is a flat hollow structure housed in the aft of the propeller.
It consists of the following parts: rudder trunk, moveable flap, main rudder blade, hinge system, links and rudder carrier bearing. Rudders are of three types: balanced type, semi-balanced type and unbalanced type rudder.
As a vital part of the ship, the rudder is provided with a steering gear system that controls the rudder’s movement. It works on Newton’s Third Law of motion.
It is a mechanical device having blades fitted on a central shaft. These blades rotate, and their rotational energy is converted into pressure energy, and due to this, the propeller produces the thrust required for propulsion. It pushes the seawater backwards, and, in turn, the seawater helps the ship move forward.
Engine, shaft and propeller together constitute propulsion unit. The propeller should be made up of aluminium, bronze, manganese etc., which are excellent corrosion resistant alloys. There can be one, two or three propellers.
It is the most important part of the ship without which a ship can’t move. So, the main function of the propeller is to propel the ship in the forward direction by producing thrust on water. Its working principles are Newton’s third law of motion and Bernoulli’s theorem.
Paint Room:
A small onboard area is required in marine vessels to handle and store paint. This room is known as the Paint room.
Special provisions are there for the paint room to cater explosions and release of chemical gases and vapours from these enamels.
There should be explosion-proof lighting in the paint room, and brackets should be available to provide flexible mounting and storage of paints.
Emergency Generator Room:
When the main supply goes out of order, a small separate generator supplies electricity for emergency loads. This is called an emergency generator.
It is located above the topmost deck, away from main and secondary machinery and collision bulkhead, and has its own switchboard in its surroundings.
This generator should be easily operable and can be started at even 0°C
Ballast Tanks:
The compartments maintained specially to carry water, which serves the purpose of ballasting and stabilizing the vessel, are termed Ballast Tanks.
These tanks should be provided with proper care to prevent corrosion, as seawater is highly corrosive.
These tanks are revolutionary to the marine industry as, before their evolution, solid ballast was used, and their discharge is quite difficult compared to easier pumping of liquid ballast.
A duct keel is a hollow structure that consists of two longitudinal girder and solid plates and is welded to form a box-type structure, which is generally provided in double-hull ships.
The duct keel should provide a watertight passage along the ship length. It consists of a sounding pipe for leakage detection.
This is a multi-functioning part of the ship for performing several functions like provide resistance to loads, carry water pipelines, ballast pipelines, oil pipes, etc.
Derricks (Cranes) are used to lift and carry the safe working load on a ship.
These are electrically or hydraulically operated equipment for easier operations.
The capacity of ship cargo cranes and gears for handling cargos is 15 tons to 4000 tons per hour.
Samson Post/King Post:
It is a heavy vertical post that supports the cargo booms.
It rests on the Keelson and supports the deck beam of a vessel.
Cargo hold:
Enclosed spaces to retain and store cargo or freight containers carrying coal, grain and salt are referred to as cargo holds.
The cargo hold is located under the ship’s deck and has a holding capacity ranging from 20 tons to 200000 tons.
The main function of the cargo hold is to preserve cargo when it is transported to the destination.
Hatch Cover:
To prevent the cargo storage from spoilage, especially to make storage spaces airtight and watertight, hatch covers are required. Generally, to save the food items ( or any other cargo) transported by ship from rain during the voyage.
The design of the hatch cover changes according to the type of the vessel, but the only requirement is that it should be quick enough to provide faster cargo handling processes.
In the past, these hatch covers were crane or winch driven, but today, mainly hydraulically driven hatch covers are used.
Freeboard can be defined as the distance measured from the waterline to the higher edge of the freeboard plating/deck plating at the sides of amidships.
The classification society must approve the minimum freeboard calculation for a vessel.
The calculation of freeboard plays a critical role in defining the load line marks of the vessel, which in turn, is directly related to the cargo-carrying or the earning capacity of the vessel.
Hull:
The hull is a watertight vessel’s body that may be open or partially covered with a deck.
Hull has several watertight decks and bulkheads as the major transverse membrane.
The intermediate member of the hull consists of girders, webs and stringers.
Depending on the structural arrangements, there may be longitudinal members for strengthening purposes.
The ship, an important trading source through seaways, may be made up of different styles and sizes. Some parts are called essential parts, common to all ships, but others are just accessories to provide luxurious or improved shipping.
All the parts which form the ship should be checked for proper working, and precautions should be taken for risky equipment.
Three necessary parts of the ship are the hull (the main body of the vessel), navigation bridge (helps in directing the ship in the proper direction) and engine room (propels ship or helps in moving). However, today modern ships are equipped with the most modern equipment and technologies to their different parts to improve voyages at sea.
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