Barotrauma of the paranasal sinuses. Ship structure
Have you noticed how easy it is for us to breathe at sea? The thing is that sea air contains small particles of sea water rich in minerals. By acting on the mucous membrane of the respiratory tract, they not only moisturize it, but also help epithelial cells work more efficiently.
Rinsing the nose with sea water has been practiced for a long time, but it was not immediately possible to scientifically prove its positive effect on health. There is still an opinion that a solution of table salt (or saline solution) is comparable in effectiveness to seawater-based sprays.
However, this does not correspond to reality:
Exposure to minerals is only possible when using sea salt. In addition to sodium and chlorine, sea water contains magnesium and calcium ions, which stimulate the functioning of the nasal mucosa. Magnesium ions are especially important, which contribute to the production of energy necessary for the ciliated cells of the mucosa to remove pathological microorganisms from the nasal cavity 1;
Mechanical cleansing will help both in the prevention and treatment of a runny nose. The effectiveness of the prevention and treatment of runny nose through regular nasal rinsing has been repeatedly subjected to clinical studies both in Russia and abroad.
Nasal rinsing helps with diseases such as colds (ARVI), rhinitis (runny nose), sinusitis (inflammation of the sinuses), allergic rhinitis, and also with respiratory diseases associated with air pollution in big cities and at work 1. Rinsing the nose with sea water, as part of complex therapy, will help avoid the development of such unpleasant complications as, for example, otitis, sinusitis, frontal sinusitis, as well as chronicity of the process 1;
Thinning mucus and making it easier to remove from the nose also occurs in different ways. Regular rinsing of the nose with sea water prevents the thickening of mucus in the nasal cavity and cleanses the mucous membrane of bacteria, viruses and allergens, improves the performance of microcilia, which are responsible for the distribution of mucus in the nasal cavity and the removal of mucus, and with it bacteria, viruses, and allergens from the nasopharynx.
To learn how to rinse your nose correctly, watch our animated video on this topic.
Remember personal hygiene and nasal hygiene. Marimer sea water can help with the latter.
Marimer is natural sea water for the prevention and treatment of runny nose. Thanks to the innovative spray system, in one injection many microdroplets of sea water are gently distributed throughout the entire nasal cavity and help to effectively clear it of mucus 2.
Each microparticle of Marimer sea water contains useful microelements that help support the protective functions of the nose from the very beginning of treatment of a runny nose. The unique structure of the can helps to avoid unpleasant sensations, ensuring soft and comfortable use. A wide range of products will allow you to choose the appropriate format for each family member 2.
Marimer sea water is collected every day, far from the coast at a depth of several meters in the waters of the Atlantic in a bay near Saint-Malo. This bay has powerful ebbs and flows, and the constant mixing of the water provides a rich variety of seaweed, which means a high content of mineral elements.
Sterility is ensured through a microfiltration process without irradiation and the use of antiseptics (no chemicals are used when treating water). Within a few days after collection, the water is bottled. During the production process, water quality is monitored to ensure the highest level of safety. A special valve in the nozzle prevents bacteria and other contaminants from entering the bottle.
An innovative spray system (micro-diffuse) creates the optimal size of aerosol droplets/particles, ensuring accurate and continuous spraying, uniform and maximum distribution of the solution on the surface of the mucous membrane.
1 G. S. Maltseva, “The use of sea water for the prevention and treatment of diseases of the nasal cavity and nasopharynx in children.” // Journal "Pediatrics", No. 03, 2013.
2 Instructions for the medical use of the drugs MARIMER FORTE and MARIMER dated 05/07/2015 and 05/06/2015.
Modern ships are made from materials whose density is many times higher than the density of water. But they do not sink because they are designed in such a way that they have many rooms filled with air inside.
When talking about a ship, we use the terms " ship " or " vessel ". Meanwhile, these concepts do not mean the same thing. In general, a ship is considered to be any vehicle, which is used to transport passengers and cargo by water. Different rules and codes interpret this concept differently. For example, the International Regulations for Preventing Collisions at Sea states that a ship is any means of transportation on water. Therefore, a ship is a broader concept. And ships are generally considered to be large sea vessels and vessels of any size that fly a naval flag. Each ship has its own unique name, flies under the flag of the state in which it is officially registered.
How the ship works
1 – bow, 2 – bulb, 3 – anchor, 4 – side, 5 – stern, 6 – stern, 7 – chimney, 8 – wheelhouse, 9 – deck.
The ship's hull consists of several parts.
The front part is called nose . As it moves, it cuts the waves and is therefore shaped in such a way that water resistance is minimal. The anterior tip of the nose is called stem . And the part of the nose protruding below the waterline is called bulb . It changes the direction of water flow through the hull, thereby reducing drag, increasing the speed of the ship and reducing fuel consumption.
The back of the ship is called stern It is divided into surface And underwater parts. In the underwater part there are steering wheel And propeller screw . On the surface there is an engine room and a cargo compartment.
The side part is called board . Bulwark - This is the part of the side located above the deck.
The interior space of the ship is divided vertically into rooms by a horizontal ceiling - deck. There can be several decks: upper deck, wheelhouse deck, superstructure deck, forecastle deck, first, second deck, etc. It all depends on the size and purpose of the ship. For example, lifeboats are located on the boat deck. Passenger ships have special promenade decks.
Along the bottom of the vessel, from bow to stern, there is a longitudinal beam called keel . It ensures the strength of the hull and bottom.
The line of contact of the hull with the calm surface of the water is called waterline . It conditionally separates the surface and underwater parts of the ship.
In order to stay in one place, the vessel must be thrown onto the ground when parked. anchor .
Marine engine sets in motion ship propulsors : air and propeller, paddle wheel). On sailing ships, the propellers are the sails. (Propulsors are devices that convert engine energy or any other energy, such as wind energy, into work to move a vehicle.)
The vessel's water resistance, buoyancy and unsinkability are ensured by frame . It consists of a casing and a set.
Center of mass and center of pressure of the ship
When a ship floats, it is acted upon by two forces, equal in magnitude and opposite in direction: gravity (weight) R and buoyant force.
Ship weight R - this is the sum of the weights of the hull, mechanisms, fuel, water reserves, crew, weapons, etc. The force of gravity is always directed downward and pulls the ship to the bottom. It is applied to a point called the ship's center of gravity, or mass center of gravity . When designing and building a ship, they try to ensure that its center of gravity is at center plane . This is a vertical plane that runs through the entire length of the vessel and divides it into 2 symmetrical parts. The center of gravity is located either at half the height of the freeboard or slightly below it.
The buoyant force is applied to the geometric center of gravity of the immersed volume of the ship and is directed vertically upward. The point of application of the buoyant force is called pressure point , or center of pressure .
When a ship is created, they make sure that both of these centers (the ship’s center of gravity and the center of pressure) are in the center plane on the same vertical.
Equilibrium equation for a ship has the form:
P = γ (V o −V n) , or:
P = γ V
Where
V n - waterproof volume of the ship above the waterline,
V o – the entire waterproof volume,
P - weight of the vessel,
γ - density of water,
V - immersed volume
This equation is called basic buoyancy equation.
Buoyancy reserve
Buoyancy is the most important seaworthiness of a ship. This is the ability to stay afloat along with the loads necessary to perform certain tasks. Having lost buoyancy, the ship will sink.
Each ship has buoyancy reserve , which is defined as the percentage of all watertight volumes of a ship located above the waterline to its total watertight volume.
W = V n / V o * 100
From a physics point of view The buoyancy reserve is equal to the volume of water that the ship can take on board while remaining afloat.
For example, if the reserve of buoyancy is 50%, then the ship is immersed in water such that its watertight volume above the waterline is equal to the volume below it.
The volume of superstructures and all protruding parts on the upper watertight deck is not included in the buoyancy reserve. The volumes of damaged compartments are also excluded from it.
If a ship takes on board an amount of water equal to its buoyancy reserve, it will sink into the water up to the main deck. Its reserve of buoyancy in this case will become equal to zero. And the ship itself will be in an unstable position. In physics this is called neutral buoyancy. Even a small impact on a ship in this state can cause the buoyancy to become negative and the ship to sink. Therefore h In order for navigation to be safe, it is established for any ship mandatory reserve buoyancy . It is designated cargo waterline or load line – a special mark applied to the vessel. It shows the level to which the ship can be loaded. The larger the load, the closer the load line is to the water.
To preserve the buoyancy reserve, the ship's hull and all its premises are made waterproof. They are separated by bulkheads and decks. Doors, portholes, and hatches are waterproof. If water enters any room on the ship, it will not be able to penetrate into other rooms. It is very important that all these ship structures are always in good condition.
Traveling along rivers and seas on ships has been known in history for more than five thousand years. Today, according to generally accepted terminology, a sea vessel is a cargo, passenger or commercial large-sized watercraft, and a ship is a military one. The list of ships could take a long time. The most famous marine ones are sailboats and yachts, passenger liners and steamships, boats, tankers and bulk carriers. Ships are aircraft carriers, battleships, cruisers, destroyers and submarines.
Ship structure
Whatever type or class the watercraft belongs to, it has common design elements. First of all, of course, the hull, on which superstructures for various purposes, masts and deckhouses are installed. An important element of all ships are engines and propulsors, in general, power plants. Devices, systems, electrical equipment, pipelines and premises equipment are important for the life of a watercraft.
They are also equipped with spar and rigging.
The bow is the front end, the stern is the rear end of the hull, and its side surfaces are the sides. Sailors call the starboard side in the direction of travel the starboard, the left side the backboard.
The bottom or bottom is the lower part of the ship, decks are the horizontal floors. The hold of a ship is the lowest room, which is located between the bottom and the lower deck. The space between decks is called a tween deck.
Ship hull design
If we talk about a ship in general, be it a warship or a civilian vessel, then its hull is a waterproof, streamlined body, hollow inside. The hull provides the ship's buoyancy and is the base or platform on which equipment or weapons are mounted, depending on the purpose of the ship.
The type of vessel determines both the shape of the hull and its dimensions.
The ship's hull consists of a frame and plating. Bulkheads and decks are elements inherent to certain types of ships.
The sheathing can be made of wood, as in ancient times and today, plastics, welded or riveted steel sheets, or even reinforced concrete.
On the inside, to maintain the strength and shape of the hull, the hull and deck are reinforced by a set of beams, wooden or steel, rigidly fastened together, which are located in the transverse and longitudinal directions.
At the ends of the hull most often ends with strong beams: at the stern - with a sternpost, and at the bow - with a stem. Depending on the type of vessel, the contours of the bow may be different. Reducing resistance to the movement of the vessel, ensuring maneuverability and seaworthiness depend on them.
Underwater nose the ship reduces water resistance, which means the ship’s speed increases and fuel consumption decreases. And on icebreakers, the stem is strongly inclined forward, due to which the ship crawls onto the ice and destroys it with its mass.
Case set
The hull of any vessel must have strong connections in the vertical, longitudinal and transverse directions to withstand water pressure, wave impacts during any storm and other forces that act on it.
The underwater parts of the ship experience the main load. Therefore, in the middle of the bottom frame, the main longitudinal connection is installed, which absorbs the forces arising from the longitudinal bending of the vessel - the vertical keel. It runs the length of the hull, connecting to the stem and sternpost, and its design depends on the type of vessel.
Bottom stringers run parallel to the keel along it; their number depends on the size of the ship and decreases towards the bow and stern, as the width of the bottom becomes smaller.
Often, to reduce the influence of the ship's sideways motion, side keels are installed; they do not exceed the width of the hull and have a different design.
Vertical steel plates, called bottom floors, are installed across the hull and welded to the keel and can be permeable or impermeable.
The side frame continues the bottom frame and consists of stringers (longitudinal beams) and frames (transverse stiffeners). The stem is considered the zero frame in naval shipbuilding, and the middle frame is the midship frame.
The deck set is a system of intersecting longitudinal and transverse beams - beams.
Ship shell
The shell of the vessel consists of outer bottom and side plating and deck plating. The outer cladding is made of horizontal separate belts connected in various ways: overlapping, end-to-end, smooth, herringbone.
The underwater parts of the ship must be the strongest, so the lower (tongue) plating belt is made thicker than the intermediate belts. The thickness of the plating belt, called shearstrak, on the beams of the upper continuous deck is also the same in thickness.
The deck flooring consists of the longest sheets that rest on the same deck structure and limits the top of the ship. The sheets are placed with the long side along the vessel. The smallest thickness of metal decking is 4 mm. can also be made from boards.
A deck is a combination of decking and decking.
Ship deck
The height of the ship's hull is divided into several decks and platforms. A platform is a deck that does not run the entire length of the ship, but only between several bulkheads.
Decks are named according to their location on the ship: lower, middle and upper. At the ends of the ship (bow and stern), platforms run below the lower deck and are counted from top to bottom.
The number of both decks and platforms depends on the size of the vessel, its purpose and design.
River vessels and mixed navigation vessels have one main or upper deck. Marine, such as passenger ship, more precisely, a passenger ship, three decks.
Large lake passenger ships have an intermediate deck, in addition to the main one, forming an interdeck space.
A cruise ship can have significantly more decks. For example, on the Titanic there were four of them, stretching along the entire length of the ship, two platforms that did not reach either the bow or the stern, one was interrupted at the bow, and one was located only in the front of the liner. The newest Royal Princess liner has nineteen decks .
The upper deck, also called the main or main deck, withstands the greatest stresses during transverse compression and longitudinal bending of the hull. The deck of a ship is usually made with a slight rise in the center towards the bow and stern and a convexity in the transverse direction, so that water that falls on the deck during rough seas flows more easily to the sides.
Ship superstructures
Deck superstructures are above-deck structures located across the entire width of the vessel. They form closed volumes that are used as office and residential premises. Side walls are called superstructures, the side walls of which continue the side of the ship. But most often the rooms above the upper deck do not reach the sides. Therefore, there is a somewhat conventional division into the superstructures themselves, which are located over a fairly large length of the vessel, and deckhouses, also superstructures, but short.
Since the upper deck of the ship is divided into sections that have their own names, the same names are given to the superstructures located on them: forecastle or bow, stern or poop and middle. The forecastle - the bow superstructure - is designed to increase the bow of the hull.
The tank can occupy up to 2/3 of the length of the vessel. The elongated forecastle is used for cabins on passenger ships, and cargo tween-decks on cargo ships.
In the aft superstructure - poop or poop - living quarters for the crew are arranged.
Between the superstructures, the deck is fenced with bulwarks, which should protect the deck from flooding with water.
On sea vessels, depending on the type and purpose of the vessel, cuttings are carried out in several tiers.
On river ships, only the rooms containing the helm and radio are called deckhouses, and all other structures on the upper deck are called superstructures.
Ship compartments
The structure of a military or civilian ship implies the presence of watertight compartments, which increase its unsinkability.
The internal vertical walls (bulkheads) are made waterproof, dividing the internal volume of the ship into compartments along the length. They prevent water from filling the entire internal volume in the event of damage in the underwater part of the ship and the spread of fire.
The compartments of the ship, depending on their purpose, have their own names. The main power plants are installed in a compartment called the engine or engine room. The engine room is separated from the boiler room by a waterproof partition. Cargo is transported in cargo compartments (holds). The living quarters for the crew and passengers are called accommodation and passenger holds. Fuel is stored in the fuel compartment.
The rooms in the compartments are protected by light bulkheads. To allow access to the compartments, rectangular hatches are made in the deck flooring. Their sizes depend on the purpose of the compartments.
Marine propulsion system
The power plant on a ship is the engines and auxiliary mechanisms that not only set the ship in motion, but also provide it with electricity.
The ship is driven by a main propulsion unit connected by a shafting.
Auxiliary mechanisms provide the vessel with electricity, desalinated water, and steam.
Based on the principle of operation and type of main engine, as well as energy sources, a ship's power plant can be steam power or steam turbine, diesel, diesel turbine, gas turbine, nuclear or combined.
Ship devices and systems
The structure of a ship is not only the hull and superstructures, it is also ship devices, special equipment and deck mechanisms that ensure the operation of the vessel. Even people far from shipbuilding cannot imagine a ship without a steering or anchor device. Each ship also has towing, mooring, boat, and cargo equipment. All of them are driven and serviced by deck auxiliary mechanisms, which include steering gears, towing, cargo and boat winches, pumps and much more.
Ship systems are many kilometers of pipelines with pumps, instruments and apparatus, with the help of which water is pumped out from holds or wastewater is supplied drinking water or foam in case of fire, heating, air conditioning and ventilation are provided.
The engine room mechanisms are served by a fuel system to power the engines, an air system to supply compressed air, and cool the engines.
Electrical equipment provides lighting on the ship and the operation of mechanisms and devices that are powered by the ship's power plant.
All modern ships equipped with sophisticated navigation equipment to determine the direction of movement (course) and depths, measure speed and detect obstacles in fog or oncoming ships.
External and internal communication on a ship is carried out using radio equipment: radio stations, ultra-short wave radiotelephones, ship telephone exchanges.
Ship premises
Ship premises, no matter how many there are on the ship, are divided into several groups.
These are living quarters for the crew (officers' cabins and sailors' quarters) and for passengers (cabins of various capacities).
A passenger airliner is already a rarity today. Few people allow themselves to move at low speed over long distances. You can travel by air much faster. Therefore, passenger cabins are more of a property of cruise ships.
Passenger cabins, especially on cruise ships, are divided into several classes based on comfort. The simplest cabin resembles a railway carriage compartment with four shelves and virtually no furniture, often facing the inside of the hull and without a porthole or window, with artificial lighting. And the Royal Princess liner also provides passengers with luxurious two-room suites with balconies.
A cabin on a ship, specifically on a military ship, is a rest room for the crew officers. The ship's commander and senior officers have separate single cabins.
Public premises are salons, cinema halls, restaurants, libraries. For example, cruise Oasis liner of the Seas has 20 restaurants on board, a real ice rink, casino and theater, designed for 1380 spectators, night club, jazz club and disco.
Sanitary and utility premises include sanitary and hygienic (laundries, showers, bathrooms, baths) and household premises, which include kitchens, all kinds of storage rooms and utility rooms.
IN office premises Passengers are usually not allowed access. These are the rooms in which the ship is controlled, or where radio equipment, engine rooms, workshops, storerooms for spare parts and other ship supplies are located.
Special purpose premises include cargo holds, solid or liquid fuel storage facilities.
Sailing vessel
Device sailing ship not much different from an ordinary ship. Only sailing equipment, spars and rigging.
Sailing rig - a set of all the sails of a ship. Spar - parts that directly support the sails. These are masts, yards, topmasts, bowsprits, booms and other elements familiar from books about pirates of past centuries.
Special gear, with the help of which masts, bowsprits and topmasts are secured in a certain position, is called standing rigging, for example, shrouds. Such equipment remains stationary and is made of thick resinous, plant-based, or galvanized iron or steel cable, and in some places, chains.
Movable gear, with the help of which the sails are set and removed, and perform other operations related to the control of a sailing vessel, are called running rigging. These are sheets, halyards and other elements made from flexible steel, synthetic or hemp cables.
In all other respects, even in the number of decks, they are similar to their counterparts.
A multi-deck ship under sail appeared in the 16th century. Depending on the displacement, Spanish galleons could have from 2 to 7 decks. The superstructure was also built in several tiers, which contained living quarters for crew officers and passengers.
The structure of a ship, at least its main structural elements, does not depend on the type and purpose of the vessel, be it sailing ships driven by the force of the wind, inflating sails, or paddle steamers with a steam engine as propulsion, cruise ships with a steam turbine unit, or nuclear icebreakers.
Looking at the ship in profile, you can appreciate its outlines and hull lines. The vessel itself consists of a frame, called a frame, and planking. The body kit serves to impart rigidity to the entire structure. It also shapes the appearance of the ship, its contours. You can notice that in the front (bow) part of the ship it has a special shape. The bow of the ship is specially made pointed so that when moving through the water, the ship experiences minimal resistance from the environment.
In nautical terminology, the front end of the ship is called the bow. In its location it is opposite to the stern. The bow of a ship most often has an elongated shape, narrowed from the sides. Its function is to cut waves that prevent the ship from moving quickly. This unique shape of the bow best suits the operating conditions of the ship.
Elements of the bow of the ship
The bow of the ship has a complex structure. It is designed in such a way as to reduce resistance to water elements to a minimum. At the very end of the bow there is a stem. This is a thick beam, which is a kind of continuation of the keel. In the place where the stem approaches the waterline, a metal plate is often placed, which is called a “green” or “cutwater”.
In ancient times on the nose sailing ships Usually they placed decorations in the form of figures - rostras, which performed a decorative function. Such images made it possible not only to make the ship more attractive, but often gave warships an intimidating appearance. Roman warships instead of decorative figures, they often had massive rams in front, with which the nose ended.
The deck elements of the front part of the ship also have their own names. The bow space of the ship's upper deck is called the "tank". On sailing ship the forecastle begins at the foremast and ends at the extreme forward end of the vessel. Sometimes a ship has an elevation on the deck in the front part - a forecastle. This structural element can occupy up to half the entire length of the vessel. Rigging and mooring equipment is installed on the forward part of the deck.
In the area of the bow, the ship's hull has a reinforced structure. The set here is more durable and frequent, and the plating has significant thickness and strength. This is done so that the ship can confidently sail against the wind and strong waves. A strong bow is also needed when touching the pier during mooring. The bow, in any sailing conditions, takes on the main load of the external environment, so the requirements for its design are always more stringent.
When looking at an ocean-going vessel, it is not always possible to imagine how many parts it consists of. What first catches your eye is the external shape of the structure, the contours of the hull and the deck superstructures. Meanwhile, any ship is a complex system that includes a number of elements, each of which has its own purpose and name.
Main parts of the ship
The basis of any ship, be it a small vessel or a giant one ocean liner, is his body. It consists of a set that includes rigid longitudinal and transverse elements, as well as a skin that is attached to the set from the outside. The set in combination with the skin gives the vessel smooth outlines, guarantees water resistance and protection of the hull from damage. This is a kind of backbone, the skeleton of the ship.
Conventionally, the body can be divided into two parts. The front is called the bow, and the back is called the stern. The part of the ship that is below the waterline is called underwater. Everything that rises above the surface of the water is the surface part of the ship. The stern and bow on both sides of the center line are connected by sides.
The horizontal surface at the top of the hull is called the deck. It has long been assembled from boards tightly fitted to each other. One or more vertical masts are installed on the decks of sailing ships, to which sails and rigging equipment are attached.
Large ships are equipped with a superstructure in their upper part. This structure serves as a continuation of the sides and can occupy a significant part of the deck area. A massive superstructure allows efficient use of space on the deck, but impairs the stability of the ship and increases its windage. The control room, which is part of the superstructure, is used to control the ship.
Other ship design elements
In the middle and bow of the ship you can often see a continuation of the side, slightly rising above the surface of the deck. This lightweight structure made of wood or thick canvas is called a bulwark. It can be permanent or temporary. The bulwark is indispensable during heavy seas, when passing dangerous reefs and sailing.
They have their own names and elements of the vessel set. The main longitudinal part of the structure, which runs along the entire hull in its lower part, is called the keel. At the front, the keel becomes a sloping stem. The aft end of the keel is called the sternpost. The steering wheel is usually hung on it. A shaft can also be passed through the sternpost