The fight for the survivability of the ship should include training, landing, survival, signals and communications. Five aspects allow you to create a complete rescue system. Marine rescue equipment is an important measure to protect the life and safety of personnel on board. The operation of life-saving equipment must comply with the relevant conventions, norms and requirements of the agreement.
Ship hull structure - protection systems
The structure of the ship's hull is the most important factor in shipbuilding. It is also a key area where any tool requires more adaptation, as the structure presents unique challenges for the shipbuilding industry. Now there are special solutions that allow designers to capture the entire design field and reuse knowledge and design. This significantly reduces the time required to design similar vessels.
Since not all structural parts of the hull are standard, programs provide effective interactive tools for creating individual parts. Copy and paste allows you to reuse existing design components to quickly complete drillthrough. These stages may include variables such as:
- profiles before body bends;
- before rolling the ship;
- degree of heating of individual components.
For other works, for example, cutting, a separate range of possibilities is provided so that the work is carried out according to the prototype of the designed object.
- On the center line of the lower structure is the keel, which is often said to form the base of the ship. This greatly contributes to the longitudinal strength and effectively distributes the local load arising from the docking of the vessel.
- The most common form of keel is what is called the “flat plate” keel, and it is installed in most ocean and other ships.
- The keel shape used on smaller vessels is a keel bar. It can be installed in trawlers, tugboats, as well as on small ferries.
- Where grounding is possible, this type of mechanism is suitable for massive sweeps, but there is always the problem of increasing traction without additional load capacity.
Channel keels are provided in the double bottom of the vessels. They originate in the front partition of the engine room and are aimed at protection against collisions, they are used for laying a double lower pipeline.
The housing requires laying a plate in the bottom for every 3.05 m and frames for every meter. For each layer of the bottom 3 frames are used. They are attached to the transverse corner of the iron joint. For aft rig of a peak tank or collision bulkhead frame, the maximum framing step is 0.61 m. In addition, for a ship’s sight, the maximum frame interval is 700 mm (this helps prevent damage due to a collision). There is also a metal frame under the engine. The keel plate is made of a heavier section of the plate and has conical ends so that it can be welded to the normal coating of the body. The space is not wasted, but used to transport oil fuel and fresh water, which are necessary for the vessel, as well as to provide ballast power. All structural elements of the vessel are designed according to earlier developments.
The minimum double bottom depth on a ship will depend on the requirement of the classification indicator for the depth of the central beam. Ballast cylinders are usually delivered straight forward and backward for trimming purposes, and if necessary, the depth of the double bottom can be increased in these parts. In addition to the rest of the rooms, the double bottom depth is also increased to allow the use of lubricating oil and fuel oil. An increase in the height of the inner bottom always occurs with a gradual narrowing in the longitudinal direction, without sharp breaks in the structure.
Ship design - how not to sink in case of failure?
The unsinkability of a ship depends on the choice of design and the proper collection of parts. No matter how simple it is in creating the drawings, in reality there always arise difficulties and controversial issues at the testing stage:
- Double bottoms can be framed longitudinally or transversely, but where the length of the vessel exceeds 120 m, it is considered advisable to use longitudinal framing. The explanation for this is that during longer tests on a ship and experiment it is shown that the inner lower shell tends to break if a welded transverse framing is adopted. This bending occurs as a result of the longitudinal bending of the housing, but it can be avoided by galvanizing in the longitudinal direction.
- Vertical transverse tiled floors are provided where the bottom is transversely and longitudinally framed. At the ends of the lower tanks and under the main bulkheads, waterproof or airtight, covering any openings on the floor of the plate, welds are placed around any elements that pass through the floors.
- In other places, "solid tile bottoms" are installed to strengthen the bottom transversely and support the inner bottom.
The bracket floor consists of short transverse substrates mounted on the side of the central beam and the tank. The cladding of the shell forms a waterproof skin of the vessel and at the same time in the construction of the merchant ship promotes longitudinal strength and resists vertical shear forces. The internal strengthening of the sheathing of the shell can be both transverse and longitudinal. It is designed to prevent collapse of the coating under the various loads to which it relates.
Additional reinforcement is provided in the front peak structure, and the lateral lateral equipment is supported by any or a combination of the following elements:
- Stringers positioned vertically at a distance of 2 m from each other, supported by uprights or beams mounted on alternative frames. These elements are stapled to frames.
- Perforated devices located at a distance of no more than 2.5 m from each other. The perforation area is at least 10 percent of the substrate area.
- In the rear part and in the lower hold of deep tank spaces, tension elements are installed in accordance with each stringer or perforated plane in the foreground, which extends 15 percent of the length of the vessel in the front.
The anchor equipment installed on most vessels consists of two agreed units offering a degree of redundancy. These blocks consist of an anchor, a chain, a gypsum or chain hoist wheel, a brake, a hoisting motor and various chain stops. When not in use, the chain is stacked in a cabinet; systems with wire are stacked on a drum just like winches. In a chain locker, consisting of a perforated plate, a false bottom is installed. This allows you to remove water and dirt from space, acting as a life-saving tool on a ship. The end of the chain is attached to the case by a quick release mechanism.
Fire - The Most Common Causes
The risk of fire on board the ship cannot be eliminated, but its consequences will be significantly reduced if the recommendations are faithfully followed. Fire safety rules on ships is the first thing that the crew and people at risk are taught. Brief instructions can also be given to passengers before evacuation, if there is a real threat to life.
- Typically, a fire can be easily extinguished in the first few minutes. Prompt and correct action is needed.
- The alarm should be raised immediately. If the ship is in port, call your local fire department. If possible, an attempt should be made to extinguish or limit the fire by any suitable means - portable fire extinguishers or oil filters.
- Ship personnel should be aware of the use of different types of fire extinguisher and their suitability for different types of flame.
- Water extinguishers should not be used in oil or electric fires, and foam ones should not be used in electric flashes of fire.
- The openings in the space must be closed to reduce the flow of air into the room with the flame.
- Any fuel lines that fire or are at risk isolate.
If practicable, flammable materials adjacent to the fire should be removed. It is also necessary to take into account the boundary cooling of neighboring compartments and control the temperature if spaces are otherwise inaccessible. Once the fire has been extinguished, precautions should be taken against its spontaneous ignition. Sailors must not re-enter the space in which the fire occurred without the use of breathing apparatus until ventilation is carried out. Such methods of extinguishing fires on ships are used wherever there is a threat to human life and health.
What is the main problem of sinking ships?
Fires are not so terrible for ships as the opportunity to run aground. This collision with land is dangerous, but you can get out if you do not talk about glaciers. On the other hand, the most terrible is the likelihood of a ship sinking. How does the calculation of “agility and maneuverability” take place, and why are architects not always sure of the reliability of ships? The struggle for the survivability of the vessel is coupled with physics and mechanics, but do not forget about safety measures, because on the example of the Titanic, which was declared the most unsinkable ship, several errors can be identified.
At an altitude of almost 275 meters with a total weight of about 42,000 metric tons, the Titanic was the largest ship ever built at that time. In its lower part there were 16 large waterproof compartments that could be closed in case of a punctured case. However, the luxury liner sank less than three hours after a collision with a massive iceberg in the North Atlantic, despite some estimates that it was supposed to stay afloat for three days after the accident.
Watertight compartments turned out to be a fatal design flaw, which James Cameron illustrated well at the beginning of his 1997 film, talking about the fateful April night in 1912. Then the Titanic went to the bottom, taking more than half of the 2,200 passengers into ice shackles. The 90-meter "wound" in the Titanic hull made the ship fill with water, flooding six compartments.
When enough water got into the gap of the hull, the ship turned at an angle, because of which part of the water passed into the compartments of the front of the ship. But according to the architectural schedule and drawing, they should have remained “dry”. If the partitions were higher, water rushing into the hull could be distributed more evenly, giving passengers more time to escape. Who would have thought that the ship would bend over, because the calculation at that moment was not done. Before “launching into the water”, the ship passed the test, where the compartments filled with water were blown up. The ship stayed for 2.5 months on the water, and then returned to the port. This failed the creator.
Equipment on ships - what is it for?
As mentioned above, the fight against water entering the compartments of the hull is not a problem if you know how to eliminate it. Drying devices are used that “fix” the flow of water into the housing, which saves time for its elimination. Otherwise, adhesives are used that need to be wound up and drained. Further, a struggle is under way for the accident-free compartments of the ship. Soft and hard plasters are used on the fishing vessel.
The first ones include:
- chain mail;
- lightweight;
- shpigovanny;
- training plasters.
The latter take the form of cases, which facilitates the work with water plugs. Semi-rigid plasters that are able to take the form of a cylindrical surface:
- mattress patch;
- curtain and flexible plasters - they are equipped with soft sides.
Hard ones include:
- wooden plasters with soft sides;
- patches with metal valves;
- patches with a clamping bolt.
The rules established the process of using only two types of mechanisms to save the ship. If they fail, accordingly, nothing else will help save the ship. Then the organization of the crew’s struggle for the survivability of the vessel follows, and only then people are saved.
Emergency equipment: rescue of drowning - crew’s business
When it makes sense to escape, urgent safety measures and evacuation of people are applied. Rescue operations are carried out directly by the crew. Diving operations are being carried out to seal the intake openings, and water is also pumped out of the ship’s hull by means of mobile drainage devices. On board must be available and in good condition all the inventory means to carry out the struggle for the survivability of the vessel.
Communication with land - signals and notifications
When it makes sense to involve additional rescue measures, it is recommended to turn to various mechanisms of warning signals. On each ship there are devices for sending SOS signals. This is a universal method of attracting attention among sailors and not only. Fire in the form of fireworks or flames is fired from the ship, so that air transport and neighboring ships can see it.
Radio communication on board - how does it work?
Radio equipment among ships is also used. If it does not work, then the SOS signal is triggered. This is an extreme measure. In other cases, by radio, the captain of the ship contacts the towers and lighthouses to transmit a signal for help. Used and lights, flashes, bright lights. SOS-notification should be of the correct form - straight lines and sharp corners, which are not found in nature, which means that it will be noticeable faster.
Collision Rescue
When a ship collides with ice blocks, the same rescue operations are used. They are advisable when it is possible to dive under water. If the ship is sailing in cold waters, then there are protective suits on the deck. Ultimately, the crew and passengers are evacuated by means of boats and boats. The struggle for the survivability of the ship ceases, a distress signal is transmitted.
Evacuation from ships - what should be done first?
Since it is quite difficult to lower people from the ship, first of all, you need to make sure that there are all measures for the implementation of rescue operations. First, “holes” are locked in the housing, which saves time for the release of people. At the same time, the emergency supply of the vessel is carefully checked, which can help save an extra few hours before the arrival of the rescue team. Apply:
- pillows with tow;
- shpigovanny mat;
- sliding emphasis;
- clamps and special bolts;
- boards and boards;
- wedges and corks;
- cement;
- water glass, sand, minium;
- canvas, felt, tow, nails, staples, wire, rubber sheets.
Only after using all the equipment for its intended purpose can we talk about saving people. Otherwise, time will be wasted, and the ship will sink to the bottom faster than expected in terms of architectural design.