What Is a Superstructure?

A superstructure is an enclosed building that extends above the upper deck of a ship and extends from one side to the other or its side wall is not more than 4% of the ship's width. Without strict distinction, various enclosed buildings above the upper deck may be collectively referred to as superstructures. ^[1] Sometimes it refers to deck buildings including deckhouses. Above the submarine pressure hull, a structure that is set along the captain and connected to the non-pressure hull is also called a superstructure.

The superstructure is also called "ship building". Or one of the upper continuous decks extending from one side to the other

1. A collective name for various enclosed buildings above the upper deck.

2. A deck structure with a freeboard deck width of at least 92% of the ship's width.

3. Refers to all enclosed buildings on the upper deck. The "Code" refers to enclosed buildings on the upper deck that extend from one side to the other, or whose side panels are not more than 4% of the ship's width inward from the hull panel. ^[3]

The superstructure can be used to arrange various cabins, battlefields, and various devices. For example, the cab is located in the middle of the ship or on the top of the superstructure, which is conducive to expanding the vision of the driver. In the superstructure, there can be passenger cabins and crew living quarters, and some places, such as the deck deck on the first floor, can also be used as cargo holds or store cables, lamps, paint, etc. In addition, the first floor can also reduce deck waves. The superstructure above the cabin can cover the cabin opening and protect it from waves.

The superstructure can also increase the ship's reserve buoyancy, and the port can reduce the waves on the deck. In addition, when the superstructure has a sufficient length, the main hull plus the superstructure will form a hull beam with a certain height and cross-section. According to its location and length, it can participate in the longitudinal bending of the main hull in whole or in part. This can improve the overall longitudinal strength of the hull. At the same time, the serious stress concentration generated by the hull at the end of the superstructure should be paid attention to in the design. ^[3]

The superstructure was originally called the enclosed building above the continuous deck on the upper level. It is divided into two

1. Wave impact: When the ship is sailing in severe sea conditions, the superstructure will be impacted by the waves, especially the first floor. The ship will be the most impacted when the ship is facing the wind and waves. Most impacted.

2. Longitudinal bending: Long superstructures (such as long bridges) in the middle of the ship, and deckhouses in the ship, if the length is large, will bend along with the body of the ship. The first, aft and stern deck rooms are less affected by the longitudinal buckling.

3. Gravity: It can withstand the structural weight of each layer of the building and the local loads of various machinery and equipment, such as the weight of the lifeboat davit on the lifeboat deck.

4. The inertial force caused by ship sway. ^[3]

The superstructure with a length greater than 0.15L and not less than 6 times its height is a long superstructure.

Depending on the type and size of the ship, the number of deck levels and naming methods used in superstructures (bridges) are different. If there is a ship from the first deck below the superstructure, the decks are named according to A, B, C, etc .; some ships are named according to the nature of the use of each deck, such as the compass deck, Bridgedeck, masterdeck, officedeck, boatdeck, crewdeck, etc.

In general, each deck of a superstructure includes the following: (1) compass deck; (2) pilot deck; (3) boat deck; (4) living deck; (5) upper deck in superstructure; (6) Walk deck. ^[3]

The setting of the superstructure and the deckhouse needs to be arranged for various working and living spaces in terms of use functions. From the impact on the technical performance, the superstructure is beneficial to improve the ship's splashability and stability. In addition, it is also important in the art of ship architecture. effect. Therefore, for the choice and arrangement of the form of superstructure and deckhouse, the above-mentioned relationship must be handled well to meet the organic cooperation of reasonable use, advanced technology and architectural art. In the overall design, it is necessary to conduct a comprehensive analysis based on the ship's use, navigation area, engine room status, ship performance characteristics, and facade modeling. In addition, the superstructures and deckhouses at various locations have different roles, so their structural types are also different.

1. First floor

The setting and dimensions of the first floor must first consider the waves on the deck, because when the ship is sailing in the heading or oblique heading, the head is easy to go on the waves. Deck waves will seriously threaten the safety of the crew, cargo, equipment and deck opening closures on the deck. Practice has proved that setting up the first floor is very effective in preventing waves on the deck, keeping the deck dry, and protecting the safety of personnel, cargo and equipment.

The setting of the first building and its length are related to factors such as the size of the ship, the size of the ship's freeboard, the height of the bow, the sea conditions, and the layout of the equipment on the first floor. China's "Classification of Steel Sea-going Ships" stipulates that all ships should have a first floor or increase the bulge so that the minimum height of the bow meets the requirements of the "Code for Load Lines of Sea-going Ships". The code stipulates that for ships with a first floor to meet the minimum freeboard height required by the code, the length of the first floor from the vertical line should not be less than 0.07 Lpp, and the closed conditions of the first floor are also required when the length of the ship is 100 m. Should meet the requirements of the specification. On this basis, the deck area of the first floor should also take into account the layout requirements of anchoring equipment and other equipment. The statistical value of the length of the first building is 8% ~ 10% of the captain.

Generally, the first freeboard of a sea ship is not high enough, so a short first floor is provided. In the short first floor, windlass control rooms, lighting rooms, paint rooms, cables and rigging, woodworking workshops, etc. are arranged.

In addition to the short first floor, some ships start from the actual and use the long first floor. For a cargo ship, in order to make up for the lack of cargo capacity in No. 1 cargo hold, the first floor is extended to the rear end of No. 1 cargo hold and the resulting volume is used for loading. This not only increases the capacity of the cabin and balances the loading and unloading time, but attention should be paid to the adverse impact on stability. Another example is some marine tugboats. In order to improve the immersion during navigation and the tow hook is arranged near the center of gravity of the ship, a long first floor is also provided. However, it should be noted that due to the many opportunities for the first collision, the first floor section of the forefront cabin area is not used as a living compartment.

For small ships, considering the sight line of sight or the height of the center of gravity, there is a half-lift first floor (the bottom of the first floor is below the upper deck). Passenger ships and passenger cargo ships are usually not provided with a first floor because continuous decks are usually provided above the freeboard deck. For large ships with high depth and high sheer, the first freeboard can be guaranteed without the first floor. ^[5]

When modern shipyards construct superstructures, they generally use one level as a subdivision, and also use the center plane as the boundary. After the segment manufacturing is completed, it will be sent directly to the general assembly site for final assembly of the superstructure. The maximum quality can reach 500 ~ 750t. Its segmented pipeline is generally set with 6 stations:

1. Positioning Place the board on the assembly line for positioning;

2. Welding with single-sided welding for plate welding;

3. Scribing and cutting CNC scribing and cutting;

4. Installation of spot welding positioning for reinforcing ribs;

5. Automatic or semi-automatic welding for rib welding:

Then enter the segmented assembly area and set up three separate stations for segmented assembly, outfitting installation, and welding. Segmented assembly is performed on a special bracket. When completed, the bracket can be used to lift the transport device to the end of the area, and then to the final assembly site for general assembly.

At present, domestic shipyards do not yet have a superstructure segmentation pipeline, and generally only have assembly sites. Experts from China State Shipbuilding Corporation suggested that the superstructure construction process and superstructure subdivision installation work should be caused. Full attention must be paid to forming a virtual group process flow or segmented assembly production line for the superstructure as soon as possible. ^[5]