akaz456
26.04.2021 22:21:09
A single wide plate which replace two narrow plates in adjacent strake of a ship. Stringer: A horizontal stiffener fitted along the ships' side or a longitudinal bulkhead, in order to provide strength and rigidity.
See full version: What is girder in ship construction
A single wide plate which replace two narrow plates in adjacent strake of a ship. Stringer: A horizontal stiffener fitted along the ships' side or a longitudinal bulkhead, in order to provide strength and rigidity.
Furthermore, how is a ship constructed? The wooden ship was constructed on a building berth, around which timbers and planking were cut and shaped and then fitted together on the berth to form the hull. The berth or slipway from which the vessel is launched is an assembly area, rather than a ship construction site.
Accordingly, what is the purpose of girders in the tank?
Draft: The distance from the waterline to the bottom of the hull. AKA: how much of the ship is physically in the water. Knowing this will allow the crew to determine the minimum depth of waterway the ship can safely navigate.
Plus I believe a wreck dive is all the more special when you know what you are looking at, for example what at first glance may appear as a mundane, barnacle encrusted piece of metal may to the educated observer be a lot more fascinating….
Forward: Facing or travelling from the stern to the bow [links]
Commissioned: The date the ship enters service, when launched they are often empty shells but are fitted out once on the water to allow space in the shipyard for new constructions. here
This is exacerbated when the wave crests are at the ship’s ends and have a wavelength comparable to the ship’s length. here
Plank fasteners are typically pushed or screwed into floor timbers. Floors ties the ship’s bottom to the keel and help to keep the ship’s bottom from sagging. [links]
When a continuous frame is loaded, it generates a series of positive and negative moments in the beams; the moments on the top faces near the joints/supports are known as hogging moments, while the moments in the center bottom region of the beams are known as sagging moments.
For example, consider a simply supported beam loaded with self-weight, with zero bending moments at the support sections and maximal positive bending moments in the intermediate section. This is also known as a sagging moment.
Hogging moment is the instant that causes a beam to concave downward. It is regarded as a negative event.
Another wave-excited hull vibration that can produce significant stress is known as springing. The cause of springing is resonance between the frequency of wave encounter and a natural vibratory frequency of the hull. Slamming and the consequent whipping can be avoided by slowing or changing course, but springing is more difficult to avoid because of the wide range of frequencies found in a typical sea state. Fortunately, springing has not been identified as a cause of any known structural failure. here
Adequate calculation of such dynamic forces and their consequences also requires large computing resources, and hence it was not seriously attempted until about 1980. Major progress has been made, but techniques still have not been reduced to standard design practice. [links]
The traditional ship hull structure consists of a keel, transverse frames, and cross-ship deck beams that join the frame ends—all supporting a relatively thin shell of deck, sides, and bottom. This structural scheme, which became prevalent with European ships during the Middle Ages, has continued into the age of steel shipbuilding. However, it has a significant drawback in that the frames and deck beams contribute nothing toward resisting longitudinal bending. Frames that run longitudinally do contribute to such resistance and thus permit thinner shell plating. This scheme of framing is strongly favoured in applications where weight saving is important. However, longitudinal frames require internal transverse support from bulkheads and web frames—the latter being, in effect, partial bulkheads that may extend only three to seven feet in from the shell. This requirement obviously reduces the weight advantage of longitudinal framing but not enough to negate the advantage entirely. Web frames also have the drawback of interfering with some uses of interior space, and as a consequence the simple transverse system of framing continues to be employed in many ships.
Interactions between waves and hull also may occur in a dynamic mode. An obvious example lies in the impact between moving wave and moving hull. Generally, the results of this impact are of small consequence, but the slamming that can occur in rough weather, when the bow breaks free of the water only to reenter quickly, can excite “whipping” of the hull. Whipping is a hull vibration with a fundamental two-noded frequency. It can produce stresses similar in magnitude to the quasi-static wave-bending stresses. It also can produce very high local stresses in the vicinity of the reentry impact.
The simplest structural description of a ship is that its hull is a beam designed to support the numerous weights that rest upon it (including its own weight), to resist the local forces produced by concentrated weights and local buoyant forces, and to resist the several dynamic forces that are almost certain to occur. As with any structure, stresses at all points must remain below the limits allowable for the construction material. Likewise, deflections both local and overall must be kept within safe limits.