The front of the ship is called the fore or bow area, and the aft area is called the aft area. This is also called the tail but is more specific. Stern essentially refers to the aftmost section or structural area of ​​a ship relative to its overall length. Simply put, it’s similar to what you’d see if you stood directly behind the ship and looked forward. The origin of the word Heck is unknown. At the same time, some claim that this came from a distortion of the word “stiarne,” which in ancient Frisian and Saxon implied a rudder. Many argue that it is based on the literal meaning of the word “star,” meaning serious and merciless. 

However, some experts believe that its origins date back to the Viking Age of the 8th and 9th centuries, when it was, they claim that in an ancient pre-English language, maneuvering or maneuvering was called Stila or stir. This later evolved into the English “styrne” and eventually “stern. “This makes sense since the rudder, the main device for steering and maneuvering, is housed under the stern and also attached to the stern frame. In a more technical sense, the term refers to the structural area or section associated with the installation of a rudder or propeller. This is a characteristic of the empennage post, which is the most important structural element of the empennage.

Function and Significance 

Like other structural elements, the stern is an integral part of the hull structure. This ensures that the rear fuselage volume is closed. Additionally, it affects the propulsion and hydrodynamic behaviour of the following vessel. So what is a wake? Simply put, the overall effect on the water behind a ship includes the behaviour of wave patterns, currents, eddies, and currents in that particular area. The ship’s wake behind the stern, or these effects, have a significant impact on the ship’s propulsion efficiency, as they affect drag. As is well known, the greater the drag, the lower the hydrodynamic efficiency of the ship. Therefore, the shape and placement of the stern structure are critical to the hydrodynamic efficiency of the hull. Imagine you have a flat, box-like ship with no defined stern shape, like a barge with the stern of a military frigate.

Which One Has Better Followability and Speed Characteristics Necessary For Propulsion?

Apparently, it is the latter. Thus, depending on the type and design of the ship, the stern is designed according to the subsequent flow behaviour. Furthermore, the stern has the major responsibility of absorbing the effects of loads and vibrations from the rudder, propeller, and associated shafts and accessories.

Types of Sterns

Sterns can be classified into three main types based on the shape of the upper surface of the stern structure: elliptical, cruiser, and also transom. In summary, elliptical tails were common in the 19th and early 20th centuries. When viewed from the above, the deck line associated with this sort of stern shape appears to resemble a closed oval. When viewed from the side, the oval tail curves upward from the vertical at the rear. In the old days, when ships were built of wood, a series of wooden panels ran upwards from the bottom and curved toward the corners to form the outline of an oval stern. 

The curved end of the oval stern extended above the ground aft. There was plenty of space in the rowing area. The stern of the cruiser is thought to be a modification of the oval stern. However, unlike an oval rudder, it is contoured and designed with a lower curved edge. This means the rudder is completely below the planned waterline. Therefore, it has relatively good resistance properties.

Characteristics

It is also aesthetically pleasing and improves subsequent tracking characteristics. The Trans Am is the most common choice for most cargo stern ships. It has the simplest structure, with a flat section from the deck to the waterline. You can think of it like the stern ship of a cruiser, with a flat section suddenly cut away from the stern ship. Although it does not have a curved profile like the two above, it does provide greater flow separation and prevents strong reverse waves and eddy formation. Other types of specialized stern ships that are improvements to the above include the raked stern ship, scoop stern ship, bustle stern ship, or, in the special case of Queen Mary 2, the Constanzi stern.

Design And Construction 

Ships may be supported by beams for all practical purposes. Therefore, in terms of bending or longitudinal bending forces, the greatest bending stresses tend to occur in the anterior and posterior regions. The Figure 8 area is also the area that is susceptible to being hit or hit. Additionally, this area must also withstand loads from the rudder, propeller, and other accessories. Therefore, the rear part must be significantly reinforced.

Lateral and longitudinal reinforcements are installed throughout the plating. Plating the aft area, including the stern, requires larger dimensions. High-quality steel grades, such as high-strength steel, are often used. The rear type also affects placement. The stern of the cruiser features a cant frame placed along the perimeter of the shell and welded between the deck and floor. Cant beams welded to the deck cross members provide additional support to the deck? However, a cant beam is not provided at the transom stern. 

Reinforcements

Horizontal and vertical reinforcements reinforce the flat back plate. All rears feature heavy, solid floors and centerline beams. It is also possible to attach horizontal and vertical members to the plated parts. A very important feature of all hedgerows is the aft frame or aft strut. The stern frame is the lower member, which extends upwards some distance from the keel. It is a structural frame that runs like a spine, providing additional support and strength to carry the loads from the tailstock and rudder that are connected to the frame. Previously, these frames were cast and attached to the outside of the rear skin. However, these days, they are welded to the hull structure. 

The structure of the stern frame is based on the stern and rudder type. Make sure there is enough clearance between the rudder, propeller and stern frame. Streamlined to avoid hydrodynamic problems such as eddies and swirls. Horizontal bars and stringers often support them for additional reinforcement. The dimensions of this frame vary depending on the type of ship and rudder. The rudder and propeller are connected upwards and often remain structurally continuous with the bottom of the stern plate.