Why Side Scuttles are Round?
Side Scuttles are provided on the ship’s side outer panel, superstructure and deck outdoor wall. It is a structural opening on the hull, it’s a circular window which can stand and transmit certain structural forces of the hull, and it should be watertight. Generally consists of a main window frame, a glass platen, a storm cover. The side scuttles, together with their glass and porthole covers (storm cover), shall be of a solid construction and shall be capable of effectively closing and ensuring watertight.
There are 3 types of side scuttles:
Type A, heavy type side scuttles.
Seagoing ship: Allowed side opening position that under bulkhead and freeboard deck but above loaded waterline where also required watertight and airtight.
Type B, medium type side scuttles.
Passenger ship: the side of the bulkhead or superstructure above the bulkhead deck or freeboard deck;
non-passenger ship: sides and ends of the first superstructure on the freeboard deck.
Type C, light type side scuttles.
Passenger ship: side and rear sections of the superstructure above the first and upper layers above the bulkhead deck or freeboard deck;
non-passenger ship: side and rear sections of the upper cladding above the first superstructure above the ship’s freeboard deck.
Why are the portholes round? This is because, according to the mechanical principle, a circular structure can withstand stresses such as pressure and shear more than other shapes. When the ship is sailing, it will be affected by wind and waves, so the porthole will be subjected to a large wind and wave force; at the same time, the effect of the wind wave and the change of the load will cause the ship to deform. The force of these deformations will directly affect the outer plate of the ship, especially It is the outer panel below the main deck.
If the porthole adopts a rectangular or diamond-shaped opening, the deformation stress will easily collect on the corner of the rectangle, resulting in stress concentration. When the stress of a certain angle exceeds the allowable stress, the porthole angle tends to be deformed or broken, which will make The strength of the hull structure is greatly reduced and affects the safety of the ship. The circular porthole is different. When a part of it is subjected to an external force, it can evenly distribute this external force to various parts, which can largely avoid damage caused by excessive stress concentration at a certain location. The phenomenon.
At the same time, according to the mathematical knowledge, we can know that the circular and other shapes of the same area, the circumference of other shapes are longer than the circular shape; on the contrary, under the same circumference, the circular shape is larger than any other shape. This means the same amount of construction, and the round portholes have a greater amount of light. In addition, the circular opening is easier to construct; the shorter the circumference, the better the sealing effect. In addition, the circle looks more beautiful and generous. Therefore, the ship’s portholes are designed to be round.
