Determination of Seakeeping Performance for a Case Study Vessel by the Strip Theory Method

Abstract

The increase of seakeeping performance is of particular importance for car and passenger ferries, service ships in the gas and oil extraction industry and offshore wind power farm industry, as well as for special purpose ships (including military applications). In the water areas of the Baltic Sea, North Sea, and Mediterranean Sea, which are characterised by a short and steep wave, the hull shape has a substantial impact on the operational capacity and propulsion efficiency of the ship, as well as on comfort and safety of navigation. The article analyses selected aspects of seakeeping for four variants of a selected case study vessel, indicating practical limitations of the strip method. The analysed aspects included hull heaving and pitching, added resistance, Motion Thickness Indicator (MSI), and Subjective Magnitude (SM). Experimental tests were also performed in the towing tank. Their comparison with the numerical results has indicated high inaccuracy of the strip method. What is more, the simplified representation of hull shape used in the strip method makes it impossible to analyse the effect of hull shape changes on the predicted seakeeping characteristics. Especially for the case of head wave, neglecting highly non-linear phenomena, such as slamming or head wave breaking, in strip method-based computer simulations will significantly decrease the reliability of the obtained results. When using the strip method, the seakeeping analysis should be complemented with model tests in a towing tank, or by another more complex numerical analysis, such as CFD for instance.

Optimization of ship hull forms by changing CM and CB coefficients to obtain optimal seakeeping performance

“…Thin-ship strip theory [4][5][6] Slender-ship approximation [7] Fourier-Kochin flow method [8,9] Strip theory [10][11][12][13] Potential-flow panel methods based on Rankine sources [14][15][16][17][18][19][20][21][22][23].…”

Experimental Research of the Impact of Ship’s Rolling on the Performance of PV Panels

“…For this reason, some of them, such as handling machines, must be designed with attention to possible swinging of the ship which causes periodic tensions that lead to fatigue damage. In particular situations, for example during strong storms, excessive overload of mechanical devices can occur and threaten catastrophic damage [22,23]. In the case of PV panels, because of their relatively small mass, the effect of the ship's swinging on the construction of the panels themselves, as well as on the fastening devices, is negligible.…”

“…When the wind stops blowing, or the wave reaches regions where the turns into a swell, approximating a regular wave. -pitching (rotational displacements relative to axis y): attention to possible swinging of the ship which causes periodic tensions that lead to In particular situations, for example during strong storms, excessive overload of me can occur and threaten catastrophic damage [22,23]. In the case of PV panels, relatively small mass, the effect of the ship's swinging on the construction of the pa as well as on the fastening devices, is negligible.…”

“…The issue of waving has been discussed in a number of papers, i.a. [22][23][24][25][26][27]. They also give differential equations for the ship's swinging for both regular and irregular waves.…”

The Influence of Selected Strain-Based Failure Criteria on Ship Structure Damage Resulting from a Collision with an Offshore Wind Turbine Monopile

“…Sample photograph of an off shore support vessel (OSV) operating at an off shore wind turbine (OWT) farm [1] Th ese issues are important and have been the subject of numerous scientifi c studies. Safety at sea is very important, therefore research has been carried out on various ocean engineering structures for diff erent purposes and dynamics [4][5][6][7][8][9][10][11][12]. For example, an analysis of ship collisions with 3 types of support structures was published by [13].…”