Study On End Launching Of Ships With Slender Underwater Shape

As the development of shipping industry and the increase in tonnage of ships, the safety of large ships and ships with slender underwater shape during ship launching has been paid more attention in shipbuilding community. Especially when some dockyards build large ships in short slipways, a number of accidents have occurred, which lead to great loss to shipyards.End launching of ships with slender underwater shape or ships manufactured in short slipways may cause big block reactions at the end of slipways and even lead to tipping due to shortage of buoyancy at stern. In the thesis, a new technology to overcome tipping by fixing pontoons with optimal size and position at stern is proposed in order to increase buoyancy of ships at stern. The proposed new technology has been successfully applied to launchings of several pure car and truck carriers and proved to be efficient and applicable. The safety problems occurred to the end launching of above-mentioned two kinds of ships can be solved easily and efficiently by using the new technology. When the pontoon is optimized, its size and the position are regarded as variables and its volume is regarded as object function. Requirements on tipping, limited sinking depth of the ship and reactions at the fore supporting points are considered in the design. Sequential unconstrained minimization techniques are adopted to solve for the optimal design scheme; and an optimal code is developed based on MATLAB.As the increase in tonnage of ships and high competition of manufacture cost, the safety and integrality during ship launching have been paid much attention in shipbuilding community. In the thesis, a mathematical model of optimal weight allocation of ship end launching is put forward, and the optimal weight allocation program is developed based on MATLAB, in which adjustable weights are selected to be variables, launching weight is regarded as object function, and requirements on tipping, limited sinking depth of the ship and reactions at the fore supporting points are considered in the design. Again, sequential unconstrained minimization techniques are adopted. Adjustable weights at adjustable places are optimized using the proposed method to maximize launching weight in the condition of safe launching. Therefore, launching integrality is improved, which is great important to shorten the period of shipbuilding.