| The ballast water plays a vital role in the safe navigation of ship. However, improper treatment and free discharge can cause catastrophic damage to the ecosystem and marine environment. When none of ways can completely solve the problems brought by ballast water, the idea of no ballast water ship comes out. At present three design methods of no ballast water ship have been recognized: Monornaran Hull design, V-Shape Hull design and Through-Flow System Hull design. For the sake of solving the problems brought by ballast forever, this paper firstly combines V-Shape hull with monomaran hull and invents a feasible hull line for small and medium ballast-free bulk carrier.In this paper, the line design method of no ballast water ship is studied first. With the35000dwt bulk carrier as mother ship, the width of design ship is determined by the relationship of concave area and deadrise, which is based on keeping the mid-ship section area under the design waterline equal to the mother ship and ensuring the same displacement between design ship and mother ship. Then, through repeated modifications and smoothing, the preliminary design of hull lines can get by establish design ship model in3D software Freeship.Due to the complex design ship form and control variables, the lines are rather hard to smooth. In order to obtain good performance of no ballast water ship, CFD numerical simulations are used to help optimization the ship hull form and resistance performance. The calculation results show that, the pathlines around ship and resistance performance after the modification achieved the desired effect.Then the paper makes general arrangement design and structural design for design ship. The ship fuel oil tanks are moved to the middle position after taking into account the no-load floating condition in general arrangement design. The inner bottom is set as plate form in structural design when considered the effect of actual use. At last the lightship weight and center of gravity of design ship are estimated through the comparative method. After the calculation of floating conditions and the check of stability which used to verify the feasibility of the design, it is easy to see that the design ship don’t need ballast water in no-load condition and have the same displacement with mother ship in full load condition. And the design ship have better stability than mother ship both in no-load and full load conditions.In short, the research of this passage shows that the method of combined V-Shape Hull design with Monornaran Hull design is feasible, and provides references for the follow-up study. |
