75000dwt Panamax Bulk Carrier General Design

Ship general design is the most important stage and headline. It influences other part design. If a ship design is not good in general design, the whole ship design is not excellent. The paper take 75000dwt bulk carrier general design as a example to demonstrate how to design a ship.The paper explains how to choose particular dimensions of a ship. it deeply influence the ship performance on speed, stability, tank capacity, and general arrangement and determine ship design to be good or not. It is basic and important task to choose suitable principal particular in general design stage. principal particular is determined by technology and economy performance. However panamax bulk carrier size is limited by pier and canal. Suitable principal particular range is small. So basically technology determine principal particular. Economy hardly influence it.General arrangement is an important compositive design. General arrangement directly influence ship usefulness, navigation, safety, structure technology. Double side skin, cabin arrangement ,accommodation height, forecastle fitting and relevant design are key point in general design stage.Hullform lines design is related to ship performance and economy. It influences ship hydrostatics and dynamics,speed, general arrangement, structure design, production technology. It is a sign of design quality. so designer consider to design lines before determining particular dimension and general arrangement of initial design.Calculating and analyzing ship performance. Mainly designers consider calculation in various way including hydrostatics, capacity, freeboard calculation and tonnage calculation, intact stability calculation, damage stability calculation. it decide the ship economy and safety. it should meet design requirement as a floating and sailing sea building .Also economy and safety is long term target when ship is in service.Structure design emphasize hull girder strength, key structure arrangement, local structure optimization. structure design influence ship economy and safety very much. Shipowner hope the ship is more economical and safe also the service is longer, the ship is better. Yet shipyard hope production technology is more advanced, shipbuilding period is shorter, construction rationality is better. So structure design is quite important part in design stage.Feature of this vessel is that it has double side skin in cargo hold region. double side skin. it is the biggest reason that side structure in cargo region damaged frequently.and result in cargo hold flooding, even vessel sinks. single side structure damage often happen at the end of strong side frame. Because corrosion and distortionmake plate at the end of strong side frame split. And water will penetrate. This action happen time after time. eventually structure collapse resulting in cargo hold flooding. The worst condition is that the hull girder break. Setting double side skin have two problems. One is that it make light weight add, the other is it reduce cargo hold capacity. To avoid the bad influence, I put forward several schemes. at last choose current schemes. At first design adopt transverse side frame structure, however, in fact adopt longitudinal structure through calculation. This will reduce much more light weight. To increase capacity, design increase mould depth. depth is not beyond limited scope. If depth is too large, light weight will increase rapidly. Meanwhile bad influence is on stability. Otherwise design reduce top side tank and bottom side tank capacity and increase height of hatch coaming. thus get enough capacity, realize the achieve goal.