A large number of cargo vessels need to carry the cargo in standard sized units, such as fish boxes or sea containers. An early design decision is to determine the stacking arrangement, the number of bays, rows and tiers, for the cargo to be arranged in.

Taking a container ship as an example, we can increase the vessel width by a one container, and then reduce the length accordingly to maintain the same number of container bays. Varying the container arrangement will alter the initial vessel cost, lightship weight, resistance, stability and more.

The aim of this exercise is to create a series of vessels of similar hull shape, with different breadths and widths to carry different arrangements of containers.

·   Use the Sample Design of a container ship as a base boat. C:\Program Files\Maxsurf\Sample Designs\Ships\Containership_1Surface.msd

·   The vessel is designed to carry 640 containers in its midbody, arranged in 8 tiers, 8 bays along and 10 rows across.

·   For a standard 40 ft container allow dimensions of 12.9(L) x 2.52(W) x 2.6m(H)

·   Assume that the vessel displacement is independent of the dimension. This could be accounted for at a later stage by using a displacement, non-dimensionalised by the length x breadth x height.

·   Only account for the number of containers in and above the midbody. Assume the number of containers elsewhere remains constant.

·   Open a parent design

·   Create a series of container arrangements, maintaining the same number of containers, but varying the number of rows, bays and tiers.

·   For each container arrangement;

     Scale the vessel breadth to suit the number of rows

     Scale the vessel length to the number of bays

     Parametrically transform the hull, altering the depth and coefficients to return to the original displacement.

     Save the hull with an appropriate file name.

     Reload the parent design.

·   The design can then be analysed for resistance, sea keeping, cost and stability, so to find an optimised design.

The process could be made far more complicated, accounting for the change in displacement according to the dimensions of the hull, propeller immersion with changes in resistance and more.