| SHIPWEIGHT |
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| ShipWeight
is new ! It is used for weight and CG estimation of any ship type
from the earliest time in the design phase, but also for the monitoring
of these parameters during building. |
Using
breakdown structures, ShipWeight divides the ship into weight groups
and records weight, CG and other relevant information. Each individual
group uses a specific estimation algorithm, and the coefficients
used in each algorithm are graphically regressed from user defined
data. ShipWeight includes weight distribution curves, gyradius key values, standard and user-defined reporting, tracking of uncertainty, equipment weight database, weight oriented project comparisons. |
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| Weight
is by far the most important parameter in cost evaluation and production
planning. |
Increasing
demands for stability documentation requires better weight and CoG
information. A heavier ship than the estimate can have crucial effect on speed, deadweight, cost and seakeeping. A ligther ship than the estimate can have crucial effect on stability and require unnecessary ballast. |
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| The
need for weight control To maintain and ensure the important ship parameters and operations such as
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- a reliable weight and center of gravity is essential. Small deviation between real weight/CoG compared to estimated weight always represents a cost for either you or your customer. More significant deviation between real weight/CoG compared to estimated weight can lead to large rebuilding of the vessel or dramatically changed performance, both representing great costs. |
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ShipWeight
is a system for... |
ShipWeight is a computer system for estimating and following up the weight and center of gravity of a vessel. The system is designed to give faster and more accurate estimates, and more structured and more secure monitoring. When the system is utilised in the course of systematically following up weight during the building phase, weights, centres of gravity and other parameters are recorded and structured in such a way as to provide an optimal basis of empirical expirience for estimating weights and centres of gravity in subsequent projects. Weights and CoG can be tagged to sections, areas, diciplins, weight codes etc., and reported according to this. |
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Monitoring The monitoring is done in the AsBuilt module of ShipWeight. A breakdown structure divides the ship into 300 posts in 5 levels. Data for the weight items are entered into these posts. The system is developed to make the monitoring easy. A search dialog makes it easy to find the right post for the weight item. By entering the SFI number or by entering the name of the weight item, the system automatical guides the user to the right post. The user decides in what extent he wants to use the posts and levels in the breakdown structure. AsBuilt projects can be compared with Design projects in a windows-dialog, where you can compare post to post and deviations can be analysed. |
Gyradiuses are calculated for pitch, yaw and roll and for some combinations of these motion modes. A weight distribution curve can be shown graphically, and be exported to both AutoShip and NAPA design systems. It is easy to move weight groups in any directions and see the effect on the center of gravity. Separate databases contains additional information on ship equipment, ship owners, ship designers, and shipyards. A log file automaticly obtains actions by the user to document the work that is being done. |
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The
ship database In each post in the breakdown-structure there is attached an estimation method on the form: Weight = coeffisient * parameters Along with the registration of weight and CoG for a project, parameters of relevance to the ship and estimation method are registered. This establish coeffisients for the methods. When an AsBuilt project is complete all the information is exported to the ship database. When a new project is to be estimated, the information in the ship database is used as basis for the estimation. |
When estimating a new project, uncertainty for each post can either be calculated by the program, or set by the user. Successive calculation is used to calculate the total uncertainty. By using the "most uncertain" function in ShipWeight, the program will guide you to the post where the uncertainty has the greatest effect on the ship. This will help you to use your resources where they are most needed. Context-sensitive help files gives the right help at the right place. |
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Estimation Estimation of weight and center of gravity is done according to the break-down structure. In every post an estimation method on the form Weight = coeffisient * parameters is attached. To get the right coeffisient the ship database is searched for coeffisients from AsBuilt-project. The coeffisients are plotted in a graph. Filters can be set to plot only coeffisients from ships which meets certain criteria. |
Examples of such criteria can be ship type, machinery power, L/B, etc. A regression line is plotted in the graph to help the user select the right coeffisient for the project. When a coeffisient is selected, the weight or CoG is estimated. Like in monitoring, the user can decide in what extent he wants to use the breakdown structure. |
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| Link to BAS engineering. |
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