Orca3D News

Tuesday, June 30, 2015

Managing Multiple Hydrostatic and Stability Conditions

It's often useful to be able to analyze multiple conditions when doing a hydrostatics and stability analysis. Each condition might be a different sinkage, weight, center of gravity, or some combination of these. For simple variations such as a range of sinkage values, you can just type the range into the appropriate field. For example, for sinkages of 1.00, 1.25, 1.50, and 1.75, just type the values into the Model Sinkage field, separated by commas. In this case, since the spacing is constant, you can use the ellipsis shorthand:
1.00, 1.25, ..., 1.75 
The spacing between the first two values is used until the value after the ellipsis is reached.
If your conditions include one or more based on weight and CG (free float), AND one or more based on Sinkage, Trim, and Heel (fixed plane), then you need to use Custom Conditions.
Check the "Use Custom Conditions" box in the Hydrostatics dialog to see the list of Custom Conditions in a grid. Initially, it will be populated with any conditions that were created by entering a weight/CG or flotation plane(s). You can edit the values in the fields, name the conditions, turn them on and off, and add additional conditions. You can also specify which field should be used to sort the results (by default they are sorted on displacement).

By extension this allows you to manage the weight variations caused by numerous catalog options, and their impact on the stability: auxiliary genset, sail furler, radar antenna on the mast, tender and crane on the flybridge, etc., or simply to quickly check different design hypothesis.