PIAS Manual  2021
Program for the Integral Approach of Shipdesign
Shift Frames (Lackenby)

This action, available from [Hydrostatics]→[Shift Frames (Lackenby)] or with the keys <Alt><H><S>, performs a Lackenby transformation on a single solid: by scaling frames in breadth and height and shifting them forward or backward, the solid is transformed to meet specified main particulars. This transformation is also available from the Fairway main menu, see Shift frames (Lackenby). Please also confer Hints for and backgrounds of the transformation process.

action_lackenby_800.png
Transforming a hull by shifting its frames.

In the right-most column of the action panel the design main dimensions are listed as configered in [Main dimensions (design) & hull coefficients] and other particulars derived from the initial shape of the frames. Left of it is the column of editable target values; a change in any of these causes the solid to be transformed accordingly. For convenience, the values from the right-most column can be copied into the fields of target values by pressing the button [Copy initial values from solid].

Note
If exact target values are not available, it is practical to "scroll" towards a viable solution using the mouse wheel and visual feedback.
Attention
Because this transformation shifts frames to new positions, you may want to apply [Systemize polycurve names] to update the names of frames according to their new position.

If the project is configured to make use of a target sectional area curve or SAC (see General Fairway settings) then this SAC is transformed as well, and some additional options become available in the action panel, as discussed in When designing with a target SAC.