https://blueheronkayaks.com/kayak/software/software.htm?fbclid=IwAR3raHFDos20XEM6laVN1RJLOYtvlKTXpUK-V5G8Sk2XtyJQVeLcsCtXUIk

"Kayak Design Software
Like many kayak builders before me, having built a few different designs, I began to think about designing one of my own. I was not prepared to pay for a commercial naval architecture package, and I thought it would be a fun project to develop my own kayak design software. KayakFoundry is the result. Version 1.6 is now available for download."

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KayakFoundry 1.6 Features:
Stability Curves
Multiple views for shaping the kayak in Plan, Profile, and Body
Supports 1, 2, or 3 cockpits with independent or shared shapes
Auto-positioned cockpit tracks with changes to center of buoyancy
Resizable/hideable panels
Waterlines and buttock lines
Active Section view shows all section dimensions
Curve shaping by dragging control points
Rubber-banding for multiple control point selection
Keyboard arrow keys provide fine adjustments of control point position.
Real-time calculation and display of all kayak curves and hydrostatic data
Real-time location markers indicate critical hydrostatic positions
Optional auto-roundover of deck at bow and stern
Sliding position line for viewing cross-sectional shape along the length
Unlimited undo/redo
Imperial or Metric units
Bow Left or Bow Right display
Printed stations - adjusted for user-specified strip thickness (sample form)
Printed study drawing (sample study drawings)
Zoom in/out
Optional grid with user-specified interval
Exaggerated curves
A "notes" panel let you record comments and descriptions of the design
Integrated drag predictions using John Winter's KAPER algorithm
Form layout canvas to minimize paper usage
Parameters for the Broze drag prediction spreadsheet