Re: Traditional Table of offsets, Ft, Inch, eigths – importing to delfship

[John R. Coil]

While the program ably handles matching lines there is an issue with tables of offsets because the points you enter are control points rather than actual points — i.e. it draws the station based on the location of the control points but not necessarily through them. This leads to the model shrinking somewhat relative to what you want.

I have been fighting this very bugaboo too, though to a lesser extent since I’ve been building developed hulls out of the intersections of sheer, chine, and sidewall profiles that are themselves developed BUT the way the program works only the end points in a line are REALLY just where I want them without fudging the control point locations.

To match offsets for a round chine hull I would recommend first inputting your data as indicated and then export a set of offsets based on the model so generated. You may be able to employ scaling on individual waterlines or sections to get things closer but just moving the control points a bit is probably what you’ll be doing before long. Repeat as needed.

Another alternative is to import VRML from a program like Hullform that does draw its lines through the control points you enter (though in the case of Hullform faring a rounded station with more than 4 control points is often tedious slogging). I think Hulls may also draw lines through the indicated points and there is a specific import feature for that program.