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

[Tom Lang]

Hello, Being a very new user of Delft Ship I thought it best to ask this question first rather than spending more time trying to work through the manual. I have three original tables of offsets for a Ferris Steam Ship which I would like to to build into a 1/48 scale working steam radio controlled model. I have the half breadths, heights above base and diagonals. Is it possible to enter this data in Delft Ship and produce drawings from the program? I have attached the three files of the offsets to this request.
I do have .gif files of the drawings of the ship as well but plotting the files to a standard size or scale is very difficult but not impossible. Which route would be the quickest to achive drawings do you think?
Kind regards,
Tom

Attachments:

• Ferris_vG_OfsBreadths.gif
• Ferris_vG_OfsDiags.gif
• Ferris_vG_OfsHeights.gif

[Jesus Cruz]

section 6 of the manual, page 17 explain how to import the lines from a text file, I have use this feature to create dlftship files with very good results althougth still some minor adjustment will have to be done.

[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.

[Peter Edmonds]

Here is another approach.

You will need to key in the offsets in some form at some stage, I expect.

I suggest you set up an Excel worksheet, to accept 3 cells (feet, inches, eighths) for each dimension. You can then covert these to another cell that takes sum of (feet * 304.8 + inches * 25.4 + eights * 3.175).

You may wish to copy these mm offsets to other worksheets, arranging to suit your move into DS; saving the sheet as text tab delimited.

You may also want to do another transformation to go from ship size to your model size by dividing all ship offsets by scale factor (48 or its reciprocal in your case; change the factor if required for another scale).

If you are going to build a block or similar model, you may not get value by going through a lines manipulation program. You could just mark out waterlines on planks, with or without cutting to profile before joining the planks into blocks. Sortware would, of course be advantageous if your target plank thicknesses don’t match the scaled waterline spacings.

I won’t go into a discourse here on hull model making.l However, if you are looking at using your text file(s) from Excel as software input, the smart thing to do is lay out your “output” sheet(s) of Excel to suit the input requirements. See current free DELFTship manual (3.2, 2006. 07 section 6.3 Table of Offsets pp 19 – 22)

We await developments.

I think the right way would be to import offsets in any CAD program as complex curves with a text file and make sure these lines do resemble the sail-body-plans. After that it is a matter of exporting X-Y-Z coordinates of the curves and importing them into Delftship program. It should work.

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