from drawing to dxf

[jonnyb]

hi there.
Im a novice with CAD, (I use Qcad) and wonder if there exist any program which can make splines from a drawing. This drawing is a 1905 Hull-drawing of a very late model of Colin Archer. (one of his last ones) I started to do the splines by hand but found out that it was not very accurate.
any clue?

[Guest625101138]

Jonny
I am not going to go into the legality/morality of copying a design. That is for you to work out.

If you are interested in boats you can get a free download of DelftShip that is nice to use for drawing hull surfaces.

You start a new model and set the longitudal points to the number of splines; I think it is 19 or 20. Set the number of points in the vertical direction to say 8. This should enable close conformance to the drawing. You then set the size of hull you want, length, beam and draft. Click on OK.

Once you get to this you will have a starter hull that looks a bit different to drawing.

Expand the bodyplan view to full screen, right click in the window and you will get an option to load a background image. Jusy load the image of the hull. You might have to scale the image of the hull drawing to get it to roughly align with the starting hull - it does not need to be exact because you can move the whole lot later. Also the image has to be jpg or bmp format not png.

Once they are similar size you just pull the sstarter model splines to the same shape as the drawing. You should also set each spline equidistant, as the starter hull will have the points on each spline slightly offset longitudinally. THe left and right mouse buttons are very useful for moving the image around and zooming in or out. It will be tedius but just a bit of patience.

A person experienced with Delftship could do the copy in about 20 minutes. But it could take you a couple of hours as you will need to learn Delftship. If you hit a roadblock just make another post.

You would probably find there are better designs around but that is just an opinion. Depends on what you want it for.

Rick W.

[jonnyb]

thanks rick. Ill give it i try.
(im not a laywer, but making an electronic copy of a boat 102 years old seems to be outside european copyright laws (25 years for picture and 75 years for written text if Im correct)

Jonny

[Raggi_Thor]

Also remember that boats at that time usually did get a small correction near the ends when they where lofted. Designers used to draw curves that couldn't be built, but the builder would give the hull a little less curvature near the end in the lofting process.

[jonnyb]

This is actually a very interesting comment. I havent found any comments to Mr. Archers loftsmen or his foremen (like a work description etc. It could be lost in last 100 years but I doubt) Only way to find any change from drawing to finish result would be to find this boat)

[Raggi_Thor]

Hei, forresten

I can't say this was "standard procedure", but I found a note about it in the museum in Larvik (Archer's home town) many years ago.

[Guest625101138]

Jonny
I believe you are correct about the copyright. Here is my effort to reproduce in a more useful form. It took me longer than 20 minutes. There are a lot of stations so quite a few points and you get eye strain trying to work over the original.

The drawing is a bit rough but a reasonable reproduction of the original. I would normally spend more time fairing things up but the fbm file is included if you want to keep playing with it.

Rick W.

[Raggi_Thor]

Nice work Rick.
Is it possible to have a sharp corner at the lower, aft, end of the keel? and a straight stern to hang the rudder?

[jonnyb]

Thanks Rick.
Very good. This is actually my plan: This boat is around 40 feet long. My plan is to make a 2 meter model in playwood to see how it would look like in real.
This is a almost similar model. (enclosed picture) i think the stern should be more like this this. (raggi_thor is more of an exptert than me) Im just a farmer playing around with boats. :-)

I called seafarers museum yesterday and ask for a electronic copy but they didnt want to share with me. :-( Im pretty sure that this boat is far outside copyright. (its 75 years after death of author for books which is the most strict in EU).


Jonny

[Guest625101138]

Raggi
I expect Johnny to add that detail. It was a tedious hour or more and my eyes were straining.

Rick W.

[Guest625101138]

Originally Posted by jonnyb

...... My plan is to make a 2 meter model in playwood to see how it would look like in real.



Jonny

Jonny
If you download Delftship you will be able to open the model and move it around as a 3D image. It is similiar to a model and and much faster. Also easier to modify.

At 40ft this would be a very big boat and very expensive. Very heavy to handle, slow and poor pointing ability. If you are thinking about actually making a boat, there are better designs around.

Rick W.

[Raggi_Thor]

Originally Posted by Rick Willoughby

Raggi
I expect Johnny to add that detail. It was a tedious hour or more and my eyes were straining.

Rick W.

You'r welcome

[Raggi_Thor]

They build a few "Colin Archers" in Norway still, but they are not based on the rescue boats, but on lighter pleasure and racing boats, and sometimes made even lighter now, so they look traditional, but has a (little) more modern displacement.

[jonnyb]

I just made a check on FINN (mabye the biggest inernet search for boat in Norway) I found 18 more or less "colin archers" for sale.
(http://www.finn.no/finn/boat/used/browse1)
so still popular but as you said: Not a fast boat.

[jonnyb]

hi,
ok, this is probably very boring for your computer only guys. but I scan that dxf file and made the tracing in qcad, and aftewards run the whole stuff in a plotter in size 1/5 and made a plywood version. (old fashion way of doing stuff ehh?)
My next question is mabye easier. I want to make the skin with oldfashion lapstrake.
How should the garboard and planking? any idea?