Another Fulmar

[djtil]

Hello.

I'm new to this forum and new to boatbuilding. I have started to build Iain Oughtred's Fulmar. I am trying to figure out how to post images here. This link seems to work, but I can't seem to insert images directly. What to do?

There's not much in the album yet. I will upload more pictures shortly.

http://www.imagestation.com/images/is/community/this_album_button.gif (http://www.imagestation.com/album/?id=4286169239)

[Venchka]

COOL! ;)

http://www.imagestation.com/picture/sraid129/pde2ad092ef02a5bcd312f352754086b9/f7c55864.jpg

Good luck!

Wayne

[DougWilde]

Wayne,

How do you like Rhino?

Doug Wilde

[Corso]

:D Rhino :D , doing the same with the Grey Seal

Djtil: Verry nice, but whats your monitor, a 27" tongue.gif ? im surprised you can work with all the toolbars on.

P.S. for the pics you have to link directly the pic (right click on the pic, select properties, copy the url you see in the properties window, select the "image" button underneath your reply message box, and paste the url in the image popup script box, click ok and you are set)

[ 07-22-2004, 01:11 PM: Message edited by: Corso ]

[djtil]

Thanks for the advice on posting pix. I'll try it later.

Rhino is really nice. Iain's plans are great because he shows the plank lands at each station mold, so I was able to model each plank in 3-D. Then Rhino can unroll the developable surface to give the true plank shape.

My next step is to, hopefully, cut the planks out on the large (6' x 18' bed) CNC router :D at work. I will try it first with some cheap luan on 1 or 2 planks just to make sure that the lines are correct.

[Corso]

What did you use to "vectorize" the lines?

You can even extrude the planks so to have them landing on eachother and see the developed bevel too, check the offsets in an hearbeat, switch from inches to millimeters with no pain and calculate exactly how to scarf and waste less wood possible :D . But thats mostly for fun ...

[ 07-23-2004, 10:47 AM: Message edited by: Corso ]

[djtil]

What did you use to "vectorize" the lines?
My first step was to plot out the points from the plans that represent the inner plank edge at the keel and the upper inside edge of each plank at each station. I then drew a "free form" curve through these points for an edge at each plank.

Next, I used the "fair" command along with the "curvature graph" on each of these lines. The lines were already quite good, so I tried to keep the faired lines within 1/8" of the originals.

With these lines, I started to draw the planks. Starting with the line at the keel and the line for the first plank, I would draw a surface using a line segment between the end points to "sweep 2 rails". Then I would "offset" this surface to the ouside by the plank thickness. With these two parallel surfaces, I would then in a similar way draw in a surface connecting the upper edges. This upper edge surface then would be "offset" downwards by the width of the plank land (3/4"). The outer edge of this new surface would then be the lower inside edge of the next plank.

The process was then repeated for each plank. After all of the planks were drawn, I went back and again "offset" the inner surfaces of each plank by half the thickness of the plank. This gave me a surface at the centerline of the plank thickness that I applied the "unroll developable surface" command to in order to get the flatenned plank shapes. These plank pattern were then exported to Autocad, and will then go through our post-processor (Autolink) to go to the CNC.

I also used the modeled up planks to draw in 1/2" x 3/4" battens to the inside at the plank lands. I am going to use Tom Hill's method to build. I thought this would be a good idea, as it will allow me to check for fit and fairness as I go.

With the battens drawn in, I then drew in section planes at each station. I then was able to get a cross section through the planks and battens where each station mold will go. These cross sections were then used to draw in the shapes of the molds, which were again exported to Autocad. Here I did run into one problem. In exporting the station molds, I wasn't sure what to do with the "curve options" settings, so I left them at their defaults. This resulted in several segments being missed (actually joined into one). Because the original segments were fairly close to colinear, I did not notice this on the drawing. :( I had the parts already CNC'd and set up on the building form before I saw that something was wrong. I had to go back through the process again and make several new mold sections. I just remade the areas that were bad, and cut out and pieced in the new parts.

Boy, this whole process is almost harder to explain in writing than it is to do.

BTW Grey Seal was the first design that I fell in love with, and got me to order Iain's catalogue. I finally decided it was a little too much boat for me to build, as this is my first time and my garage is too small (at least with all the tools & junk). How is yours coming?

Dave

[Corso]

Im always looking for good software to vectorize automatically, but all i found to the moment is garbage, have to do everything manually.
:( I sort of hate Autocad, a lot of what i import there from other CADs ends with problems, i often have to get into big rounds of format conversions to save the time to correct them (im still not sure i save any time that way :rolleyes: )


BTW Grey Seal was the first design that I fell in love with, and got me to order Iain's catalogue. I finally decided it was a little too much boat for me to build, as this is my first time and my garage is too small (at least with all the tools & junk). How is yours coming?
Lets say that im sitting here and waiting for it to come...to me, but its taking its time. First im going to stretch it to 24' (unless SOMEONE really close to me decides she doesnt need a few things from the boat), then there are other minor changes im taking care of toying with it in the CAD, and at last, but not least, its budget and room (will move soon in a new larger house). In the meantime im slowly accumulating the material i need.
Once all this will be done ill send the changes to Iain and ask his opinion and, hopefully, blessing... and then ill start building.