Drafting VS Freeship VS Rhino (help on keels)

[Moose]

I'm still crunching away at YDS lesson 1. It's not a long one but it inspires a lot of revision because they just want me to draw my ideal boat. So basically, I could fiddle with it forever... Anyway, on to the meat of the question: I've been delaying sending in a design for critique because I want to get in the habit of sending in assignments both on paper (which I seem to have a knack for) and in CAD (which I definately DON'T have a knack for.) I got a reccomendation to try doing conceptual work in Freeship until I know Rhino a little better, but I can't get either program to come close to what I've drawn, especially in the keel area. dragging control points around doesn't seem to work and the Keel Wizard definately doesn't work because it seems geared exclusively to fin and other modern keel shapes which I don't want. So I suppose my question is, anyone know what to do about this? It's driving me up the wall, and I'm considering just dumping my computer off the wharf....

[Lucky Luke]

Hi Moose,
I don t know if I can help since I do not clearly understand your problem (and I don t know about freeship which works on a different math than other NA programs).
However, if I get it right:

Rhino is not designed for hulls, although it can do it. The NA program for that is fastship, which works using NURBS the same as Rhino. Effectively, besides the hydrostatic calculations, fastship has a better capability in moving whole area or whole path of control points. It is a very bad practice to move moints one by one, and has to be kept for detail adjustments.

Then, guessing that freeship does approximately the same job as fastship (and Autoship, aso...) I would say that you effectively must do your primary suface with it. After that, Rhino is wonderful for slicing, cutting sufaces one by another, extruding along splines, crating sufaces between splines, aso... but you will find that it more adapted to the superstructure than to the hull.

Concerning your question about the keel modelling, I understand that you want a classic long keel and not an attached fin keel. Fine: just work with one single surface that will do the hull and the keel, all at once. You will need to concentrate rows of control points around the garboard area, and perhaps have difficulties (I don t know which design you are working on) with some angles (or knuckles) you may want to introduce in the profile drawing of that keel.

Transom and perhaps bow may then better be done by Rhino.

Anyway, although you amusingly describe yourself as senior member on this forum...at the age of 27!, may I say that you WILL have to get into CAD (although you must not forget the hand drawing, ever!), and become familiar with all these (expensive!!!!) programs. 3D modelling offers quite wonderful possibilities, far beyond hand drawing, and once you get used to it you will like it, and it will become a sort fo second nature for you to make virtual objects, boats or else.

Good luck!

[Moose]

Luke, thanks for the help! In case this clarifies things, the design is a 29' gaff rigged sloop w/ staysail. dimensions are 29'9"LOA, 22' LWL, 8' beam and 5'6" draft. The hull profile as drawn is similar to LFH's Nereia, but with a shallow spoon bow w/ 4/ sprit and a straight run down about a 10 degree angle to the rudder which makes up the keel. Everything looked good when I drafted it manually, even to the point of starting to develop a midsection and stations that look promising. Disregarding my difficulty with Rhino (the difficulty is that I can't really do anything with it) my problem in Freeship is that without using the attached 'keel wizard' which will happily produce a fin keel with any one of many airfoil shapes, it seems to only allow me to drag my control points one by one, and the model does not seem exact enough for me to do that and end up with the same design. I'll see if I can find a sample copy of Fastship and play around with that for a while...

[Moose]

Oh, and the 'Senior Member' just appeared under my name one morning, apparently after having made 100 cranky posts in the bilge...

I just haven't thought of something witty to replace it with yet!

[Mark Van]

I've been using DesignCad for years. It is a cheap general purpose cad program, the one I have does 3-d modeling and 2-d drafting. You have to know how to draw up a set of lines by hand and also how to do the displacement calculations the old fashiond way, since it doesn't have the specific tools for hull design. You don't need a planimiter, since it is easy to find surface areas of the stations. You also don't need the stations at andy specific distance apart for calculations. It is still 100 times eisier than drawing on paper. Below are some examples. (also a shameles show off of my new design.)
http://markvdesigns.tripod.com/sitebuildercontent/sitebuilderpictures/.pond/mv283dview1.jpg.w300h156.jpg
http://markvdesigns.tripod.com/sitebuildercontent/sitebuilderpictures/mv28studyplan.jpg

[Moose]

First, nice design! Second, thank you very much. I'll try designcad out as well. It seems like you are describing something that's very similar to the mechanics of drafting by hand, and that definately seems like what I need to start with!

[Andrew]

I've just started looking at both Rhino and FreeShip. Can anyone tell me how the import back and forth between them?

Thanks much

[Bruce Taylor]

Can anyone tell me how the import back and forth between them?

Import/Export in IGES format.

Moose, a number of months ago I threw together a few tutorials for FREE!ship. There's one on shaping simple keels:

http://www.imagestation.com/album/pictures.html?id=2115454673

Centerboards:

http://www.imagestation.com/album/pictures.html?id=2115488028

Masts:

http://www.imagestation.com/album/pictures.html?id=2115307029

and Sails:

http://www.imagestation.com/album/pictures.html?id=2115249706

[Moose]

Thanks Bruce, this should keep me occupied for a while!

[paladin]

What is YDS?

[paladin]

What is YDS?......oops....figggered it out, it's McNaughtons version of Ted Brewer's Yacht Design Institute.....

[Bruce Taylor]

Note that FREE!ship is no longer available. The program has been replaced by DELFTship, which comes in both a free and a "professional" version. The free version is missing a few functions that were available in FREE!ship 2.6. The DELFTship webite also offers a free demo for the professional version. The demo includes all the standard features (stability analysis tools, for example) but limits the user's ability to print or export his work.

www.delftship.net

[Andrew]

Bruce, thanks for the help (and the tutorials).

[michigangeorge]

It's driving me up the wall, and I'm considering just dumping my computer off the wharf....

DO IT AND YOU WILL DESIGN BETTER BOATS! I'm not trying to start something here but there are plenty of us still around who remember what a boat should look like and I have yet to see it very often when done by CAD. The drawings and the finished boats look sterile and lacking in both detail and artistry. The response always seems to be that you just cannot spent the time to hand draw anymore- gotta make $$$. Well, if you want $$ become a doctor- yacht design should be an art. Why do we keep seeing the same old designs by Herreshoff, Culler, Nielsen, Peterson, etc on this forum and in WB? Because none of you younger guys have come up with the same type of beauty and the aesthetic of detailed yet functional parts. My point is that although there are plenty of good new boats being designed, there are few that are truly special and will have that lasting desireability of a Herreshoff 12 1/2. The very drawings themselves brought joy when looking at the intricate detail, line quality (dark,light,thick, thin) and I regard it as one of our higher art forms. You can't say that about what is spit out of a computor printer. I recently read an article over on the Yacht Design Web about the dirty little secrets regarding the limitations of CAD. I don't pretend to understand all I read but I am certain that the old way was better- but then you would not make $$$ and that is what this country is all about, eh? Just a thought from one old dinosaur....

[Mark Van]

I got into a similer discussion with a guy who insisted that you can't design a good looking boat with a computer. He was cruising on a Stone Horse, so he had good taste. He said that he rowed around my boat, and thaught that it had a beutifull shear line from all angles. I told him that I designed that sheer with a CAD program by drawing the stem, midship section, and transom, and letting the CAD program draw the sheerline. I looked at it and decided it looked good, so left it that way.

I think that if herreshoff had access to a good CAD program, he still would have designed masterpieces, using the computer. Designers who designed artistic masterpieces usually have had LOTS of experience, and since good CAD programs haven't been around very long, there are not very many experienced designers that use it exclusively.
One more point with my rambling post. There used to be a big market for artistic masterpieces, there isn't much any more. Look at how popular Bayliners and Carvers are.

[paladin]

Yup, Mark.....there's lotsa cheap boats out there that were not purchased because they were beautiful......but cheeeep, and some dude had money burning a hole in his pocket and wanted to go Yotting......but thankfully there's folks also who will not purchase the boat until they find their dream....

[Chris Ostlind]

This isn't about computer driven design at all. Any thinking person knows that the computer is simply another tool and it does exactly what the designer says it should do.

Mark's comment is spot on, though he left out the intuitive fact that he described a set of lines for important elements of his boat design from experience, from feel, from knowing how his tools would likely respond, once put into motion.

Computer designed boats have every bit as much character as do boats drawn on tables with T-squares, triangles and a set of curves. Or, do the gathered readers believe that the advent of drafting machines irreversibly changed boats forever when they became popular for traditional, table-bound draftsmen?

Come on guys… get over it. There are unlimited methods for the creation of beautiful boats. Nobody and no technology has a lock on the process.

Perhaps we should all go back to hacking away at freshly felled logs?

Chris

[Mark Van]

The Hinkley picnic boats are an example of a modern boat that is beutiful. It has classic styling, and it is a very artistic design. I think it is a modern masterpeice. I am pretty sure that it was designed entirely on a computer. I am pleased that there are enough people with taste (and money) to buy them so they stay in production.

[Lewisboats]

As of 8:00 am CST, Freeship is still available to download from Sourceforge. Just Google freeship and click on one of the download links.

Steve

[TR]

Mark,

The original Hinckley Picnic Boat was drawn in 1993, and all drawings were done by hand. Though we did have computers in the Bruce King office, for many years they were only used for fairing hull lines, hydrostatics, weights, and structural engineering. The changeover in that office to 2D drafting on the computer was sketchy and incomplete even in 2001 when I left.

Currently my work is (wild guess) 90% computer modeling, rendering, CAD drafting, and engineering. The other 10% might be hand drawing, which is mostly freehand sketching with a tiny amount of hand drafting.

That being said....good and bad art can be produced in any medium. Compared to hand drawing (IMO) 2D computer drafting (in AutoCAD) is slow and very tedious. I think this is a combination of operator incompetence and software limitations. On the other hand I find 3D modeling (in Rhino) fantastically powerful, quick, and tremendously useful.

All the best, Tad

[Lewisboats]

It took a long time but I finally got the keel right on this. I did something like the way Bruce explains but a bit backwards from his method. I inserted points at the correct half distance from the centerline, joined them then deleted the faces, extruded the edge down then shaped the keel in profile and extruded it back to the centerline. Seemed to work better for me, but then my thought processes are kitty wampus anyways:D .

Stevehttp://angelfire.com/ego/lewisboatworks/Stuff/DBLinesplan.JPG

[Mark Van]

I have been using DesignCad (2-D and 3-D) for years, and I don't find 2-D drafting very difficult to do, much easier than drawing by hand. I haven't done any serious hand drafting since my architecture class in high school. The problem with hand drafting is that I am not a neat freak, so the drawings come out smudged and sloppy.

I have looked at the AutoCad manual quite a few years ago, and it seems like a much more difficult program to learn, probably because it has lots more features that aren't really needed.

I do the initial preliminary sketch on typing paper, and I usually do quite a few of those before I'm satisfied. When I get to the computer, I am pretty sure what I want, so I don't use the computer program to manipulate the design, just to draw it and do the displacement calculations.

[garyspear]

guys is there a way for the complete newbie to learn to use cad for boat design. I have freeship and have no idea how to use it. I thought that I would use outreds CY as a learning project. I got points but so it looks awefull. If you did get the hull how do you fit a super structure bulk heads and the like. I have used turbo cad in the past but cant figure out at all how to get this to work.

Where does one start???

[paladin]

I doodle a set of lines to what I think looks good, then change it to what the client wants, and try to balance the two together.....then we start with all the calculations to see if we really have the space to accomplish what we have in mind....a pencil and eraser are the easiest tools at this point....then if all seems to fit.....the computer can do the calculations about as fast as I can today, and I still do all the drawings by hand....