Hello all amateur designers,

I know that a few of us are trying to make their first steps with CAD using the free!ship programm.

Here is a link to a tutural that helped me a lot. It shows the basic steps from the start over making the chines, fairing the lines to get the developed panels.

http://www.boote-forum.de/showthread.php?t=122242

It is written in german, but with a little patience you will be able to learn a lot from the sreenshots alone. If you have absolutly no idea what is meant you can post your question here on this thread.

the best method learning is to have your own freeship running the same time with the tutural so that you can see what happens when you push a button.

I will make some own posts too, to say what worked out for me. There are some tricks that makes it much easyier to get a fore-and aft symetrical- as well as a developable chined hull.

Best Regards, Michel

Thanks for that. It was useful. (Ich spreche Deutsch, aber nur ein bisschen)

I’m not sure what’s going on when the curvature plot of intersection lines is shown (Frames 7, 8, 9). When I select the appropriate longitudinal line, nothing happens, so I must be missing a step? Also, when I do select this feature, I get what appears to be a strange, anomalous error, for the hull seems to fair. See the attached jpeg of a design I’m working on.

Prost,
Rick

Rick - 14 December 2011 10:26 AM

Thanks for that. It was useful. (Ich spreche Deutsch, aber nur ein bisschen)

I’m not sure what’s going on when the curvature plot of intersection lines is shown (Frames 7, 8, 9). When I select the appropriate longitudinal line, nothing happens, so I must be missing a step? Also, when I do select this feature, I get what appears to be a strange, anomalous error, for the hull seems to fair. See the attached jpeg of a design I’m working on.

Prost,
Rick

Hi Rick,

mark just the horizontal (red) chinelines if you want to check the hull for fairness, not vertical ones. if you have already converted them to be a chine, all sections of the buklheads will be straight automatically.
click every part of it to e yellow and then “controlcurve”. The line will become violet now and can be marked (yellow and violet) and cecked for fairness after deactivating the controlnet (points and red lines).

Do yourself a favor and try to design a (fore and aft) symetrical dory as training first with na little “V” in the bottom. 5 points longitudial and 3 points vertical. When you are get used to do the whole operation,  you will know what you are doing and can start your real proa.

I know that you want to see your dreamboat rising, because you can see it in your mind,
But it will be faster and less frustrating if you choose a very simple hullform at the beginning.

I have worked out a few trickst to support proa hull development but I need some time to collect them and to write them down, making understandable sentenses.

Did you switch the language to german for the first steps or are you looking at the symbols?

Good Luck, Michel

Hi Michel,

Thanks for the answer. As I said, I only understand a little German, so I missed the part that showed that one must view the curvature plot prior to converting to chines. Also, the strange plot I was seeing seems to be a quirk of the program. I had collapsed one point as I attempted to develop the cutaway part of the deck on which the beam structure would rest. When I selected the option to show the interior lines, I saw an odd fold.

Changing the language to German is a good idea! I did not think of that.

There is an article right here on these forums about using Freeship to do a proa. I found it by googling “freeship proa.” It’s the top hit. Here’s the link. There is even a file to download. Neat boat! I like Walaps.

As the author indicates, the method used hoses your hydrostatics, but given that the hulls could be developed in separate files, then his method could be used to mock up the connected forms.

As to starting with a dory? I probably should have done that, but I fear that it is too late for that. I am, however, working my way through the manual, inch by inch.

Were you to produce an English tutorial, even if not proa specific, it would be a great contribution. Freeship certainly is great program. Being able to check one’s hydrostatics incrementally is just fantastic. The way I learned, way back, involves breaking all the forms down into triangular cross section extrusions and working one’s way down the hull. It works. My primitive calculations were within 2.0%-4.0% of Freeship’s calculations, but the method is very tedious and error prone due to the difficulty of accurately measuring small scale drawings with a ruler or compass.

Also, I understand that Delftship is simply a proprietary extension of the program. Have you used it? (I’m rather fond of GPL programs though.)

Best,
Rick

Hi Rick,
yes I tried Delft free version but some important functions are not available, so I went to freeship which is so complete that you can use it up to building stage. Ok, iam in the learning progress and have massive difficulties putting details onto the hull, but in designing the bare hulls iam quite good. *smile*

I learned boat design the old way and in the moment I am mixing the old way (on paper and calculator) with working out fair hulls with cad.

Freeship and Delftship started as one programm from the one programmers team (students at nautical design school in Delft/Netherlands) that separated later on. Thats why they look so similar. Delft is more orientated to be professional and earning money.

Starting with a dory hull ... is not too late. With your design you will come to a point where you have to crash your design into the bucket, because nothing will move anymore due to some errors (normally too much points that block each other). Then you have to start new and rebuild it. To get practise its no problem to have several designs stored at freeships folder to work with one at a time. When you get a little routine at the simple model everything will become more logical and will work on the real model as well.

I will not write a a complete tutural for freeship, but I will show some important steps and points that will make it easyier to design fore and aft symetrical proa hulls. There is a tutural in freeship included (see “Help”) and the small german tutural from the link shows the major steps you have just to repeate to get a fair hull. Everything further would mean that I write a book about “how to design a small boat”. *smile*.

If you have problems to draw fair hulls and you cannot solve them, tell me and I design the hulls for, so that you can build them.

Regards, Michel

Tips and Tricks Part 1 .... General

1. Pre-Design considerations and calculations.

Many people believe that their “dreamboat” is easily designed with a cad program, because they see it in their mind. Unfotunally this is not true.

Boat Design is not fairing lines into a hull that looks sexy. Boat design is bringing Volume (needed to carry a specific weight in water) in into a hydrdynamical effective form…. that is looking sexy too

Boat design is done in designspirals doing the same process a few times. With every round in the spiral your estimations will be more and more precise to end up with (quite) secured numbers. So it all starts with wheight and volume. (And the length of the boat that you will know anyyway) To get this impotant starting number you have to know or estimate what the boat will wheigh at launching day and what payload (Crewwheight and gear) you will add on it.

Estimate the wheight of the hulls surface, the bulkheads and stringers, all the interior panels, the cockpit, the ama, the rig and the crossbeams. So far for the structure, go on with the crew and their personal gear (est. 100 - 120 kg per person), the stores, the motor, water, fuel, anchor and ropes, elektrical systems and all you want to have on board. Count it all together and you get your most important number for design:  the Displacement. In a Proa, the Vaka must be able to carry all this wheight alone at a stable trim and high speed. There is no much room for tolerances because the ama is flying then and the reserve for stability is low.

Plywood surfaces for example: Okume Marine Plywood covered with epoxy (2 layers each side) and one outside layer of 5 or 6 oz. glass, finished with filler and paint (or gloss) will wheigh: 6mm =  4.0 - 4.3 kg / m² .... 4mm = 3.0 - 3.3 kg/m².

2. General arangement

Before you go into freeship its a good thing to know how much bulkheads you will have and where they are located, The beam of the hull at deck and in waterline, length of the cockpit between the beams, the freeboard at the bows and the inside height. Make a rough sketch, but at the right scale, on paper and try to arrange every impotant part of the boat onto it. (see the handmade sketch at the “flying apple crate” thread as an example.

Now its time to open freeship ... go on with part two

Michel

Tips and Tricks ... Part two:

First steps at freeship.

Proa hulls normally are symetrical fore and aft. To achieve this in freeship there are a few tricks.

1. When you open a new model, freeship asks for the numbers of points longitudial and vertical.

Long = choose a uneven number of points and as few as possible ... its far easier to fair the lines. For a small proa up to 7 or 8 metres I choose 7 points (bow, intermediate, beam, middle, beam, intermediate, bow)

Vertical= choose one point more than the number of panels per side you want to have… just for the hull, not more ... you can add the deck later on.

length, beam, draft: choose as you wish.

2. When freeship opens the lines

- Edit (with the small window that opens when you mark a point) or pull the points longitudually into the right positions:  middle, mainstrength (beam) bulkeads, intermediate bulkheads, bows.

Put all points of one section in a vertical line too, this avoids to get hollow lines. Think of them as if you were drawing the real bulkheads. The same distances from the middle (or the bows) will make the hull symetrical fore and aft. (its good to have the positions from the paper sketch now.

- Reduce the numbers of sections and waterlines given by freeship to make the picture not so overloded with lines.
Path: “Calkulations” -> “Intersections” ->
-> sections: choose bucket (delete all stations) -> +N (add multiple stations) -> distance between stations 0.5 or 0.6m or as you wish ..
-> waterlines: the same but distance 0.2m ... perhaps choose +1 to add single waterlines at 0.1 and 0.3
(underwater) or as you want them to have.

When you finished your hull design it could be useful to use this feature to show the form of your main bulkheads. Simply put another bulkhead with “+1” into the right position. Or delete all regular stations and just put the real ones into their position

- Now you can pull or edit the points to bring the hull into the desired shape. To make a chine:  mark the longitudual (grey) lines that connect the points and press the button “knuckle lines” as shown in the german tutural.

- Check the hydrostatics regularly to achieve the needed volume with your lines. “Calculations” -> “Design Hydrostatics”. Here you find all your needed measures and data you are producing when you “shape” the hull.

- Draft: other than length and beam you cannot change the draft in the linesplan. To do so (if you want to increase draft to have more volume underwater) go to: “Project” -> “Project Settings” -> “Main Dimensions” -> you can edit the draft, correcting the numbers and enter with “green hook”. This feature is also good to check the overall volume of your ama. Increase draft all up to the sheer line and check the hydrostatics.

- For a perfekt fore and aft symmetry all points must have the same data as their “partnerpoints” on the other side of the boat. Edit them in the small window.

- Do the design step by step Make the hull first until you are satisfied with it, then lock all points, save your work and close freeship. Open your freeship folder, copy and paste your design and and continue with the copy, having your perfect hull save as a backup. sometimes you will work errors into your design that blocks the points, then you have to throw it away and start again.

- Scaling: If you have worked out a perfect hull and want to try some kind of variation-  for example your ama is too big and you want a smaller and lighter one, use the scale function. Press “Transform” -> “Scale” -> and choose a vektor/multiplicator in all 3 axis (for example 0.9 for a 10% smaller hull). Or make the hull longer, fatter or as you wish with scaling just one axis. Important: do not have a point or a line marked when you activate the scale function. after activation all points are marked automatically.

- When you went into a process that has lead into an error, you can reverse every single step with “Edit” -> “undo .....” or “repeat” them when you reversed on step to far.

So far for now ... good luck, Michel

Michel, A great series you have begun!

I stayed too late last night and then woke up too early, for I became obsessed with implementing a proa with Freeship. Rather than follow the method used in the aforementioned link to an old article, I exported the ama as a .part file, and then imported it into the main file. I did the same with the aka structure.

That method does work; however, you will get some weird results. You have to mirror the sides of the hulls longitudinally, and this will ruin your hydrostatics, for Freeship will think you have a wider hull, so the technique is purely for rendering, but it can be done.

Finally, I concluded that Freeship is not really designed for the intricate tying together of too many disparate parts. One would do well to use a CAD program for that. Also, Freeship’s rendering engine is crude, so for pretty pictures, one would need a more specialized program. I was getting quite irritated trying to do things that were easy in Blender, for example.

(Listen to me, I’ve hardly used the program, but here I am criticizing a cat because he’s not an elephant, sorry. Fact is, Freeship IS the anchor in my current workflow, no doubt.)

Still… See attached. (I’m not too happy with it, but I thought it was time I put something up, you know?)

Also, thanks Michel for the detailed advice. At this moment, I only scanned it quickly. After all my frustrations with this, I fully intend to start all over from the beginning, step by step, using simple forms. (And using your advice.)

Best,
Rick

It is evening now. And back from my final. final at school, I am done for the semester and can once again concentrate. This time I’m following your advice, Michel. After reading over the above, and after doing a whole lot of wrong-headed shenanigans, I’m using your orderly method. (Wie sagt man “shenanigans” auf Deutsch?)

For my test project, I’m designing a paddling proa. I have in mind skin on frame! Check out the lovely boats on Geodesic Airolite Boats for a sense of the grace of these kinds of craft.

I shall pose my efforts here for a critique.

Cheers,
Rick

[Edit: PS, I’m using metric for this design. I need the practice. I always use tenths of feet and inches anyway, why not bite the bullets and go all the way? 😊 ]

Well, I started drafting at about 10:45 PM and finished about 12:45AM. I also watched the end of a movie and had dinner, but here is the vaka of a paddling proa.

Design objectives: The absolute minimum one man paddling proa. Displacement ~275#. Thats me at 190 with a bunch of gear lashed to the hull, so upwards of 230# Pretty damn sure I can bring the boat in at absolutely no more than 50#. Probably less. I wanted the longest, lowest hull form I could get. The shape is based on my experiences paddling in the open sea and the surf of the South Pacific. This is a wet boat. It is not suitable for cold weather. I did not attach a rudder. After paddling a bunch of these things with rudders, I finally figured out that they were good at slowing you down, but nothing else. (YMMV) Also, I have not carved out the seat area. I am leaving that as a future exercise. One may note a sort of “nose down” attitude to this craft. That is intentional. You lean back when you catch a wave, getting the flat aft lines to surf, and this keeps the nose from plowing in. But in normal running, the tail sits up above the water. In actual practice, the water flows nicely aft, but when the back goes under, you can really feel the drag. The rakish rake is purely for style. You don’t really need that, but one gets that traditional look.

Point is, I followed the above advice and knocked out a nice, clean, orderly hull in rapid fashion.

Here are the stats:

Length over all     :    6.599 [m]
Beam over all       :    0.424 [m]
Design draft       :    0.125 [m]

And here are some pix:

Cheers,
Rick

Oh yeah, he’s called “Whisp.”

Hi Rick,

you have drawn a wonderful hull. I have no experience how this kind of should look like but you have done well.

Having a skin of frame, would it be better if you use a multichine section? I love this skin ob frame boats and I hope I will build one some day. I have a book here that discribes how to build a original greenland inuit kayak, but unfortunally I would have to kill 6 or 7 seals to build the skin (just a joke).

With freeship you hit the point. It`‘s not made for renderings, its made for design, fair lines and correct data. I dont even know how to incororate the ama and akas for example. This is one of the points I have to learn. Your computer knowledge seems to be far superior to mine. Can you import freeship hulls into other rendering programms and “mount” them together there?

Iam a boatbuilder and a amateur designer, if I see a set of linesplans the hull pictures in my “inner eye”. It will become critical as soon as I want to show my results to someone other. Everybody is so much used to see computer animations today that nearly nobody (exept boatbuilders and designers) can “read” a linesplan anymore.

I dont know the word shenanigan and the translater says “schwindel” but this does not hit exact the meaning of your sentence. But I understood what you mean.

Never heard of someone using tenth of an foot or inch. When I built the first CLC “Northbay” Kayak I had to decide wether to use the foot, inch and 1/8th’s or translate everything into metric. I have chosen the foots and get used to it after a little time and errors. But my thinking is in metric and will stay there. freeship can do foot and inches as well.

regards, Michel

Hi Michel,

Thanks for your kind words with regard to my computer skills, but I think you overestimate them. I have used computers for art probably more than most people, and maybe some of that transfers over to this skill. It is as you say, one must have an “eye.”

Looking over this hull, I see I could have used an extra set of points along near the keel. The aft part should flatten out a bit more, and I think the bow could be a tiny touch fuller, a tiny bit more forward.

With regard to skin on frame, my thinking was exactly yours: a chine hull. But looking at the boats in the aforementioned link to Geodesic Boats, I saw that many, many chines would result in a safer, stronger AND lighter hull. To get the effect in Freeship, I would need something like twenty control points at each station!

One point of advice you made clear is that one must really strive to keep the number of control points to the minimum, and my limited experience bears this out.

This design is for heat shrinkable dacron skin. Using a heavy, rubberized laminated skin, as is used on a Klepper Faltboot that is designed to be disassembled and folded, would demand fewer chines. OTOH, the Aleut types seem to use more chines with highly rounded forms.

So I decided that since I was going with so many chines, the thing to do was to figure out the precise locations of the stringers at the building stage and just use Freeship to get a fair hull shape. The skin is laid on in one piece anyway. In this method, one does not cut panels as in plywood, so Freeship’s amazing feature for loft panels was no use in this case.

BTW, I found a very good link to this construction technique which follows the dacron skin with epoxy and polyester. You can read about it in this article at Duckworks.

And “shenanigans” is an old fashioned word. It’s something my grandfather would say in reference to kids playing around mischievously. It implies some sort of immorality, actually, but for old fashioned Americans like my grandfather, “playing around” is suspicious. One should be result oriented and disciplined. My first attempts at using Freeship resulted in crazy messes, so I was “playing around mischievously” when I used the word. I can see why your translator might use “schwindel.” It could mean that, but there is a softer, more humorous sense in general usage.

Using decimal inches is something I started doing in high school. My drafting teacher gave me an “engineer’s scale” when he saw me coming in after school to work on my boat designs—not part of our school assignments. I was struggling with the calculations, converting eights and sixteenths and twelfths to decimal to calculate, then converting them back, so he suggested I just do what engineers do and gifted me with that scale. I still have it, all beat up from crashing around in my tool box for years. They sell them at drafting supply places. They are sort of prism shaped, with six different scales, just like the metric scales. Very handy.

Still, I am trying to get a feel for metric sizes. I like the way the numbers are so compact and tidy. This semester, I had a science teacher, a German, who tried to persuade us to get a feel for metric in common use. One point he made was that metric was not based on the dimensions of some king’s body, so it was an egalitarian set of units. I like that.

Even so, translating is a pain, as you discovered. One should just use the system used in the plans. (I have never seen plans which used decimal inches. I doubt many builders even have such scales. Aircraft are another matter, however.)

Now then, time to put on my overalls and cut some wood.

Best,
Rick

Rick - 16 December 2011 09:32 AM

Looking over this hull, I see I could have used an extra set of points along near the keel. The aft part should flatten out a bit more, and I think the bow could be a tiny touch fuller, a tiny bit more forward.

Don’t expect a design to be ready after one day or two. With a few days in between you always will find points or areas that could be done better.

You can have another controlpoint or a set of controlpoints.
mark a section of a controlline and press “create a new controlpoint by splitting a controledge into two”

Thats a good time to work with a copy instead of the original. You can compare the two after doing the modification.

Best Regards, Michel

I appreciate all the good advice, Michel.

This past week, I’ve been staying up late practicing. I’ve gone through several variations on several designs. Finally, I came up with a 6.4m/21ft design that would be a good test platform for rig designs. It’s not exactly a one-man test vehicle, but for a boat of that length, it’s very light—yet still workable. I have too many relatives and friends, so a purely one man boat just won’t work. This guy is planned to displace 272kg/600lbs, fully loaded, so it’s an ultra-light, but it could haul a bit of crew weight.

I’ll start another thread with the design details, but here’s a neat picture. I ended up using Delftship. Freeship has bugs that irritated me to distraction; that is, it would lose track of mouse-wheel focus, so I could suddenly not zoom in and out with the wheel, and keyboard commands would come and go. Also Delftship allows one to drag a rectangle around the area one wishes to zoom, so it is simply much faster to use. As to any missing features, I cannot find them! Note also the “environmental” mode which gives a mirror finish to the rendering. Pretty cool…

Rick

PS I’ll be upgrading to the pro version. Martijn van Engeland has done a superb job, and I’d like to support his work with cash. (Also, the pro version supports asymmetrical design)