Replies to This Discussion

Permalink Reply by Rick Newman on August 7, 2012 at 1:57pm

Michael, the folks on the WoodenBpat Forum mention Delftship, www.delftship.net for their design work. Google Sketchup is also popular but isn't a marine CAD program like Delftship. There is another program they use but I can't remember the name of it. Old age does that to you.

Guy Fredrickson's early posts mentioned his development techniques. He even used an Excel program that he worked up. It was suggested that he build a model and if I remember correctly he mentioned something like "I'm glad I built a model it helped me envision the boat better" and he made changes based on the model.

Roger discusses model building and development of hull shapes in his book. Sandy Pittenrigh also discusses hull design on his site, as well as how to make a "flat spot" by dishing the bottom of the side panel.

In Roger's book he mentions Dynamite Payson. Dynamite was a good friend of his and help Roger develop the Dave Z hull design discussed in his book. Mr Payson wrote numerous books on building "Instant Boats", his name for stitch and glue. Dynamite has done a good job of describing the techniques of developing hull shapes and simple methods for model building to confirm your designs match your expectations.

I have never lofted a boat but think I could struggle through it. You could transfer your coordinate values to paper and loft your design from that.

Keep us informed.

Rick "Mahog" Newman

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Permalink Reply by Michael Rosso on August 7, 2012 at 5:37pm

Rick,

I was trying to find those discussions where the Excel programming was mentioned but like I said, I couldn't remember what they were about exactly.

I'm going to see about getting some of Roger's books.  they sound like an awesome read!

Take care, buddy

M

 

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Permalink Reply by Guy Fredrickson on August 7, 2012 at 4:51pm

Mike, You are dealing with the same problem that I faced when I started my project.  A curved surface that can be rendered onto a flat surface is said to be a "developable" curved surface.  Obviously, not all curved surfaces are developable.  In fact, it is a very special property of a curved surface for it to be developable.

I approached the problem from reverse.  Rather than starting with a 3D rendering of a hull and hoping that it was a developable surface, I started by defining my side panels as flat surfaces (with four straight edges) and then bent them into curved surfaces.  That way I KNEW that the resulting curved surfaces would be "developable".

Does that make sense?  I tried to explain a lot of this in my early posts.  I think this appraoch is a good approach to take even if you use something like AutoCAD or TurboCAD.  But if developing 3D surfaces is what you want to do, then make sure that CAD program supports that function.  (If I recall properly, TurboCAD does not have that function.)  I hope that helps.  Let me know if you have any questions.  Guy

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Permalink Reply by Guy Fredrickson on August 7, 2012 at 4:59pm

I played around with this program.

http://www.pilot3d.com/

It has the ability to develop 3D surfaces.

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Permalink Reply by Michael Rosso on August 7, 2012 at 5:21pm

Thanks, Guy!

Just checked it out and it seems to be just what I'm looking for.  The price is reasonable, too.  Who'd of thunk?

This is going to save me a heap of time.  When my wife finds out I'm planning another boat she's gonna kill me.

Take care, thanks again.

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Permalink Reply by Guy Fredrickson on August 7, 2012 at 5:46pm

And also, the three most important things to do once you have your design and dimensions are 1) build a scale model, 2) build a scale model, and 3) build a scale model.

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Permalink Reply by Michael Rosso on August 7, 2012 at 6:27pm

In that exact order?  Or can I start with #2 first?

:)

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Permalink Reply by Guy Fredrickson on August 7, 2012 at 6:49pm

For me is was 1) built a paper model that failed and allowed me to catch my calculation error in the spreadsheet, 2) built a second paper model that was successful and confirmed that I got my basic dimensions right, and 3) built a wooden model that taught me what dimensions are most useful for a cut sheet intended for a compound miter saw and a table saw. It really was a valuable learning process.

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Permalink Reply by Randy Dersham on August 8, 2012 at 2:17pm

The industry standard for marine design is Rhino.  It's expensive. ($995.00) http://www.rhino3d.com/

It has one drawback which is that it does not like to allow you to move one point while keeping a fair line with the other points.  I believe the best program for that is ProChine. http://www.newavesys.com/products.htm ProChine is only $95.00 and is great for creating hull shapes only.

Both programs allow you to develop a surface which is a critical feature.

My workflow is to start with a Prochine half model to get the shape and dimensions I am after for the hull. Then transfer the ProChine file into RhinoCam where I build out and fit all of the other parts into the boat.  Finally the parts are separated and developed in either 2D or 3D depending on the shape of the part and finally a cut file is made for the CnC. 

This actually the same process used in freeform boat building except in traditional freeform the first boat is built actual size and then it can be taken apart and used for patterns. Of course you can do the same thing by developing a scale model then take it apart and loft the developed pieces to actual size.  

The key to free form is to use the developed side panels as the guide to attach all other parts. The same process can be used for stitch and glue building but the frames are temporary and are removed during the build as other structural permanent parts are added. 

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Permalink Reply by Michael Rosso on August 9, 2012 at 8:07am

That was great info, Randy.  Thanks a lot.   I know a lot of those design programs are supported by sketchup.  I wonder if I can import the hull design and do the buildout with it.   I only say this since I'm already so familiar with it.  I'll have to check on that.

I'll take a look at newavesys.com.   Sounds really interesting.

Thanks again!

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Permalink Reply by Duane Doran on September 17, 2012 at 9:57am

We choose not to use any program specific to an industry or product as we find there are always limitations. I see several that Randy mentions with Rhino. Using true parametric solid object software will allow you to create virtually anything. You can create lofts, extrusions, sweeps, and revolves in both boss and cut. The ability to create in real time and the various tools that let you check the surface area of a part or assembly, create cross section views, exploded views, etc. are invaluable. For example these tools let you calculate displacement in a few seconds.

We use a product by Alibre Design and it while it's a bit more expensive than Rhino and has a bit of a learning curve we find it's well worth it. The program also has a built in parts library with millions of predrawn nuts, bolts, bearings, washers, etc. and access to an online catalog of hatches, hinges, doors, etc. that are easy to download and incorporate in your project.

We have done several boats so far and are blown away with what can be done. Another benefit is the ability to create your model then send the file to a 3D printing company and for little money you can have a plastic scale model of your boat for hydraulic testing. We have one rather unique new boat design and we created a 3D printed model of it and one of a typical drift boat. The engineering department at one of Oregon's major Universities then prepared a series hydraulic tests for us to create a real time comparison for healing, free drift speed, standing wave pressure, etc.

Anyway, these tools are expensive and take time to master but you will be amazed at what can be done. Is it worth it for a single boat? Only you can answer that question.

 

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Permalink Reply by Michael Rosso on September 17, 2012 at 11:23am

Thanks, Duane.

That sounds fantastic.   It's amazing to know how much is out there.  Especially after having originally thought I had really 'looked' and found nothing of real interest.   I should have posted here FIRST.   as always..  :)

I had been devoted to my driftboat project most of this past spring and have only recently started tackling my 'honey-do' list.  I'll probably dive into all of this design work when the snow starts a-blowin' outside.

Thanks again!

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