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  #31  
Old 12-02-2005, 07:45 PM
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PAR PAR is offline
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This was my point in the first place with the cracks about free design software.

Lets see, you down load, say FreeShip and plug in the dimensions you want. Ta Da, you have it! A boat, wow. You know how much it will displace (at least at the default 12" setting) some interesting numbers to show your friends, but now what?

What is the planking thicknesses? What are the sidings and molded dimensions of the keel, floors, frames, gussets, deck beam, etc. What centers are these pieces placed on? Attachment types, joints, fastener specifications, etc., etc., etc. The list is quite long.

You really don't have a boat designed do you, just a pretty picture of a boat shape that very likely will not float as it's shown on the screen.

I think anyone that wants to do a design, should first do a center of longitudinal and athwart masses calculation. If this doesn't teach them, then maybe panel loading and rig fitting dimensioning for one of LFH's big ketches, say "Bounty" and see if they've had enough.

The drawing on the screen looks prettier and prettier all the time, but that's all it is.

I finished the drawings to a custom aluminum sailboat last month. Calculations were done previously and the design brief has consumed all of this month. I'm still not done, I've yet to do the details on the centerboard, rudder, motor well and a few other things. I'm not drawing anything, just noting specifications, anode locations, marking what size heli-coil to use on which bolt, etc. Very glamorous stuff.

This is the false impression I think the free and low cost software generates. It doesn't help anything really, because the job it performs doesn't account for much in the total picture of a plans package.
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  #32  
Old 12-02-2005, 08:55 PM
cyclops cyclops is offline
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Computer programs are like medicens. All help, few cure. You still have not got to where you want to be.
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  #33  
Old 12-02-2005, 09:06 PM
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RHough RHough is offline
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Quote:
Originally Posted by PAR
This was my point in the first place with the cracks about free design software.
<snip>
Just for the sake of argument.

I download Freeship and make a pretty drawing.

My boat is 24 ft long.

I look at plans for 24ft boats and note their construction, hull thickness, frame spacing etc.

I use those because math R hard.

I look at engine sizes or rigging sizes and copy those too.

I build me a boat.

Want to bet that it will float?

It is no different than going to Home Depot buying some lumber and nails remodeling your house. People do it all the time. I'm sure it drives Architects and Engineers crazy.

The very nature of boats means that almost all of them are overbuilt. A designer cannot take the chance that no one will drill a hole in a bulkhead to install a water cannon or whatever, the bulkhead is overbuilt so the design won't fail if someone does. Rigs don't fall down for a 1/32" change in wire size.

There is NO Doubt that the boat will be far from what it could be, but freeship and a tiny bit of common sense will make it work. Maybe not well, but it will float.

There will always be people that don't get it. They don't know what does into a custom design. They don't know quality of design or construction. They shop at IKEA and WalMart. They get what they pay for.
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  #34  
Old 12-02-2005, 09:31 PM
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PAR PAR is offline
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Sure it may float, but not where the pretty drawing says it will. All the numbers generated by the software are based on it floating as drawn. It may be bow down, stern down, listing to one side, etc.

The other thing is matching displacement. In order to build the boat, even if using another boat's scantlings, it has to have an underwater volume that matches it masses calculations. In other words, If the other boat had 1/2" planking, 1 x 3 frames on 18" centers, equipped as such, etc. and the same was done on your boat, you still don't know where she'll float or how she'll float. It easier to know the tanks must be moved aft to keep the bow trimmed on her LWL then to have to cut them out and figure something out on launch day. What happens if she's heavy and floating low? What do you toss ashore or do you just repaint the waterline 3" higher then it's supposed to be. What happens if it's a planning craft and is built too heavy and can't plane or a sailboat that's to lightly constructed to stand up to the rig.

Yes, a small skiff can be built by patterning it after similar skiffs, you really don't need software for that. Unfortunately, I'm seeing people trying to design retirement yachts to cruise the world in as well as a fishing skiff. This is the part that bugs me. People make changes, that's great, but they don't understand the ramifications that some of the changes they make may have. Additional ballast to hold her upright, but the rig keeps falling down from the unforeseen increased loading. Hell, I don't care if someone makes a dayboat and has fun with it. I just don't want to see an avalanche, like the one we had in the 60's and early 70's producing children only a mother could love. This new software thing may just do it and the dark years of the 70's and 80's will be back. For those of use that lived through both periods, I'm sure no one wants to go back. Yachts got such a bad rep, you couldn't sell one if it was dipped in gold.
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  #35  
Old 12-03-2005, 12:41 AM
tspeer tspeer is offline
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I think a big reason for the difference between open-systems programming and boat building is computer programs are cheap to produce and the major effort is the non-recurring cost of designing the software. So by everyone chipping in on the design, everyone gets a copy of the result.

For boat building, the recurring cost of production far outweighs the non-recurring cost of design. So the better open-source analog is several people building a single boat and then sailing it together. That way they each enjoy the benefits of the other team members' labor and investment.

As an amateur, I find the main benefit of working on my own design is to get a better understanding of the requirements and their impact on the design. When I can afford to build, I'll use that experience when I go to a NA to work up the actual design. I'll be much smarter about what the performance constraints are and I'll be able to say, "Here's something along the lines of what I want," so we have a concrete starting point.
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  #36  
Old 12-03-2005, 01:14 AM
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Caldera Boats Caldera Boats is offline
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This thread is really getting good..

If you build it stronger than you think it needs to be, the safer it will be.....
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  #37  
Old 12-03-2005, 01:40 AM
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A question for the designers.

I'm going to build a Bolger Light Schooner, sort of.

Before I cut the first part, I'm looking at every little detail and looking at ways to change the bits I don't like. My priorities are different than those of the original customer that commissioned the design. But much of the boat is a perfect fit.

What changes would make the finished boat my design, inspired by Mr Bolger's?

What features and dimensions can the two boats share? What features and dimensions must be different to make it my design?

I'm changing the sail plan.
I'm changing the spar dimensions and sections.
I'm changing the daggerboard position and section.
I'm changing the rudder profile and section.
I'm adding ballast.
I may end up changing the lines forward to add reserve buoyancy (the Bolger Design submarines when driven hard downwind).

Is it now my boat?
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  #38  
Old 12-03-2005, 02:14 AM
nero nero is offline
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"If you build it stronger than you think it needs to be, the safer it will be....." Not necessarily true. If the extra weight of a stronger piece(s) creates more stress on other parts of the boat. It is all about balance ... in many dimensions.

I suppose I am one of those that raises PAR's blood pressure. Yes, I was born in '65 ... but not in CA. smile. I guess what saved me, is my rural country background and building with my father since age 6. Even more dangerous, unloveable kids are still being produced!

Don't know about others programs. Drawing a displacement hull in TouchCad and getting it to float on line was straight forward. Scantlings take care of the structural questions (for mono hulls). Zen helps deal with the design/engineering spiral. Ofcourse, nothing is certain till the boat floats ... and sails thru it's first storm. This adds some adventure to this long, design/build process.

Perhaps that amature builder/designers have different goals than NA's. For me it is about realizing a 28 year old dream, the experiences, art, challenges, and thrills. My wife says it is what I live for.

Beside's income, what are the motivations for NA's?
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  #39  
Old 12-03-2005, 03:11 AM
tamkvaitis tamkvaitis is offline
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Is there any valounteers who would like to start drawing and designing? I have designed(I am not a professional and I know that my drawings are full of mistakes and thiongs like that) an 8 meter sailing boat. I have used cad drawings because you have much more freedom of creativity then using this kind of program (autocad etc.). All calculations that I have made is based on books that I have. Basicly it is russian literature. All the structural things like bulkhead, skin thicknes, stringer placement I have done intuitivly. Is it a boat?
Yes
I am sure that it would float, but I am not sure about its performance and seavorthines. This is the main thing that is beetwen the professional designer and an amateur like me. Things like performance and seaworthines are quite dificult to predict by an amateur.
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  #40  
Old 12-03-2005, 03:17 AM
tamkvaitis tamkvaitis is offline
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I think we could create four groups
1. Is cruising boats which lenghts is under 10 m.
2 Is cruising boats which lenghts betveen 10-15 m.
3. Is cruising boats over 15 m.
4. Is performance boats which haven't got any limitations.

structural design (or sketches of it) must be done
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  #41  
Old 12-03-2005, 03:35 AM
Robjl Robjl is offline
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Talent not skill..

So many different views ... I've got to add my two bobs worth.
It must really **** some that the laborious tasks associated with hull design are now done with a few touches on a mouse button and the unfathomable elements of design are gone. No-one needs to use "Simpsons rule" again.
Surely nothing is wrong with that?
Well there is....
The software only goes part way, it doesn't do the whole job as some have pointed out, example: the software works out LCB which many mistake for LCG!, some think they are the same thing.
The software doesn't do scantlings and a whole lot more.
But what really stands out is the lack of talent not skill in most designs.
The truly great designers have an eye for the ship's form.
I don't know if they learned it over many years or it is just innate talent like an artist!
And above all else, the yacht should be a thing of grace and a joy to behold.
Otherwise why would you bother...
What I am really trying to say is the only thing wrong with amateurs trying to design and build boats is that many of the designs I have seen are dog ugly. This sounds opinionated and rude and I am reluctant to even say it but I will as I really believe that it takes a practised and trained eye to see the difference between a rendered model and a finished boat.
And it takes experience, experience mucking about with boats, experience at boat building, experience developing hand skills and a knowledge of materials, and of course study so the important essentials of strength and suitability for purpose are met.
Is the discussion worthwhile.. absolutely, but amateurs should be under no illusion that their early attempts are anything but a stepping stone in the learning process. As a minimum they should complete one complete design before starting on a boat they want to build. If you can't complete a full set of drawings and specs to build the boat... so that some-else could build the boat.. you shouldn't start.
And finally the group project.
A group may formulate a very detailed "design brief", maybe with some rendered sketches to illustrate ideas. Then accept individual proposals. But a complete design by a group.. not likely.

Remember the camel..that was horse designed by a committee.

Cheers all.
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  #42  
Old 12-03-2005, 07:32 AM
yokebutt yokebutt is offline
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Boat design is already open-source in a sense, since you really can't hide anything actually implemented in a boat. But, good boat design is really a matter of blending and balancing a large number of factors rather than coming up with a single "magic bullet", so without a thorough understanding of every aspect involved, a new design is unlikely to make a good boat.

Yoke.
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  #43  
Old 12-03-2005, 08:44 AM
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Guillermo Guillermo is offline
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Quote:
Originally Posted by Robjl
...........................................
The truly great designers have an eye for the ship's form.
...........................................
And it takes experience, experience mucking about with boats, experience at boat building, experience developing hand skills and a knowledge of materials, and of course study so the important essentials of strength and suitability for purpose are met.
............................................
A group may formulate a very detailed "design brief", maybe with some rendered sketches to illustrate ideas. Then accept individual proposals. But a complete design by a group.. not likely.

Remember the camel..that was horse designed by a committee.

Cheers all.

I couldn't agree more. A good designer needs both Talent and Skills. On the side of the designing group idea, I firmly believe no group may succeed except if working under a strong and knowledgeable leadership
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  #44  
Old 12-03-2005, 12:19 PM
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JonathanCole JonathanCole is offline
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The Big Picture

This is a very interesting thread and the many accurate and useful perspectives among the contributors shows some interesting facts. There are 6 billion people on the planet and each one has their own unique story, which to them, according to their experience makes absolute sense. No one can really prove that one persons story is any better than any other persons story, but by comparing our stories we have the chance to influence the opinions of others and develop a more useful and workable ongoing story.

BoatDesign.net is like opensource programming in a way. Maybe more like open source education. It is challenging, interesting, enlightening, sometimes infuriating, but definitely the wave of the future in education. I think the reason that BoatDesign is leading the way here, is that if you can figure out a productive way for people who are as individualistic as boat people, to communicate and expand the population of the educated, you have really accomplished something. My hat's off to all the good people willing to expose themselves to criticism by communicating their views for the benefit of the group. Long live BoatDesign.net!
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  #45  
Old 12-03-2005, 07:05 PM
Robjl Robjl is offline
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Why there aren't anything like that????

Sometimes it pays to go back to the "Design Brief", in this case the original question:
"I am sailing for 17 years. I have decided to create and build a sailboat. I found a lot of projects articles and drawings in the internet. But I havent found anything like free designs, drawings etc.. Why there aren't anything like that?"
The answer to this question is obvious from my perspective...
There are plenty of Freebies on the net. Sure these plans lack some detail but with a little research that shouldn't be the problem. At the back of my mind is always the question.."If the design is any good why would it be free"???
Sorry folks..but I just don't see a competant designer giving away months of work for free. But an amateur who wants to see his project built...yes.
Would I be prepared to take the chance...never.
I did the research myself until I was sure my project will work..then I got it checked to see that it complied with the relevant standards.
Yes I did it my way. (apologies to Frank)
But this will be the third cruising yacht I have built, I know I've got the Skills and Knowledge to succeed, also the money and the perserverance.
I have concerns that this "educational forum" makes it all sound so commonplace and easy for those with no experience in the trade.

"BoatDesign.net is like opensource programming in a way. Maybe more like open source education." .....yes I agree wholeheartedly with Jonathan and support it.

But I can't completely agree with Guillermo,
"On the side of the designing group idea, I firmly believe no group may succeed except if working under a strong and knowledging leadership."

Strong and knowledgable leadership will produce what the leadership wants, I can't see too many others contributing.

But why would we want to design a group boat anyway??

Because someone wants a free design with specs and construction guide??

Doesn't this forum already provide help and advice when it is asked for on a question by question basis...and with pretty quick responses?

Tamkvaitis, you wouldn't let us guys choose a wife for you even if you had confidence in our collective wisdom. Go buy a set of plans or do your own and ask questions when you get stuck.
Good Luck.
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