making a scale cardboard model

Very wise words and thanks for the tutorial.

It's not a history of passion, it's a philosophical problem: the old one of praxis and logos. Or if you prefer utility. Whats means to use to get a satisfactory result.

Example One: Mr X want to make a small boat style lobster 20 feet. Ok does he need to learn Free Ship, and design a boat? No, better to buy plans. It's easy to change a layout when you have the hull plans.

Example Two; Mr Y has no knowledge but thinks that he can design a boat better than a professional. Even the 100 USD for plans are too expensive. A very common situation. No need to say that whatever the soft he will use, the probability that the result is awful is 99.9999 %. No need to use a big soft like Free Ship, a simple one will be enough.

Example Three: Mr Z likes boat design thus has a good knowledge, and love small fishing boats. He builds one every 3 years...Does he need a soft like Free Ship with all the bells and whistles? No truly for such simple boats, a simple soft is largely enough for the purpose. Free Ship optional, if he has plenty free time, and wants extra results.

Example Four; Mr W has 20 years of navigation, his nautical books weight at least 3 tons, he is engineer and he wants badly HIS boat, a 14 meters motor cruiser. By HIS I mean thought, designed and built by himself and nobody other. HIS MASTER PIECE. Does he need a Free Ship? Yes!!! Add some other softs and 53 spread sheets. The same answer for an addict of boat design, he needs the best tools.

I do not talk about a pro, he uses tools for pros and pays the price, because he wants precision, productivity ans a responsible in the event of problems. I had this tools for complex works, like anyone working in the field. A remark: for designing boats splines and better Tsplines are more efficient than NURBS.

I do not despise computers, I have used computers since more than 30 years as a tool, nothing more. I have tweaked many OS, used and modified many softs and spent too many hours programming when the programs had to be made because there was nothing in the market. But I'm not a geek...I prefer to be in bed with my wife and have some physical activities with her.

And being pragmatic, I do not see the utility of a big tool for a small work and I go for the simpler and faster. And sometimes is better to get out of the virtual and see the reality, ie a model can tell a lot of things. A sheet of paper, a pencil also as you have to think...

Last question; how many hours of learning do you need to master at least 80% of the possibilities of Free Ship? Never been bothered by some problems?. (I have a Free Ship and I know to use it, as I have plenty of CAD softs from the crudest to the more refined, plus some jewels not found every day.)

Is it worth to spend all these hours for just ONE LOBSTER 20 FEET HARD CHINE BOAT?

 

The problem with NURBS...I've remarked that all these all computer made boats look the same. And it's a s*** to build with all these lines that do not want to flow.

 

Nice little boat, I like it. You have taken a good way to proceed with your design. Yes it's wise to have 2 false "keels" with replaceable straps of aluminum 3/16 (it not corrodes...) so the boat can sit down at low tide. As the boat is a displacement one, the false keels do not cost speed and often improve the handling.

 

Words of practical experience...no computer will tell that. You can even use this effect to get a nicer boat at the topsides and better water entries.

Making a model at scale with aviation plywood shows at some extent that straight edged bulkheads are often not the best design, and permits to redraw the bulkheads. The curves are very simple to draw as they are almost identical with those obtained with a simple batten.
If you try to force the plywood with plenty of screws on the straight edged bulkheads the result will be rather ugly...

 

I am currently investigating the limits of tortured ply, which is an area where FreeShip cannot be trusted. In the plank developments window it states the max edge error which equals stress according to the manual, and also advises the number of iterations required to minimize the error.

I have 2 versions of a FreeShip design for a Wee Lassie. In one version I combined the bottom plank and garboard into a single wider plank since they almost parallel at all stations. However those planks have severe twists. Suspecting old man Rushton knew a thing or two I tried it in half-scale.

Sure enough when I tried to form the bottom with a single wide plank the bend was very difficult and resulted in excessive force and gross distortion. So I separated the wide plank into 2 planks again, which resulted in a much easier build.

Not surprising, but the interesting thing is what FreeShip makes of it. According to FreeShip the "edge errors" (i.e., stress) is greater for the original (a la Rushton) version than when I combined 2 planks into into one; also the number of iterations for the more difficult version was resolved in less than half the number of iterations. Whatever freeShip means by these data, they are useless.

Which means that, for any design made in FreeShip that is likely to have difficulties as a build, one is advised to make a model first . . . a proper wood model mark you, not cardboard or a half-hull model.

 

If the bottom or sides of a boat are true developable surfaces then in general transverse frames and bulkheads will not have straight edges.

One of the special cases which makes this "in general" rather than "always" are bottoms with constant deadrise and sides with constant flare.

Edit: Good, appropriate computer software properly applied will show this.