lofting basics help

I wonder when designers with a stock portfolio will start selling CD's with math data rather than a number of sheets of paper? A very succesful designer in Maine told me that the builders of custom boats in Maine want math data for a design rather than a table of offsets. Even small builders appear to now have molds, templates, etc cut by a CNC system.

One question about "full size templates" - what material are they furnished on? Is it a Mylar/polyester for stability rather than paper?

 

I have heard of both mylar and paper.

I was thinking of paper and using an optical oxy/acetylene table. Black ink on white paper is easier for the photo eye to follow. I have used white cardboard with sharpie felt pens too. You do have to watch your paper though, too much bleeding from inks make for a fuzzier line. The photo eye may break the path on a tighter radius. I do think you could also glue to a blued plate and scribe and center puch for manual plazmacutting or oxy/acetylene. But remove the paper, phew alot of smoke Heh!

 

You and me both. The problem seems to be fear of stolen plans. When I wrote to two suppliers of paper plans, to build two small boats - I said that I didnt fancy having to loft, then cut by hand, multiple narrow planks based on offsets that went to 1/32" .

Both of them declined to provide a cnc cutting file at any price (which they used for their kit production) , but both were too far away to supply pre-cut kits economically.

Essentially, they gave up a substantial sale, in a marketing area too far away for them to service anyway, for fear of design theft.

 

Why not configure the design as an application installation program that can be sent over the internet which, once run, deletes itself leaving files all over the place with essential entries in configuration files without which the application will not run. It's very difficult transferring a favorite application to a new computer when the old one is being dumped, without buying a new licence, as I have found out.

 

Hmm .. cant see it working for boat designs. When 'once run', what if the application didnt work that 'once' - cnc router failure, misplaced material, broken router tool, power failure in the workshop halfway through the cut.

What if you have to cut the same file twice ( on two different panels ), what if the connection to the cnc router failed etc etc. generally the file can be saved as G-Code once in the router, independant of the original application, and run or saved as many times as you want.

Lets face it - once something is stored on disk - it can be 'unlocked', hacked, distributed etc etc - just ask Sony and any other 'locked software' vendor.

The big question is - do a dozen sales in a remote geographical location justify the risk of your creative work being spread around the world for free ?

But then, anyone who buys a kit, or even a secondhand completed boat can replicate that design within days. It just takes measuring the hull, feeding the offsets into $150 Delftship, printing the expanded plates to dxf file, and feeding those files into a cnc machine.

I notice one of the vendors I contacted about cutting files last year, and after explaining the ease that his designs could be copied anyway, no longer offers plans for sale at all - only kits.

 

What seems to be forgotten and not being discussed in this thread is that no matter how accurate the CNC cutting is the pattern will not fit. Why? because the profile is usually taken at the center of the station. When the framing is cut from say 1" thick stock, it will be square to the edges. During fairing however, you will find that as the battens curve forward and aft, the pattern will only be true at the center. The back portion will need some bulking and the forward portion will need some trimming. Remember the only correct outline is only as thin as the mylar.

What I do is allign the edges of the frames to the center of the station. That is all the forward sections gets aligned at the back edge of the frame and all the back frames align at the front face of the frame. You have to determine where the stations start sloping forward and where it starts sloping backward. Then you only have to trim whatever is sticking out.

No problem on constant cross sections and barges but on a nicely faired hull, it will never happen.

 

That's not what I meant. The installation program is a run once deal, it installs the application in your computer and that will run as many times as you need, but you will not be able to copy the application to another computer. You need a licence to make it work. The licence arrives by email and will only activate the application in the computer it is sent to.

There are lots of applications being sold over the internet that work like this, and the updates to your operating system are handled the same way. About 30 years ago the PC's OS came on a diskette which would run on any computer, but not any more.

 

I always thought this a was pretty obvious way to setup the frames - by allowing for one frame face to be right on the line. Certainly, my NA did my framing plan that way years ago.

There is nothing to 'trim' if you do it the 'other' way - all frames forward of the widest section of the boat should have their bow facing surface, 'on the line', and the rest of the frame behind the station. (reverse on frames behind the widest station of course)

That way, any stringers or panels only have to touch the one edge ( on the line ). If this is causes a problem ( like causing an unfair bend when fastening to the frame) - you can fill in the gap behind the stringer or panel to prevent distortion when fastening. For epoxy fillets, it actually makes a better join, and maybe for welds in steel and aluminium - though I think they have to have an even broader angle, and dont always have frames abutting the hull.

If you want to talk about 'unsaid problems', what about the fact the most cad software treats all material as being very thin. So, if the hull thickness is 15mm on the bottom, 12mm on the side, and 10mm on the deck, the bulkheads shape has to be manually adjusted with a 'let in' by the requisite amount, so they will fit inside the hull. Multiply this by multiple bulkheads, fixed furniture etc - its a big headache if you want to cnc all the components.

Anyone know of a design package that doesnt build all boats out of 1.5mm Mylar ?

 

I understand all that, having been in the IT industry for 20 years, but thats not really a solution either. It may run on only one computer, but whats to stop it being run on the one computer multiple times ? I can make 30 canoes in one shed, instead of 1.

Then there always has to be a method to move it to another PC, in case the assigned computer crashes before the user has completed the boat build. Anyone who has been through the Autocad debacle of having to move the application to another PC will know what I mean.

Even the 'dongle' based apps can have the dongle passed around the community. And, ( surprise, surprise ) there is hardly any application that hasnt been 'cracked' to remove all restrictions - try googling for the unlocked version of any software you can think of.

 

- nothing. Nothing to stop you building more than one boat from paper plans either.

 

Thats true - but my main issue was having to avoid the major time sink of lofting and cutting that cnc files do.

Paper only 'appears' to reduce multiple builds, when in fact it can be 'digitised' very easily.

So, to refuse to supply cnc files, the designer just misses out on income under the illusion that he is somehow protecting his design.

 

Design security

If you know how to loft, generate scaled fair frames and fully understand 3/D geometry, you are not usually of a criminal bend IMHO. Those are high value skills requiring discipline.

I may be wrong and about to find out since I have a builder re-creating a design of mine with full-size templates.

 

I think in general you are right.

We get the very poor small boat builder who is eager to not even pay $40 for plans - he might do a deal with his mate, or two - but the number of boats that get built would hardly be a major problem.

In fact, if the designs were that popular, it may even generate more sales than were lost - a bit like Microsoft supplying "Educational" versions of software.

The only big hit might be if a commercial builder started doing large production runs - or re-selling the plans under their own name.

Even that is no big deal, unless it competed with the designers own sales in their area. If say, a Canadian design was replicated in say, China - what has the designer lost ? They would never have built a market in China.

The smarter thing to do might be to give away the designs, and concentrate on 'How To" books, technical advice and personal consulting etc. A lot of software makes people millions like that.

 

Since this got side tracked to theft of design and cnc incorperated into plans here is something to ponder, a double standard? In Canada I believe intelectual property in it's original form is covered automatically by copyright. here is the double standard.... I believe you only have to alter the original property by 10 percent or greater to claim it as your own. I'm kinda going from memory, if someone from Canada is here and knows different by all means correct me. How is the laws in your country/countries?

As for CNC it should bee added cost. Manually doing g code is a major pain and really boring. If you generate it from a CNC program by bringing it/ importing it in from cad well you have to cover the cost of the cnc 3D software. Even though a 3D cnc program speeds up the process tremendously, there still is a great deal of labour involved. I am more comfortable talking about Mastercam * which deals with milling and lathing processes. Tool choices , feed and speed is for every last path is the time consumer. I guess simple plasma or water jetting is much simpler than machining. However labour still must be charged for some computer time transfering it over to a dedicated cnc program.

I think I stated I was willing to pay $1000 to $4500 for stock plans for a 35-46 foot trawler. I have seen most stock plans fall in this range so far. What gets me is some charge an additional $500 to $1000 for the CNC code. I could live with this but on the other hand on a particular boat design that I like the cnc files are an additional ..... GET THIS..... $ 42000 !!!!. I could buy a cutting outfit , welding machine and a plazma and a good portion of the steel for that price! I think I could actually purchace a 10' X 10' cnc Oxy/ Acet. cutting table under $42000 ! I would pay a resonable price for nc codes knowing something about it but that is clearly way to much for a one time builder.

 

$500 - $1000 , well maybe - but $42000 sounds a bit over the top. If the plan licence permitted ( which I bet it doesnt ), you could get someone to create the cad drawings from scratch from the paper plans for a third of that.

Even if you did ignore the licence conditions, and make your own cad files just for your build - its unlikely that you would get apprehended, and would make the job so much easier.

I guess they are relying on the time it takes to measure and cut manually being more than $42000.