Hull scanning

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14 years 7 months ago #3826 by [email protected]
I'm told that it's relatively easy to scan large 3-D objects these days and that it's frequently done in the automotive industry.

It would be useful to able to scan and profile hulls... to see whether a hull had been copied from an existing design.

Anyone have knowledge or contacts that could help with this?

Rob

Currently Fenn Swordfish S, Epic V10 Double.
Previously: Think Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...

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14 years 7 months ago #3827 by YBA/Jim Murray
Replied by YBA/Jim Murray on topic Re:Hull scanning
Companies making large parts of carbon fiber for aircraft have the equipment. I believe its used for checking plugs/molds, as well as finished parts for accuracy.
Someone building large racing sailboats may have it too.
I use the term scanning rather than probing because the latter reminds me of an overdue medical procedure. :(
Jim

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14 years 7 months ago #3828 by jbrings
Replied by jbrings on topic Re:Hull scanning
I think clones of just about any product are unavoidable and very difficult to combat, especially considering a globalised economy regulated by different legal parameters as you move from one country to another. Yes, clones are often cheaper - no R&D costs. Yes, people buy them, but in the end it's more than just the ski that makes people buy a ski. Amongst some of the factors also considered by buyers are: the brand, the customer service, after sales support, community support. I think that any company that can offer all those probably would not bother with copying anyway. For example, Europe is experiencing an influx of clone automobiles: BMW clones, Toyota clones, but is does not stop people from buying BMWs or Toyotas. Too often customers are not seen as being discerning in their purchasing habits, but that is a miconception. I do not think that cloned skis represent such a dramatic issue for ths surfski industry. To avoid misunderstanding - I do not agree with cloning, but I think it's unavoidable.

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14 years 7 months ago #3829 by [email protected]
Replied by [email protected] on topic Re:Hull scanning

I think clones of just about any product are unavoidable and very difficult to combat


No harm in trying though!

I do not think that cloned skis represent such a dramatic issue for ths surfski industry.


I'm not so sure about that. I hope you're right, but if a big player (i.e. a big manufacturer with large scale capacity) were to come along and flood the market with cheaper product, then it would undoubtably damage the guys who produced the originals.

Anyway - I'm just curious as to whether 3D scanning is viable.

You're right in your assertion that copying is hard to combat - the only way really is to have a reliably and accurately informed market. Then the consumers can make their own decisions.

At the moment all we have is "it looks similar, therefore it's copied".

But if you could see that the hull profiles were identical, it wouldn't matter what changes had been made to the deck for example, the consumer could still make his judgement - do I want to buy a product that has an identical hull to the XXX which I know is an original boat?

Just after accurate information, that's all!

Rob

Currently Fenn Swordfish S, Epic V10 Double.
Previously: Think Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...

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14 years 7 months ago #3830 by jbrings
Replied by jbrings on topic Re:Hull scanning
Agreed. Sorry about that. I was still thinking of that "other" thread.

Will keep a heads up for such a solution. An alternative cheap method may be to photograph the various segments of a ski from all angles using a digital camera on a stand and then create a CAD model based on that. I am sure that is possible.

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14 years 7 months ago #3831 by postal256
Replied by postal256 on topic Re:Hull scanning
Sure, scanning is possible. Laser scanning is usually reserved for smaller items and can be very expensive. I know a guy who uses a Polhemus scanner for small objects and I think it cost $25,000..he does reproduction furniture. You could almost certainly scan in multiple times and stitch the whole hull back together in the computer. You can also 'probe' and hull with a cnc router, but the boat typically has to be able to fit under the gantry, and it takes a long time unless you use a coarse sampling distance.

Seems to me that if you got the 2 boats side by side, you could make a big profile gauge www.fine-tools.com/k309631.jpg and a couple long flexible tape measures and you could figure out pretty quick if they were the same.. for alot less money and effort. Even a relatively coarse profile gauge made from wooden dowels would probably give you a pretty good idea.

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14 years 7 months ago #3832 by YBA/Jim Murray
Replied by YBA/Jim Murray on topic Re:Hull scanning
A market flooded by cheap product will definitely impact the large, maybe all manufacturers in the short run. The trick is to consistantly build a quality product. That product has to be free of defects for at least the warranty period. It won't take many major problems to ruin distributors and builder.
Also, reputable surfski manufacturers are constantly innovating- because they have the people who can innovate- paddlers.
A copy builder may have no long term advantage because he will unlikely be current with critical innovations that make a builder competitive.
To me, the whole business of copying surfskis is a precarious one.
Personally, I would prefer to spend the extra money on a boat that I am sure will get me out to sea and safely return.
Jim

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  • StuartXpat
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14 years 6 months ago #3838 by StuartXpat
Replied by StuartXpat on topic Re:Hull scanning
Scanning or probing is possible but expensive as pointed out above. A far easier method would be to mark stations along the hull and lay strips of glass over it supported by plywood cut outs. Then compare to similar station on the other boat. If you made up a set of forms for a V10, V12, Elite and Mako 6, you could do a quick check on any new comers. You would also need a long straight edge to check rocker dimentions.

A low-tech aproach but very cheap and practical.

BTW, if someone was going to copy a boat, they would simply pop a mould off an existing boat, I am sure they would not go to the trouble of scanning and CNC cutting a new mould.

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14 years 6 months ago #3851 by PeterG
Replied by PeterG on topic Re:Hull scanning
In the USA, laser scanning is frequently used to create a 3D computer model from an existing boat hull. For a ski, the costs would not be large.

I use a service by Andrew Williams at 3DMeasure.com but there are others.

Prior to using Andrew, I used to rent equipmet and run the scan myself. Producing the 3D surface from the cloud of points requires user friendly software to minimise time at that step of the process. Andrew incudes this step in his service.

If the purpose is to compare different skis to check for a possible copy, then I would expect the best way would be to "slice" the 3D image to create a series of sections through the boat much as StuartXpat discusses above with a manual process.

I have placed two 3D CAD models, one on top of the other before, each model in a different color. You can quickly see where one or other model is larger or smaller etc. but it is not until you slice the two models and lay the equivalent slices on top of each other that you really get to understand the details.

Labour rates and skill with either manual or computer method will determine which is less expensive. Under similar conditions, the cost and time to produce results would be similar. The benefit of the computer route is that you then have a 3D model to run additional hydrostatic calculations etc.

I am not in favor of cheap copies. It does not seem fair to those who labour long and hard to improve a hull shape. In the long run, acceptance of cheap copies will tend to limit development on new and inovative hull forms.

Peter

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14 years 6 months ago #3861 by rojo
Replied by rojo on topic Re:Hull scanning
Laser Scanning is not necessarily expensive or difficult.
I read various articles in computer or photo magazines about the topic and a number of low-tech solutions can be found together with complete instructions on the web.
Normally these are targeted at the amateur user and the scanning of smaller objects but with some tweaking and testing large objects have been scanned quite successfully.
The part that becomes expensive in my experience is the handling and evalution of the results.

One example of a low-tech scanner which can be built with amateur equipment and used at home can be found here: www.david-laserscanner.com/

Cheers, RoJo

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14 years 4 months ago #4014 by rambo
Replied by rambo on topic Re:Hull scanning
Another low cost way is to place contrasting (different colour than the hull) electrical tape, pin-striping tape or simliar across the hull at 100mm spacing. You then take a photo from either end, import in to photoshop or similar remove the hull using keying so that all you have is a transparency looks like a backbone. You can then overlay that on a photo of suspected clone ski take from a similar angle.

Cheers Rambo

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14 years 3 months ago #4030 by michielv
Replied by michielv on topic Re:Hull scanning
robin.mousley wrote:

I think clones of just about any product are unavoidable and very difficult to combat


No harm in trying though!

I do not think that cloned skis represent such a dramatic issue for ths surfski industry.


I'm not so sure about that. I hope you're right, but if a big player (i.e. a big manufacturer with large scale capacity) were to come along and flood the market with cheaper product, then it would undoubtably damage the guys who produced the originals.

Anyway - I'm just curious as to whether 3D scanning is viable.

You're right in your assertion that copying is hard to combat - the only way really is to have a reliably and accurately informed market. Then the consumers can make their own decisions.

At the moment all we have is "it looks similar, therefore it's copied".

But if you could see that the hull profiles were identical, it wouldn't matter what changes had been made to the deck for example, the consumer could still make his judgement - do I want to buy a product that has an identical hull to the XXX which I know is an original boat?

Just after accurate information, that's all!


First, I would like to say that I do not approve of copying and prefer to paddle original designs. Most of what I say below refers to kayaks but is equally applicable to surfski's. The kayaking world would not exist if it weren't for (licensed) copies. And to make sure: I paddle an original Struer CleaverX, in case anyone wondered ;)

Back when I started out (1983) there were lots of small local kajakbuilders over here in Holland (Europe) and basically you could what area/region people were from (and sometimes even the exact club) when you knew the brand of their boats. Top paddlers (or at least more ambitious ones) always paddled more expensive boats like Struer, Kirton (who started out building licensed copies of Struer!) etc.

Nowadays people can either buy an original Plastex/Nelo/Vajda/Epic etc. race kayak or a plastic tub. There are hardly kajaks available for people who want a reasonably priced boat. In fact, I would rather have a licensed copy made by a local builder than just another ski/kayak made in China and transported across the world (think of the environmental costs! It's not just money we're talking about). With the emphasis on "licensed"!

If more people would (be able to) buy licensed copies rather than illegal ones it would be best of both worlds for those who can not or do not want to afford an original. No need for measuring and whatever anyone can come up with. Besides, I think all these measures will only cost more money, therefore increasing the prices and making illegal copies more interesting for those with a smaller budget.

As for the phrase:

it wouldn't matter what changes had been made to the deck


It may very well matter what changes have been made to the deck: what if the ski with the changed deck was a significant improvement on the original and the original builder would actually take that idea and improve his own model? I've seen it happen in polokayaks and who should be paying whom?

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14 years 3 months ago #4034 by rambo
Replied by rambo on topic Re:Hull scanning
Another useful way to check the profile of a hull. Unfortunately it's also the way a hull can be copied.

www.holzcanadier.de/html/bootsvermessung.htm

Cheers Rambo

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