CNC cut parts.

[ChaseKenyon]

I have a friend who has a custom stair making company.

Most parts are made on a huge 20 ft long air/vacuum table router cut machine with auto bit/tool changing.

I am wondering as an approximation how many designs are currently available with CNC files or E drawings and/or solid works files.

I am wondering if he should look at our market as a way to get a second shift out of his capital equipment.
Is it worth his looking at this market?

CHase

Oh BTW he already has a degreed shipwright (CT) who is on his full time staff making and installing stairs.:)

[ewsponberg]

I am working with a builder in Wisconsin who is in the same situation, using a CNC machine to make airplane wing kits. That's his regular business. But he and I are developing (he mostly, since he owns the machine) a 19' barrel-back mahogany speedboat kit wherein all the parts are CNC cut in 3D. The first full kit should be ready for sale by autumn. His motivation is exactly as you describe, to keep his machine busy in a larger market than airplane wings. We hope to develop a smaller design of about 11'+ this winter which would be a good starter boat for do-it-yourselfers.

A really good example of CNC machined parts for boats is Chesapeake Light Craft--all kits are CNC cut. It's a good business if you put together the right designs and the right marketing.

There are some designers who make a living selling kits this way. The variety is not huge, however, and that may be caused by a number of factors, not the least of which is that it really takes a lot of time to plan out all the parts to be made, and having made that investment in time and money, to actually sell kits, and kits that people want.

Eric

[rbgarr]

A UK company offered a garvey-type, CNC-cut kit a while ago that used 'tab-insert' methods for a number of joints. It looked like an interesting method and design, but I haven't seen much about them in a while.

[donald branscom]

Many steel boat designs can take advantage of this as well - and do.

[rbgarr]

(ns)

[brad9798]

Calkins does, I think!

[David G]

Calkins does, I think!

Mr. Calkins has passed away, but Bill - who bought his business a few years back - has developed cnc cut kits for the smaller two Bartenders, IIRC.

[paladin]

There's an outfit in Virginia that does it on the side....actually, it's his full time business, but takes in other stuff to pay the bills. We had discussed (please don't hit me) plywood Ski-Doo kits for use with a small outboard...and a lapstrake dink.

[TerryLL]

Back when I was working aluminum, many of the boats we built came in the door as a precut kit. Quick assembly, no waste, no pile of patterns to maintain, and a wide variety of designs to choose from. What's there not to like? And there were plenty of ways to customize the boat in the cabin and deck layout.

But just because you can crank out a lovely design as a precut kit does not insure you'll make any money at it. The success of outfits like CLC is in the efficiency of their operation, and their marketing.

[SMARTINSEN]

Of course CLC does this with their kits.

[JimConlin]

How ever many designs are available as cut files, I expect that there are many more which were developed in a CAD system and could be taken the next step with modest effort.

[py]

Maybe a bit off topic, but I was watching the teev last night, a UK show called Grand Designs. This one was about a farmer and his wife building a new house on their farm. They commissioned a spiral staircase to be made by a boatbuilder friend-turned-artist. Cost them 40,000 pounds!! Looks like there might be better money in staircases than in boat kits!

[andrewe]

Jordan boats in Scotland do kits for Oughtred, Dix and other designers. They used to build boats, but I think mostly concentrate on the kits now. If you want a one off they will digitalise the plans (with the designer's permission) and add it to the list.
I looked at one and it was actually cheaper to buy and ship the kit to here than buy the recommended no of sheets at the local high prices. Also carefull arangement of the cut pieces saved several sheets over the designer's numbers, so along with their bulk discounts it works well.
A
www.jordanboats.co.uk (http://www.jordanboats.co.uk)

The slot and tab mentioned might be www.whisperboats.co.uk (http://www.whisperboats.co.uk) who market the australian scruffie designs.

[24hacker]

I recall a couple of gentlemen from Holland that were cabinet makers that made Chris Craft runabouts using a CNC - they have posted on here.

[G. Schollmeier]

The work for this kind of stuff is mostly on the front end. The design is broken down into parts and the CAD files created and nested for efficient use of stock. The machine cut time is very short. I know a few cabinet shops where their machine sits idle most of the week. But any added work helps. Files of this type are not easy to find without a cost.
Gary

[ewsponberg]

How ever many designs are available as cut files, I expect that there are many more which were developed in a CAD system and could be taken the next step with modest effort.

I have had a number of clients hire me to make the AutoCad patterns for their hull lines, from small power and sailboats to a 55' power catamaran. The latest one was for a 45' sailboat for which tooling is just finished a few weeks ago. Most can be done for between $500 to $1,000. From my patterns, which I can deliver by email in a number of formats, the client will have the patterns cut by someone who has a suitable CNC machine. I can also plot to Mylar so that the client can hand-cut them himself. This seems to be a small but regular growing business in the last few years.

Eric

[obscured by clouds]

A UK company offered a garvey-type, CNC-cut kit a while ago that used 'tab-insert' methods for a number of joints. It looked like an interesting method and design, but I haven't seen much about them in a while.


Rob Humphreys design had a CNC tab kit [marketed as Prefix] for the H22 sportsboat. Rob has kept his interest in this because it can be tailored to a custom build in order to lower costs and to have a self jigging set up for home builds.

http://www.robhumphreys.com/Media/Images/H22/prefix4%28256x160%29.jpg

http://www.robhumphreys.com/Media/Images/H22/prefix2%28256x160%29.jpg

http://www.robhumphreys.com/Media/Images/H22/h22_2%28256x160%29.jpg

http://www.robhumphreys.com/Pages/Design%20Archive/104%20H22.html (http://www.humphreysdesign.com/)

although he's been heavily involved with the British AC campaign of late and has a couple of superyachts to finish he is still very interested in the Prefix concept.

[andrewe]

Steven,
You have a point, the ed. of Classic Boat said " Don't train to be a boatbuilder, go and earn a lot in the city (it was a few years ago) and employ the few guys that the industry can stand"
Andrew

[ChaseKenyon]

" Oh BTW he already has a degreed shipwright (CT) who is on his full time staff making and installing stairs "

you may have answere your own question right here.

i dont see there being a very large market for wood boats and believe the market is probably already past its saturation point. the poor economy doesnt help
http://www.woodenboat.com/forum/images/buttons/quote.gif (http://www.woodenboat.com/forum/newreply.php?do=newreply&p=2266308)andrewe


one might be inclined to think that way.......

But WBM and Carl and others have put their faith into future home buildable boats that are efficient like we had in the 50' and early 60s


Spent summer after summer in camp grounds as mom felt it was an easier environment to take care of 3 boys and their buddies. We saw all kinds of boats and fully 2/5 or more were home built.

50 hp was a really big deal. most of us learned to water ski being 35 and 40 hp boats.

so I personally believe that we are headed by the economy back to boats like that. Even Chris Craft offered Kits.

now the main problem in this day and age is over specialization in our species. This is born out in the engineering real by the difficulty in finding true sytems engineers that understand electrical mechanical and controls and software systems all at once.

So the average home owner potential boat builder has les than hlf of the skills the average homeowner did then. (It was ungeard of then to hire a painter to paint your house or a cabinet builder to make library shelves for you den.)

On the other hand we have the technology to make up for the lack of tools(every family in the 50s early60s had skill saws and a table saw and more in dads section of thebasement). the average homwoner like I said now longer has those tools to build from an article in Popular Mechanics magazine. On the other hand we have the technmology for al of the would be builders to have someone local like my friend precut a kit tha can be picked up with a coupple of pickup truck loads, andthen assembled.

What we have in tab and slot Ice cube tray de3signs and in stitch and glue and even in origami typ folded ply hulls and boats could not have been imagined back then.

Now with a screw gun and a $40 dollar WallMart orbital sander anyone can build their own boat.

I personally think the economy is long overdue to head back to this. I have seen it even before the big stock and banking debacle already on a big upsurge.

so I think this is, IS , the wave of the future.

I personally and any of my past customer who would follow my advice would not spend money if possible on a set of plans for a build if solid works or similar files were not available to hve the parts CNC cut. I am verey good after years of engineering and then cabinet making and then solid surface counter fabrication at minimizing waste. But I can not begin to compete in that vein with a good CNC program. so I wold stilldelivr my material to my friends shop and then pay him to maximise the out put and have him precut everthing on the CNC.

EVen a traditional Batten Seam Hacker of Gar wood Runabout will go together easir and come out better to a point that more than justifies haveing Dan and Paul cut the wood for me on the CNC.

So that is my take on the future and I do see a strong economy driven comeback for home built plans and kits ove the next ten years.

A key driving force behind this will be the fuel economy and speedof a 50s or 60s style planing runabout outborad or inboard as oppsed to the rampant (78% of all undr 25 ft boats sold) deep V hulls. They are always plwing throught the water in a big hole making shore damaging wakes and worse and maxed out fuel consuption as this is what the boating industry has made the standard. So Now we have these folks setting arbitrary speed limits on lakes of 30 mph to 40 mph, a speed at which they are not comfotable driving and at which their Deep V is still not out of the hole. this is all that is being offerd to the public. So all these deep Vs make all these wave so the uneducated boater is easily convinced to by a bigger more pwoerful deeper V to make outings more comfortable for his or her family. Which leads on and on to bigger deeper V hulls which lead to bigger deeper more shore damaging and navigational damiaging waves, in and endless cycle.

Winnespausaukee in the late 50s and early 60s had lots more bots on the lake than now. But the non boating folks tha can buy on the lake buy what the indutry sells them. Back then you could have run a pontoon deck anywhere on the lake. Not now. So what they have done is set an arbitray speed limit which will guarantee that all the newer Centurys, ChrisCrafts, SeaRays, Regals, and Four Winns will slow down to their maximum(great for wake boarding) wake generating speed, with the boww at it's highest possible position detroying all hope of forward vision.

THere were more boats on the lake back then than now, but the lake was not churned into deep V wakes either. You could run the whole 26 mile long lake in a Florida Everglades Air Boat with no problems (done it).

Because so many of the boats wer home built and so many wre owned by past whome builders there was much higher average levelo of "Seamanship". The Current required course / exam only deals with the laws you can break it does not deal with seamanshipo and respect for the water and sea or lake, let alone other boaters. So if you have never driven a boat, you can go to an 8 hour course and pass the simple test on the laws and go out and (unfortunately most do ) think you can now handle a 70mph super boats. Not good. Wife and I own an ex racing Audi and a special LMTD edition 400hp Jaguar. Neither of these should ever have an unqualifed driver behind the wheel. We both have SCCA experience and driver training. Same for boatsshould be the rule. But now we have made a minimal standard that if you sit in the class for 8 hours you will pass the test of legal issues but still not even know how to approach the dock.

NH covers that but only if an I/O or outboard, What they say about inboards assumes that all inboards are single engine right hand propellors without centerline offset shaft or rudder as ws commonly used by ChrisCraft, Century, Shepherd, Gar Wood, Lyman,Dichtburn and probably 90% of the classic boats. If you do what they tell you to do with any of these offset boats What they teach will guarantee that you will crash into the dock.

So much for gov't taking over marine education and drivers licensing.

So now that I have unloaded a major peeve of mione, back to the original concept.

I think the future is about to open up big time for home builts and boats like the recent ProfessionalBB designe competition.

That is why I believe that CNC shops have a future like the local piece work machine shops of the past, and they may have a come back too.

CHAse

[Ray Frechette Jr]

To add to this discussion it must be realized that there are CNC kits and there are CNC kits.

Two different people could take the same desing and creat two different CNC kits where one wouldbe vastly superior.

If one simply takes the Stitch and glue plans and creates perfect cutouts of the parts as drawn, OK, There will still be ample need for the builder to have aplane and lnow how to use it to fine tune the fit and use some knowledge and thought and also to know how to fair etc.

With straigth stitch and glue one hull to the next can still vary a fair amount dependinng on how much tweaking goes into the hull before gluing.

As such the internal panels may need significant modification form boat to boat.

A far better and more valuable kit involves a complete redesign of the kit to take advantage of the utility of cnc.

Features such as step scarfs for reliable and accurate registration of panels in glue up, geared chines that interlock as the panels are stitched together to get proper registration between panels and ensure 100% fair chine lines, tabbed and slotted internals and bulheads to ensure proper registration of those pieces as well.

As a builder for hire I have plenty of experience with laying out and cutting out panels by scxratch and tweaking and sdjusting to fit.

If I have the option of doing it that way, or paying $60.00 a sheet more for a CNC kt with such features the kit s the way to go.

Labor savings pay for the cost of the kit.

Once such a kit is stitched up it is virtually perfect with absolutely minimal tweaking needed and the internals fit in with no adjustments needed.

I can have someone stand atthe end of a 17 foot long by 6 foot wide hull so stitched with no internals in place and before gluing it together we can lift it from the ends, move it around the shop and set it down with no appreciable change in hull shape.

Try that with a stitch and glue hull you get out of ply stock yourself and stitch together....

[andrewe]

Chase,
I was just pointing out that the reality is that kits are the way to go, as true shiprighting is just too labour intensive to be affordable by average people ,who have to employ specialists. The 40,000 stair rather illustrates this.
I admire the Spirit lot and their lovely boats, but way out of reach for 98% of the pop.
A

[ChaseKenyon]

Ray and Andrew,

Thanks so much for your input.

I started this thread on a very personal note.

My feelings at this point are keeping it alive in the hope that we can be an adjunct to the design contests and articles in Pro Boat Builder and Wooden Boat magazines.

I live on the state highway four miles from Lake Sunapee. Like living in a fishbowl LOL. I can not tell you how many times I hae hears WOW that is a gorgeous boat you are building! I wish I could build a boat.


So I think the desire is there with the public. As to the means,,,,,, $5000 for a used running boat at the marina Let alone $12000 to 25000 for a new boat is beyond the means of most now. But,,,,,I have never had one of my Glass Lapstrake convesions to center console fish boat at $1500 to $2500 with old motor and trailer sit in the yard for sale more than a few days. And it only took one week (once when I needed money) to sell one once during Thanksgiving week.

So I think there is potential but most folks like the ones who stop by the yard do not know they can build a boat. I totally agree with you Ray that tabbed build is the way to go. Funny, Dan and Paul build most of thier complicated showpiece stairways that way.

Chase

[JimConlin]

If your only tool is a hammer, everything looks like a nail.

My concern about the kits I've seen is that they reflect their makers' limited armamentarium of tools.
Seems to me that they have only simple 2-D CNC routers and all they really can cut is 1/4" or 1/2" okoume ply, so instead of proper tapered scarphs , we get weaker step scarphs and lapstrake bevels are replaced with weaker (but patented) rabbet joints.
The technology is fine for stitch&glue kayaks, but less so for larger boats. I'd love to see someone invest in the equipment to cut true 3-D shapes.

[ChaseKenyon]

Ray just had a thought as SWMBO walked in..........


So you think we could use the power of the internet and become the overly vocal minority and then create a situation where it was expected of designers to also have Solid works or similar or even CNC files for tabbed construction of frames and all plywood panels?


It's a given in our world that the sqeaky worm gets all the attention. The louder the squeak the more attention. We here at the forum already have a serious involvement with Pro Baot B and Wooden boat and Classic boat. So we are wether true or not percieved, PERCIEVED, by the masses as those with years of expertise in boat building and wood boatbuilding especially.

Add all those who wish they too could build a boat and we have a formidible crownd to virtually demand designers have tab and cnc available for designs.

Just a thought.

CHase

[Ray Frechette Jr]

My concern about the kits I've seen is that they reflect their makers' limited armamentarium of tools.
Seems to me that they have only simple 2-D CNC routers and all they really can cut is 1/4" or 1/2" okoume ply, so instead of proper tapered scarphs , we get weaker step scarphs and lapstrake bevels are replaced with weaker (but patented) rabbet joints.
The technology is fine for stitch&glue kayaks, but less so for larger boats. I'd love to see someone invest in the equipment to cut true 3-D shapes.

If you have multi stepped scarfs I don't think they are any weaker than tapered scarfs.

I will grant you that if your step scarf is more akin to a shiplap jpoint it is weak, but if you have somewhere around 10 steps on a 6 mm panel you have quite a bit of strength there.

And to be truthfuill, the scarf only has to be strong enough for the job. That is the Naval Architects job to determine.

Step Scarfs have the advantage of proper registration to ensure the panel is the exact dimension the designer drew out. With beveled scarfs of which I have made my fair sahre of it is easy to be off by a few mm. To That end I generally scarf the panel first and then layout the panel.

As to lapstrake bevels, there is no need to have rabbetted bevels, you can have them beveled. CLC has the patented lapstitch method. Graham Byrnes of B&B is working on a kit for his Lapwing design that you have a slotted jig that you assemble and build on and you can plane down the bevels yourself.

Before anyone gets all high and mighty about traditionalism, million dollar boats by big coompanies are built of marine ply with extensive use of CNC cutting of frames and such to make fairing go faster in the end. It's all about dollars and cents... The pro boys look to anyway to shave hrs which means either more profit, or the ability to reach price point that allows more business.

Even rich people are price sensitive. Though it isn't price sensitive like you or I know...

[Ray Frechette Jr]

Ray ...

So you think we could use the power of the internet and become the overly vocal minority and then create a situation where it was expected of designers to also have Solid works or similar or even CNC files for tabbed construction of frames and all plywood panels?

Add all those who wish they too could build a boat and we have a formidible crownd to virtually demand designers have tab and cnc available for designs.

CHase

Demand will certainly drive the market. AAs designers sense a need to provide such to sell plans, ithey will start making sure all of their plans come that way.

Be aware though that it is a HUGE investment of time and money to bring a set of plans from the drawing board to a completed CNC kit.

And to amortize that cost, you have to ensiure the boat will be popular enough to recoup that cost.

I have a pretty strong working relationship with Graham Byrnes as wellas other designers, but Graham has purchased a CNC machine and has been working on converting plans to CNC kit form.

To do so require a lot of tweaking of the panels to engineer in the geared chines I spoke about. Graham always builds a boat from the kit and twqeaks the cut files as he goes in order to make sure it works right. I think I buiilt the second CoreSOund 17 from a kit myself which was a good beta test to get a second set of eyes on a kit and I offered Graham feedback which he used to further alter the cut files a bit.

There has been demand for a CreSound 20 kit too, but one as to ind the time in order to devfote to it so that is on the back burner for now.

Graham is also in the process of developing the Lapwing as a kit noat.

I know he has the CS 17 ready to go and has been selling those and I believe he also has the Diva Kayak to kit.

He might have a Spindrift 10 too.

I have determined for myself that anytime there is a B&B kit for the boat I am building, that is the way it is going to be done by me.

As toi the thought that it makes it more accessible for the masses, Well, Yes and no.

There is still a significant learning curve even if you are not cutting out the parts. I haev had people approach me by email about it and I always ask if they will enjoy the Process.

On a CS 17, the kit probably saves me about 40 hrs overall.

Considering the boat takes roughly 350 hrs from start to finish that saves you about 1 week out of 2 months full time labor.

The home builder who is committing an average of 10 hrs per week, that brings them from about 8 months to 7.

It is not a panacea, but it is a neat help.

Even with the kits there is still a cadre of people that either do not have the time, inclination or abiltiy to build it themselves and will want to hire somebody to do it for them.

[Tom Lathrop]

If your only tool is a hammer, everything looks like a nail.

My concern about the kits I've seen is that they reflect their makers' limited armamentarium of tools.
Seems to me that they have only simple 2-D CNC routers and all they really can cut is 1/4" or 1/2" okoume ply, so instead of proper tapered scarphs , we get weaker step scarphs and lapstrake bevels are replaced with weaker (but patented) rabbet joints.
The technology is fine for stitch&glue kayaks, but less so for larger boats. I'd love to see someone invest in the equipment to cut true 3-D shapes.

Ditto what Ray said. I'm familiar with the kits he builds from the cutting end. I see that Ray chimed about Jim's concern over the stepped scarfs. I was a little skeptical at first, but the steps can be made as fine as you please, so strength is not really an issue. Further, the registration of the steps (when properly done) makes it all work really well. There are other self locking types of joints that aid in assembly and, when fiberglassed over, are plenty strong.

While actual cutting time is fairly timely, the rest of the job is not for dodos and requires some attention to detail to make the final product work well. Making the whole thing work can still be, as with all computer jobs, sometimes frustrating and time consuming while the boat builder morphs into a kit builder and may wonder just how he got where he is.

Complicated machining like Chase mentioned requires a 5 axis CNC machine and another level of investment that is not needed for plywood but would be valuable for carvings of details on high end boats. This is not new ground either.

Any preaching we might do here would most likely be to the already committed. This thing has a life of its own now and could not be stopped if we wanted to.

[Stiletto]

While visiting Australia a few years ago I had a tour through the ATL factory in Queensland. They had a fancy router setup which could essentially make a one off set of frames for a yacht with the end product being the same (or better) as those provided in mass produced kits.
All that was required was the neccessary computer generated files to load into the machine.
I was told that yacht builders that used the system estimated that on a decent sized yacht they got a two week headstart at a lesser cost on their project compared to marking and cutting the frames themselves.

[Candyfloss]

So, can I be specific? What does it take, for instance, to produce a set of molds for a little dinghy; five molds, a stem pattern & a transom pattern, from a table of offsets?

Lets go a step further, & say this is to be glued lapstrake, can we have a set of planks, say 9 per side? Laps 3/4"

Or, this is to be that (shudder) other medium. Can we carve a plug out of polystyrene or similar to build a mold over? What does it take? How much number-crunching time?

Just from a table of offsets. I'd really like to know.

[Ray Frechette Jr]

Spoke to Graham last night about step scarf vs bevel scarf tstrength.

As I suspected graham did some destructive testing on the two options before offering steps crafs in his plans.

The failure point between the two were atthe same points and indistinguishable from inspection of the pieces.

Granted he did not use lab equipment to carefully calibrate whatthe strains were on the loads, buyt his personal feeling is there was an indistinguishable difference between the two...

Also he mentions depth of cut from one step the the other is under 1 mm. IE for a 6 mm panel I thinkhe said there were something like 9 steps...

I see no reason to be uncomfortable with the strength of step scarfs, and much to reccomend them.

[ewsponberg]

So, can I be specific? What does it take, for instance, to produce a set of molds for a little dinghy; five molds, a stem pattern & a transom pattern, from a table of offsets?

Lets go a step further, & say this is to be glued lapstrake, can we have a set of planks, say 9 per side? Laps 3/4"

Or, this is to be that (shudder) other medium. Can we carve a plug out of polystyrene or similar to build a mold over? What does it take? How much number-crunching time?

Just from a table of offsets. I'd really like to know.

If I were hired by a client to make the patterns in AutoCad for CNC routing for a small dinghy, say 10' long--5 patterns--the fee would likely be a few hundred dollars, let's say US$200 to US$400, depending on the quality of data going in, and how complicated the patterns were going to be. That covers my time to do the work. This is my profession, and it is not hard work to do, so a respectable non-professional could do it for less cost if you know he or she is good at what they do. Such work could be done solely in 2-D from the table of offsets and the construction plans.

For a lapstrake hull, that is much more complicated. The lapstrakes have to take their shape in 3-D, so now you are looking in planning 3-D shapes in 2-D with the graphics and math that that entails, or, you have to model the hull on the computer in 3-D and plot the shapes from there. That's a lot more time, so you may be looking at US$1,000 or more to do the work.

To make a mold or former out of foam, you are looking at ever more time. You can start with blocks of foam glued together and use a set of female patterns (CNC cut perhaps, or made by hand) to check the hull shape at certain stations and the ends as you carve down the foam. You could go the next step and have a CNC machine carve the foam for you. For that, you need the 3-D hull model, and again, if it is lapstrake, that is much more complicated. The CNC people have to program the hull shape into their machine and then program the milling paths to make the full 3-D shape. The shape still has to be dressed and finished by hand. For this work, you are now looking at thousands of dollars of investment. If you did it that way, you would like to recoup that investment by building a lot of boats--the whole point for the mold. So now you are in the boat building business, and the mold is only a small part of the overall cost.

I hope that gives some perspective.

Eric

[Rational Root]

A company that specialises in this,
http://www.fyneboatkits.co.uk/

Another
http://www.whisperboats.co.uk/

I don't have any commercial interest in either.

I've met the guys from Whisper at Beale Park and the seemed to be good guys.

[peter radclyffe]

thanks Chase, Ray & others, i agree , in 20 years time maybe most small ,boats will be cnc, why not, for bigger timbers its a problem with timber movement, etc
progress is inevitable

[Candyfloss]

Thanks Eric, that helps a lot.

[ChaseKenyon]

I hope that gives some perspective.

Eric


My thanks to you Eric and all the other ray and more that have chimed in so to speak.

In the music industry many independent dealers have found ways to use the economy To grow and change their business models. Many have had their best Net profit quarters ever since the financial debaucle.

So I personally feel that this economy is a major opportunity for designers builders and the faithful to reach out and touch someone as they say.

I think the closer someone is to building a boat themselves the better boater they will become.

Soooo....... the Future is here and it is ours for the taking.


Chase;)

[JimConlin]

The failure point between the two were atthe same points and indistinguishable from inspection of the pieces.

Granted he did not use lab equipment to carefully calibrate whatthe strains were on the loads, buyt his personal feeling is there was an indistinguishable difference between the two...

Also he mentions depth of cut from one step the the other is under 1 mm. IE for a 6 mm panel I thinkhe said there were something like 9 steps...

I see no reason to be uncomfortable with the strength of step scarfs, and much to reccomend them.

If there are 9 steps to the scarphs, I am entirely comfortable with the method and endorse the benefit of it's being self-aligning.
My larger gripe is with the 'lapstitch' joint which is essentially a 1-step joint in the other direction.

[mick allen]

My larger gripe is with the 'lapstitch' joint which is essentially a 1-step joint in the other direction.

I wouldn't gripe too much: the glued or fastened lap joint is a common joint in all kinds of construction. Millwork comes immediately to mind.

And combining the 'gooed (they didn't have good glue – moss and mossmush) lap joint' in sewn strake boat construction is a 4000 year old technique - 'lap-stitch and goo'.
In this case (diag C ) it is to protect the joint(and stitching) while dragging over the shore (ref Ferriby boat 1):
http://www2.rgzm.de/Navis/Ships/Ship027/Image/027f1004.jpg

[stoneyreef]

So, can I be specific? What does it take, for instance, to produce a set of molds for a little dinghy; five molds, a stem pattern & a transom pattern, from a table of offsets?

Lets go a step further, & say this is to be glued lapstrake, can we have a set of planks, say 9 per side? Laps 3/4"

Or, this is to be that (shudder) other medium. Can we carve a plug out of polystyrene or similar to build a mold over? What does it take? How much number-crunching time?

Just from a table of offsets. I'd really like to know.


As long as you give me a .stl or any real 3d format of the hull, I can machine the hull in 6" deep sections of polystyrene and just glue the sections together to get your mold. The hardest part is getting good CAD work to make the appropriate 3d Model to slice and carve.

[JimConlin]

I wouldn't gripe too much: the glued or fastened lap joint is a common joint in all kinds of construction. Millwork comes immediately to mind.

And combining the 'gooed (they didn't have good glue – moss and mossmush) lap joint' in sewn strake boat construction is a 4000 year old technique - 'lap-stitch and goo'.
In this case (diag C ) it is to protect the joint(and stitching) while dragging over the shore (ref Ferriby boat 1):
http://www2.rgzm.de/Navis/Ships/Ship027/Image/027f1004.jpg
My mossmush supplier went out of business a couple of hundred years ago. For joining two strakes in a glued lap boat, I'd rather have a bevelled 1/2" or 3/4" lap than a 1/4" wide rabbet.

[John Meachen]

As long as you give me a .stl or any real 3d format of the hull, I can machine the hull in 6" deep sections of polystyrene and just glue the sections together to get your mold. The hardest part is getting good CAD work to make the appropriate 3d Model to slice and carve.

I think you may be getting the technology of boatbuilding and plastic moulding confused.In boatbuilding the moulds are transverse sections that locate the planking.

[fair&fair]

Well, you can create plastic boats from a mold no? You mean to say Wooden boat construction.

[ewsponberg]

I think you may be getting the technology of boatbuilding and plastic moulding confused.In boatbuilding the moulds are transverse sections that locate the planking.

I think stoneyreef is referring to horizontal sections through the hull, otherwise known as lifts, as in the making of a half model. These still have to be carved down by machine or by hand to create an accurate hull form from which a mold can be made. This, of course, goes into the realm of plastic boatbuilding, so it getting off topic.

Eric

[mick allen]

My mossmush supplier went out of business a couple of hundred years ago. For joining two strakes in a glued lap boat, I'd rather have a bevelled 1/2" or 3/4" lap than a 1/4" wide rabbet.
The following is probably not that really relevant with the wonderful glues we have, but it is fun to look at some of the issues of lap jointing in boat construction:

1) Simple Overlap – 1/6 restraint

The bevelled (or the very basic unbevelled) lap strake joint is the least naturally restrained joint upon construction and service. If one assigns 6 directions (3 dimensions) of freedom to the joining members, the unfastened joint’s members each has a lowly 1 out of 6 directions of movement restrained. Its strength is that the least amount of material is removed at the connection.

2) Shiplap or One-sided Shiplap - 4/6 restraint

The one sided rabbetted, shiplap, lapstitch, or 4000 yr old lapsewn strake joint is restrained in some more directions because of the friction (caused by gravity of the upper part and the assembly above) between the 2 parts and is an natural feature of the ledger effect supporting the uppermost board (whether the boat is built upside down or not). These joints when unfastened are restrained in 4 out of the 6 directions of movement - a marked difference compared to the beveled/unbevelled joint. This is a telling reason for the technique to have been used for millennia.

However the one drawback to the above edge joint is that the mechanically fastened joint is as weak as the weakest material that the fastener penetrates. In the ancient case, the planks were very thick and the sewn ‘fasteners’ penetrated a large proportion of the overall thickness thereby keeping strength up. But in the recent historical case, without glue and using thin planks, later traditional mechanical fasteners would assume to penetrate the thin lip of the rebated plank which results in a weak joint. But now that modern gap filling glues have appeared on the seam (sp!), this ancient joint’s properties become very attractive again – especially to bring the discussion back to overall topic of using CNC.

(as an aside, at what point does a CLC patented CNC lapstitch plank become a CNC rabbetted or CNC shiplap plank? – can one of us now patent a CNC butt plank (detail b)? a CNC shiplap plank (detail f)? or our own version of detail c?). Good thing there are no such thing as gains. Heh heh. Or maybe one manufacturer’s gain comes by way of rebate. (sorry, sorry!)

3) Bevel/Shiplap Joint – 5/6 restraint – CNC oriented

Because of the sophistication of the shown 4000 yr old Ferriby 1 sewn joints, I would not at all be surprised to find that these builders or their contemporaries also employed a simple modification to make the one sided shiplap joint one step more stable. (call this freshly minted, new, and copyrighted joint, the ‘Bevel/Shiplap Joint’, heh heh). If we slightly bevel the end of the non-shiplapped plank and to be on the safe side use a dovetail type bit to give the lapped plank edge a slight complementary bevel - we end up with a joint, when touching, whose members are only free to move in one direction of the six possible. Combine this with the use of modern adhesive techniques and one ends up with an interesting process and construction detailing that is based upon the amazing craftsmanship of those ancient bronze age shipwrights on the shores of the Humber River.

http://www.westcoastpaddler.com/mick/misc-dwgs/lapstrake jt types.jpg

Anyway, here’s a few diagrams of the thoughts above showing the restrained movement directions of those three types of lapping.
-mick

[mick allen]

Ray freshette jr wrote:

Features such as step scarfs for reliable and accurate registration of panels in glue up . . .
Thanks for the idea. So if no one’s thought of it, here’s couple of related CNC ideas back . . .

The KeyStep Scarf and the LockStep Scarf:

The idea is that the panels can either be self registering in both dimensions or actually locked in place for simple glue up.
Presumably the stepped buttblocks that you refer to in the stepped scarf approach are set to fixed repeatable dimensions so that one could say have a long extrusion on the ready shelf just in case the intended, exactly shaped ones go missing, heh heh.

Or maybe for speeding up the process, one could have the long butt extrusion crosswise on the bench and lay repeated panel pieces on the extrusion side by side and glue them up all at once. Then use an edge trimmer with the guide set at the outer veneer and zap the perfect edge out again . . . anyway another idea that might be applicable in some cases.

In the diagrams of below of the ‘KeyStep Scarf’ and the ‘LockStep Scarf’, the same idea continues with the dimensions of the scarf steps, register protrusions, or of the locking protrusions, being fixed or continually repeated along the buttblock so that one could also have a long ‘extrusion’ sitting on the shelf nearby in case of accidental disposure or to try assembly line time savings.

http://www.westcoastpaddler.com/mick/misc-dwgs/keystep-scarf-jts.jpg

Ideas anyway,
-mick

[Canoez]

Ray freshette jr wrote:

Thanks for the idea. So if no one’s thought of it, here’s couple of related CNC ideas back . . .

The KeyStep Scarf and the LockStep Scarf:

The idea is that the panels can either be self registering in both dimensions or actually locked in place for simple glue up.
Presumably the stepped buttblocks that you refer to in the stepped scarf approach are set to fixed repeatable dimensions so that one could say have a long extrusion on the ready shelf just in case the intended, exactly shaped ones go missing, heh heh.

Or maybe for speeding up the process, one could have the long butt extrusion crosswise on the bench and lay repeated panel pieces on the extrusion side by side and glue them up all at once. Then use an edge trimmer with the guide set at the outer veneer and zap the perfect edge out again . . . anyway another idea that might be applicable in some cases.

In the diagrams of below of the ‘KeyStep Scarf’ and the ‘LockStep Scarf’, the same idea continues with the dimensions of the scarf steps, register protrusions, or of the locking protrusions, being fixed or continually repeated along the buttblock so that one could also have a long ‘extrusion’ sitting on the shelf nearby in case of accidental disposure or to try assembly line time savings.

http://www.westcoastpaddler.com/mick/misc-dwgs/keystep-scarf-jts.jpg

Ideas anyway,
-mick

Interesting concept. I'd skip the butt block, however and make mirror-imaged pieces (male/female contours) of the puzzle so that they just lock together. Another thought is that with the precision of the CNC cutting, you could design in contact points to give you thickness for the epoxy bond-line. Once you know the ideal film thickness for your epoxy, design it right into the joint. Another thought would be to use a cutter that isn't straight sided but that has a 1° taper to allow for any fuzz at the edges of the step features. (DAMHIKT)

[mick allen]

good thoughts. I think the mirror might be tough because of the time and difficulty of register being kept while flipping the base material - but maybe do the small stuff first (ie one joint half of ea panel and nothing else) and use the edges of the overall panel for register. But if it could be done all at one 'sitting' with the head articulating over and below, that might work. Probably a time and ability tradeoff.

The lock might be enough to deal with the 'fuzz' , but another idea along those lines would be to actually cut the face veneer joint edges back to some fraction of a degree or upwards so that the apparent joint edge becomes as invisible as possible. The strength of the whole jt would be unaffected.
-mick

[mick allen]

Sorry I didn’t put down these obvious next steps – been distracted by another track of thought.
If we add the idea of registration or just maybe locking as talked about in the registered and locking scarf joints into the CNC lap joint, there is a possibility to help the lapping build possibly be even easier.

One of the difficulties with putting preformed strakes in the exact position we want them is longitudinal placement control. Sure, we can put stitches thru pre drilled CNC holes, but that is separate tooling or maybe a separate hand or a separate task to perform.

If the ancient One Sided Shiplap or the fresh, new Bevel/Shiplap joint is used, maybe the ‘third hand’ of reality or clamp or brace is all that is required, but another helpful assist might be the unmeasured assist of correct placement before even investigating stitch hole alignment - simply by feel as the new strake is bent or inserted into place:


4) Registered One-sided Shiplap - 4/6 locking

The 4,000 yr old joint can be made to register by a quick offset ‘bump’ of one cutting tool and a complementary depression of the other at one or several places along the strake edge, but hidden from the exterior behind the shiplap lip - it becomes a feature of the orthogonally faced or angle faced rebate . A separate tool could do it, but the simplicity of using the existing one is the most provocative. The very small registering bump/depression would only be visible on the inside of the vessel and could either be left, cosmetically disguised by latter sanding/chiseling, or placed in locations that are covered by other subsequent items – say seats or false ribs/frames etc.

5) Bevel/Shiplap Joint – 5/6 locking

And of course, the superior building assist of the extra locking/restraining ability of the new Bevel/Shiplap Joint can be made even more helpful with registration ability just as talked about above.

http://www.westcoastpaddler.com/mick/misc-dwgs/locked shiplap jts.jpg

Anyway, here’s a few diagrams of the thoughts above showing some possible configurations and restrained movement directions of another two new types of lap joint or at least lap joint subtlety.

-mick