Plan lines to patterns?

[sdenault]

Hello

looking for guidance
I have a set of plans for the Robb White Sportboat. My intention is to make a skin on frame version of this boat.
Being a newbie I'm not sure what is the simplest way to transfer the frame lines (boat shape) from the plans onto plywood in order to draw out the frames I'll need.

I realize I could have multiple copies of the plans printed and then just cut out but I don't have access to a large printer and I'd like to learn how to do this anyway.

Ideally I would like to end up with full sized rib/frame outlines that can be transfers onto plywood.

I realize this is pretty basic for experienced buidlers and likely has been discussed before, so just need to be guided to specific threads or videos would be great.

thanks
Steve

[JimConlin]

I strongly recommend that you find a design that was intended for SOF construction.
Your question suggests that you don't have the experience to make this leap.

[sdenault]

Thanks I guess (:

Yep, not an old timer (56) at boat building. So far just a 20' canoe and a tandem kayak, oh, plus that "Dug' of Hannu's, in the past year.

Still I've never built from a full size set of plans. So my question was about transfering lines for the boat onto plywood or lumber to get the frame patterns.

I wasn't really asking for critic or opinions, just help with practical solutions. Can anyone else help or direct me to a resource?

I'm not the kind to get overly annal about details, I prefer more of a freestyle experimental way of building which is why I like the SOF approach.

Thanks all

Steve

[TerryLL]

Well Steve, there are many ways to transfer frame patterns to mold stock and the subject has been discussed here and on many other forums many times, including a number of threads specific to the Sport Boat. A quick Google brought up a couple pages of links. Also, any basic text on boat building will explain the process.

I believe Jim's comments are to the point. If you have to ask about this very basic process, it's unlikely you have the background to convert a strip-planked hull to SOF. Your best bet here is to contact Robb for guidance.

[cprinos]

Don't those plans come with full size patterns of the molds?

If not, grab a copy of Greg Rossel's Building Small Boats http://www.amazon.com/Building-Small.../dp/0937822507 for a good explanation of lofting from plans.

SOF question is a different matter

[sdenault]

If anyone has postive or encouraging comments please do pass them along.

Come on guys, it was a simple question, not a challenge to your knowledge, experience or grand wisdom.
If you don't have the answer just say so, negative comments do nothing to encourage others to add to this forum.
And as often happens only a few remain and this is the kind of reception they give newbies.

Perhaps I've misunderstood the nature, spirit or intend of a forum such as this. What a shame.

[JimConlin]

... Your best bet here is to contact Robb for guidance.

Sadly, Robb is no longer with us.

[176inches]

Steve:
You can tape the patterns on the plywood and make marks with a small nail or awl at regular intervals. Then remove the paper, drive nails through the marks and draw the shape by bending a thin batten around the nails (on the concave side). Or you can use large size carbon paper sheets (don't know where to find them though).

Also, please don't take things personally around here...

[Breakaway]

Steve

The guys who replied are in the top echelon of experience on this forum. They are just being straight.

That said, get a book on "lofting" boats and take it from there.Lofting is the process of drawing the plans out full size prior to building.

Kevin

[176inches]

If you don't have full-scale plans, you'll have to use coordinates (offsets) if available, and if not, you can calculate them by scaling up from the drawing. Pick enough points, measure X and Y distances from the centerline and baseline in the small-scale drawing, scale up to full size, then mark them on the plywood and use the nail-and-batten method I described above. I've been using these methods for a while now. Any plan of any size can be transferred to ply with a bit of patience.

[mick allen]

The likely reason you are getting a few short responses needs some reading between the lines. The boat you wish to convert to SOF implies the use of an outboard motor. SOF's with an outboard are not that frequently built, so the main issues are not that well refined and developed. (tho' some big umiaks and currachs have mounted outboards) And so there are 2 big concerns: the second of which is that the transom/stringer/hull interface needs to be strong enough to take the weight, force and vibration of the motor which may tear your boat apart, and the first of which is that if a problem does arise there is so little inherent floatation that it will go straight to the bottom, fast. Plus being a newbie you (me too, probably) possibly haven't developed the judgement to react to these impending dangers.

However the simple transference of lines can be done by the many ways mentioned: the simple way is to send the half sections to a print shop and get multiple copies. The first issue is offsetting them for the stringer thickness. If you want to save a little labour, and as the forms drawings will be too large by the thickness of the stringers you will be using, get them reduced by proportions that will allow for the offset - this is not perfect, but if you can get differential proportioning it might be not bad. Others are sketching over the plans on tracing paper and spraygluing them down, pricking thru the plans by icepick or dress pattern rollers, offsetting by use of a parallel or arm drafter, 1:1 pantograph, carbon paper, etc, etc.

For structure, assume you'll use a heavier skin with adherence to the stringers, transom gussets to the stringers (maybe doubled toward the transom), and more stringers than usual. I think Robert Morris's book has a transomed boat build that could be used for some reference.

At first, use a small motor, alone, with personal and vessel floatation to develop that judgement. Be humble enough to make changes if apparent.

[TerryLL]

Sadly, Robb is no longer with us.

Sorry, I did not know.

[TerryLL]

If anyone has postive or encouraging comments please do pass them along.

Come on guys, it was a simple question, not a challenge to your knowledge, experience or grand wisdom.
If you don't have the answer just say so, negative comments do nothing to encourage others to add to this forum.
And as often happens only a few remain and this is the kind of reception they give newbies.

Perhaps I've misunderstood the nature, spirit or intend of a forum such as this. What a shame.

Steve,

Jim's comment and mine were intended to help you avoid stepping into a tar pit. Unfortunately, when a new builder is advised to reconsider, to rethink, to get professional advice before proceeding, they almost always react as you have. Advice on this forum comes in many forms, and the advice to not walk into the tar pit is seldom heeded.

[JimConlin]

Maybe I've lost count, but I think that we have a couple of tar pit experiences unfolding daily.

[176inches]

Steve,

Jim's comment and mine were intended to help you avoid stepping into a tar pit. Unfortunately, when a new builder is advised to reconsider, to rethink, to get professional advice before proceeding, they almost always react as you have. Advice on this forum comes in many forms, and the advice to not walk into the tar pit is seldom heeded.

I can definitely recognize the situation. Of course you are right. But some new builders (or builders using a new method) just prefer to make their own mistakes and learn from them. I did it myself to some extent (after a lot of research and before I discovered this and other forums). Learning from your mistakes can be pretty expensive, but I guess I've been lucky so far.

[Sayla]

Hello

looking for guidance
I have a set of plans for the Robb White Sportboat. My intention is to make a skin on frame version of this boat.
Being a newbie I'm not sure what is the simplest way to transfer the frame lines (boat shape) from the plans onto plywood in order to draw out the frames I'll need.

I realize I could have multiple copies of the plans printed and then just cut out but I don't have access to a large printer and I'd like to learn how to do this anyway.

Ideally I would like to end up with full sized rib/frame outlines that can be transfers onto plywood.

I realize this is pretty basic for experienced buidlers and likely has been discussed before, so just need to be guided to specific threads or videos would be great.

thanks
Steve

Carbon paper as mentioned is quite good - make sure you choose a smooth faced plywood - some plywood faces are rather rough and frustratingly muck up your finer line drawing of the lines - establish centreline and the common waterline or building jig line that is perpendicular, on all the plywood that you intend to use - if you aren't cutting the plywood per se, but just using it for line transfer, you may prefer a white board type particleboard (clearer lines). My personal preference is to digitize everything. i.e. lay a grid over the lines, and then measure, re-curve them, and store them in a cad file - fair bit of work for someone not used to cad - if you're not used to it, don't do it (use the carbon paper). Another method I have used is to get a pad full of tracing paper, clear tape some together (size as necessary) to make a bigger piece and trace the lines off the plans to transfer them.

If you have a more detailed question or other question, just ask.

sayla

[JimConlin]

It's hard not to sound nasty when some new soul turns up here and announces that he wants to build a cold-molded Japanese tub boat or a glued lapstrake Tahiti ketch.

Their questions don't have simple answers, so perhaps the best counsel is to refer him to the written word. For most of the common construction methods, there are good well-written how-to books.
For glued lap, the John Brooks, Iain Oughtred and Tom Hill books are excellent,
for strip composite and cold molding, the Ted Moores and Nick Schade books plus the Gougeon book,
for carvel plank, the Chappelle, Roessell, Bud McIntosh books
and the Dave Gerr 'Strength' book for all types.
I've left out many good ones, just because I don't (yet) have them, bit i wonder if the best way to answer a query like this is to send the inquirer off to read the book(s) for his enamored construction method.
What else should be on the book list? I don't have a good one for SOF.

Sorry if this sounds pompous,
Jim

[TerryLL]

... But some new builders (or builders using a new method) just prefer to make their own mistakes and learn from them....

Yup.
I'd be surprised if there are many experienced builders here who don't have a screw-up or two under their belt. I sure do.

I sometimes wonder what's the best approach when you see someone racing toward the cliff. Is it better to wave the red flag and get them to turn aside, or let them face-plant at the bottom? Certainly, the face-plant approach is the better teacher.

[sdenault]

I purchased the plans from Joy White (Robb's wife) both she and her sons encouraged me asked me to let them know how my SOF version of the Sport Boat turns out.

Just about any boat can by made using the SOF concept and techique; its a perfect medium for someone who wants to build ecomomically and still gain some of the qualities, at least the shape, of a boat. It reduces the need for a big well tooled shop and brings boat building back to its most basic origins.

Steve

[sdenault]

I do understand the lofting process but what I was trying to find out was are there any newer, perhaps non traditional, out of the box, ways of moving the plan line (boat shape) onto plywood to make my frames for this SOF type version of the Sport Boat.

Regarding the old salts, I'm not a youngster either but in my life I've found that true wisdom comes when someone with a good deal of practical experience has the wisdom and ability to respond to any question with patience and understand. All the wisdom in the world is of no value unless it can be transfered, here in lies one of histories Generation Gap challenges. Too often wisdom gained is withheld, horded or worse uncommunicated in a suitable manner to transfer knowledge forward.


S

[wizbang 13]

Ya takes half inch roofing nails and ya grinds the head into triangles with sharp points.
ya lays them triangle thingys down on the loftin lines and puts yer plywood down on em.
Nows the fun part, when ya walks around on the ply wood, then pick up the plywood with the former roofin nails stuck in.
then ya rips a skinny batten or 3 , layz em against the nails and foller the batten with a pen.
loves me some simple!

[sdenault]

Mick
Some very good points thank you. I will definitely take these to heart and build accordingly, especially the danger of this boat breaking. Also the intended use is small inland lakes and rivers.

The method of SOF I will use is close to Dave Gentry's boats. In my case I will be increasing the number of frames between seats and stern area. This should provide more floor board support and a stronger transom. Plus as you suggest increase the number of stringers. I will also use plywoof for the transom. Plus to hold it all together and toughen it up I plan to epoxy the 8-12 oz fabric skin.

I'm not looking for speed of any kind and intend to just use an electric motor to assist in the paddling and or for trolling.

I just finished a small punt/joh boat (9' x 3") and seems to have created a very strong and very light version.

What do you think of these precaution with regard to holding it together?
Steve

[sdenault]

Sayla
thanks, I'll try the tracing paper method, might be the most practical way for me in this situation.

My goal is to get one side of mold shape (one side of each, from the center line) off the plan onto a piece of plywood. This line will become the extern Frame line, together all the frames will allow me to duplicate the shape of this Sport Boat using the SOF building technique. I will make additional frames to support flooring where standing or cargo might be placed.

Steve

[sdenault]

Wizbang
I always enjoy it when someone takes something that everyone agrees is terribly complex and turns it into one of those 'smack my own forehead; holy **** I should have thought of that' moments. Simplicity and need have always been the mother of invention. Thank you

One of the things I really like about Dave Gentrys way of building SOF is that it is very forgiving and anciently intuitive. Of course it is best to try to stick to some general and basic hull building principles but I suspect that 3000 years ago boat building was more an issue of available tools and materials, especially in the far north, hence the orginal development of this frame skeleton with stretched skin method.

The bonus for us today is composite and other hi tech materials, that can in some instances replace heavy, thick lumber and other materials.

From my perspective part of the challenge and excitement comes from trying to overcome traditional and often sound logical practices with innovative solutions. But alas after doing so you eventually find is all been done before and we have come full circle back to what some guy a few thousand years ago did when he had to find a way to get out on the water to catch fish or transport game back home. That kind of survival need often is true the mother of invention and innovation.
Steve

[wizbang 13]

transfer a few "strike up marks" from the grid, onto the side of the ply, when it is on the floor, to be sure it is aligned with "square"

[CundysHarbor]

My favorite method of transferring full size section drawings to plywood is to use large carbon paper (avail. from Glen L) and a vibratory marker ($10 on line). I make a dot every half inch or so, closer in bendy places, and cut to the dots. Make the 1/4 inch cheapo plywood curve as carefully as you can and use it as a template for routing your molds.
Dave

[sdenault]

Another good one thank you.
I like the idea of using the plywood to make permanent templates; then I can do just one side of the center line, then flip the plywood to do the other side. Plus if I like the end boat I can make another and try different materials to lighten and strengthen the boat until I get something that will hold together in tough conditions or at least easily manage a small outboard.

cheers
Steve

[Greg Nolan]

Their questions don't have simple answers, so perhaps the best counsel is to refer him to the written word. For most of the common construction methods, there are good well-written how-to books.

* * *

What else should be on the book list? I don't have a good one for SOF.

Jim

Robert Morris's "Building Skin-on-Frame Boats" is extremely good, but out of print and used copies are usually not available at a reasonable cost. Your library might have it, or be able to get it for you.

[mcdenny]

A sewing supply store will sell a tracing wheel which looks like a little gear with sharp teeth.



Lay the paper over your wood and run the wheel around the outline. The teeth will pierce the paper and give you a faint but usable dotted line on the wood. The suggestions to use an awl to make prick marks through the paper into the wood is a variant of this same idea. If you are careful with the wheel you don't need to draw pencil lines, you can cut to the dotted marks. The only negative is it's pretty hard on the plans as it makes a perforated line everywhere you trace.

I personally use expensive but stable tracing paper (mylar) and an awl but the tracing wheel or carbon paper tricks work fine.

I tried wizbang's "nails laying on their side" method once but half the nails moved when I'd try to put the pattern wood on the lofted surface. It's is meant for transferring a shape drawn on wood (not paper) to another piece of wood.

PS: Don't take umbrage at the "don't do it" advice. You are proposing a very significant change in construction method and hence the boat's structural integrity. If you get this wrong and happen to be a 'hold my beer and watch this' test pilot in cold water you aren't just talking a couple of wasted gallons of epoxy, you could kill yourself.

I think you have an interesting idea that could work well. If it were me I'd add triangular gussets to tie the transom to the keel and stringers and really give the hull a workout in waist deep warm water. There are a couple of experienced SOF builders around here and maybe they can give you some specific advice about beefing up the hull to take an outboard.

[mick allen]

Your building and motor approach sounds reasonable to me. Just be careful about floatation.

As far as a non-traditional line tracing approach, take a pic of your linesplans and project them onto yr ply and trace over the projected image.
But I think that if you spend a little time on setup of a nice flat surface and can obtain a few yardstick size and quality pces of wood, the previously mentioned 1:1 pantograph just might be do the job and be fun as well.

[Jay Greer]

When I was in my teens and had just gotten a job at a boat shop that belonged to a friend of my father my first jobs were relegated to operating a push broom, fox tail and dust pan. I really wanted to start doing real boat building but, the seasoned builders had an air of mystery about them and rarely imparted much information about their trade. I had to learn by osmosis, observation and stealing their information. Here, on this forum, exists an immense amount of accumlated knowledge that is available just for the asking. Some of it is simple and some is complex. But everyone is here to share what they know or think they know. This is a good thing for us all as it keeps the knowledge of wooden boat building alive!

So here the question of how to transfer "full size frame drawings" is being asked. My question here is are these drawings of sections of the hull or are they of the actual frames. Are they to the inside of the skin that is to be laid over the frames. We would have called it "to the inside of plank" or are they to the inside of the frames themselves? If to the actual inside of skin it is of little consequence but to the inside of frame is another matter entirely. I am reminded here of a young man that once came to me with a simular question. He asked if I could help him solve some fairing problems with his boat he was starting to plank. I had asked to see his lofting work as things were really out of kilter and fair. He informed me that he didn't want to deal with that phase of the work as he had wanted to start building right away and just worked directly on the wood without lofting. Nothing was fair and he had reversed the stem and stern posts on the Block Islander he was building. The boat never was right! So here my advise is to take some time to understand lofting. One of the easiest explanations on the subject can be found in one of the works of L. Francis Herreshoff, "The Common Sense of Yacht Design". This is the same avise that was given to me, many years ago, by one of the workers who did lofting at the shop where I first worked. Though written over sixty years ago, the language is simple and to the point. Above all, it is easily understood and takes the mystery out of the art of lofting. I highly reccomend this work to anyone who is interested in gaining insite into boat design and construction.
Incidently the way I still transfer lines from the loft floor is to lay box nails down on the lines to be transfered so that their heads are on the line in question and tap the head head edges in lightly with a hammer, lay the pattern stock over it and walk on the pattern stock. This transfers the edges of the heads onto the pattern material. Then it is a simple matter to spring a batten around the marks and draw the line.
Again, I will firmly state here that I don't know anything about wooden boats!
Jay

[wizbang 13]

quote, "I still transfer lines from the loft floor is to lay box nails down on the lines to be transfered so that their heads are on the line in question and tap the head head edges in lightly with a hammer, lay the pattern stock over it and walk on the pattern stock. This transfers the edges of the heads onto the pattern material. Then it is a simple matter to spring a batten around the marks and draw the line."
post 21, grasshopper.

[Bob Cleek]

Ya know, everybody's gotta do the learning curve thing. Like Jay, when I started out in this game there was a hell of a lot less available in print about actually building boats properly. The tradesmen who had learned their craft kept it to themselves because their skill and experience was the product they sold to earn their daily bread and they had acquired it at no small expense. Nowdays, perhaps because there are so many fewer boatwrights who actually earn a full time living and so many fewer boats being built, the craft is far less arcane. There are any number of books, some great and some pure horse****e, which explain how it is done. That said, those who have learned some of the skills needed to maintain and build decent boats still share the pride of having learned those skills with some effort. It shouldn't be any surprise to somebody who just fell off the pumpkin wagon that they are told directly that they are going about it the wrong way when indeed they are. Anybody who aspires to build a SOF boat to raw lines drawn for any other construction method and asks how to pick up lines obviously lacks the breadth of knowledge necessary to even begin to expect any success in the endeavor. That's not intended as an insult, but rather is simply a statement of fact. At this point, how to pick up the lines is the least of the techniques one must learn. Maybe it wasn't the desire to keep secret the tricks of the trade for the purpose of ensuring job security that motivated the old time boatwrights at all. Maybe they were reluctant to answer questions only because they were sick of answering questions and getting the reaction we see here in this thread.

[TerryLL]

Well said Mr. Cleek.
Like you my background in boatbuilding spans a few years, having been bitten by the bug in the 60s, completing my first solo build in '78, and several since. After a life lived in boats, and in boat yards, I think I have a fair bit of experience to share. But lately I'm beginning to think what's the point? I am indeed very tired of offering advice to the new folks here only to be roundly criticized when the advice I offer is not the advice they want to hear. I'm thinking that the best approach may well be to let the crowd on 1-post wonders get their advice from all the other 1-post wonders.

[mick allen]

Well - I sit down to hopefully read some continuing discussion about this subject only to find that senior and established figures in this boat world regard my (and other similar) responses with distain and ‘sick’ness and regard my limited input with derision and name calling . . . .

Really guys, contribute or take a breather.

**

Anyway,
A quick look at robbwhite.com shows the sport boat as being transomed canoe shaped, strip built, and light. This infers 1) that the plans include closely spaced coordinated forms, 2) and that the drawn forms are to the inside of the stripping - which is thin.

And this means that lofting concerns are not relevant, and that so called ‘plank’ thickness is also essentially irrelevant for the derivation of a skin facsimile for this boat.

But as the future skin location will be generated from the outside of stringers that are supported on ribs or frames (not positive yet if you’re using multi-ribs or spaced frames), some (very) initial questions come to mind if one is to make the SOF more ‘fact’ than ‘simile’:

• 1)Should the outside face of the stringers be flush with the outside face of the designed stripper surface?
• 2)Should the skin’s peaks and valleys average out the stripper outside surface. Or does it matter really?
• 3)Can a simple dimensional offset from the building form drawing locate an appropriate stringer location to average the desired surface?
• 4)How many stringers will it take to acceptably respond to the rounded hull shape and tumblehome of the original?
• 5)How many stringers (if any) should be further dedicated to attempting to duplicate the reputed performance of the sport boat? Ie Is there be a wish for it to plane?
• 6)What are the important structural stringers/members for the motor loading? And how should they be attached?
• 7)And if frames are used, what logical concerns generates their location?
• 8)As it is so simple to derive, can dimensionally offset forms be used for setup instead of frames so that the multi stringer locations can be readily aesthetically adjusted while Robb White's shape is maintained - and then notched frames be fitted to maintain that aesthetic?

[Sayla]

Sayla
thanks, I'll try the tracing paper method, might be the most practical way for me in this situation.

My goal is to get one side of mold shape (one side of each, from the center line) off the plan onto a piece of plywood. This line will become the extern Frame line, together all the frames will allow me to duplicate the shape of this Sport Boat using the SOF building technique. I will make additional frames to support flooring where standing or cargo might be placed.

Steve

It sounds like you're going to build to what is called "outside the lines" (i.e. bigger - the skin/planking being outside the intended size), or are the lines specified as external frame?

I did this boat's molds with A3 pieces of tracing paper (bought a pad) stuck together with clear tape, cut along the section curve lines to get a half section, and transferred that onto plywood (and flipped it) for stations, and the section lines were specifically provided as "inside planking". (I still have them rolled up and could re-use them, like mylar)



sayla

[Tim Marchetti]

Looks like you have plenty of answers to your original question. Good luck with the build. I look forward to seeing it come together.

[Tom Robb]

If you xerox your plans to get copies of the molds' shapes, the copy will probably not be to scale - copy errors.
The accuracy of a tracing from the paper plan will will depend upon how much humidity changes have distorted the paper.
If neither of the above concern you, the boat you build may resemble the plan boat or it may not.
If not, you've become the designer of record and any success or failure of the boat is your responsibility.
If it's to be failure and you or your heirs decide a lawsuit against Robb White et al (no relation) is a good idea and I'm on the jury, you'll lose.

As stated above, the answers you don't want were from experienced people.
This sort of thing happens here with depressing regularity. Please know that the advice was/is meant to be in your best interests. The suggested readings ought to be especially useful.

Be that as it may, good luck and try it out in shallow enough to stand in warm water.
If it works you can come back and say, "I told ya so!"