Rare complete ship's curves set on eBay

[Bob Cleek]

Somebody's selling an extremely rare complete cased set of Keuffel and Esser "Copenhagen" ship's curves on eBay. (Not me. I've no dog in the fight. I already have a set.) I thought some MSW forumites might be interested in seeing what a set looks like.

 

Similar to "French curves," these "mathematically shaped" curves are used in the same manner as "French curves" by naval architects to draw fair curves when drawing ships' lines. Sometimes called "Copenhagen curves," when used in conjunction with one another to join points laid out on the drafting board, they will permit drawing a fair curve of any shape whatsoever.  Dealt a death blow by CAD, like a lot of essential manual drafting instruments, they are no longer made and are unobtainable on the retail market. The perfect gift for the scratch-builder who has (almost) everything! A steal at a "buy it now" price of only $600! (Insert "sarcasm" emoji here.)  https://www.ebay.com/itm/Lot-of-56-Keuffel-Esser-Co-1864-Ship-French-Drafting-Curves-With-Box/183690539257?hash=item2ac4cf30f9:g:9tcAAOSwGFZcae~q

 

Thirty-one "watchers" and nobody's bought it yet. It'll be interesting to see what it ultimately brings when the seller wises up (or gets lucky.) It's worth watching (click on the "watch" feature to track it) to see what happens. I'd have guessed it would have been priced between two and three hundred, at most. The collectors can get crazy sometimes, though. I didn't pay anywhere near that for my used set, but that was years ago before manual drafting instruments became hard to find and highly collectible. There was a brief moment in time right after everybody went over to CAD and had no interest in manual instruments when even the finest manual instruments in mint condition could be bought for peanuts. Like vinyl records, the advantages of manual instruments have been rediscovered and are now highly prized by collectors and users alike.

 

 

 

Edited February 24, 2020 by Bob Cleek

[druxey]

Nice to see a complete set, but I think $600 is overpriced.  Either that or I'm sitting on a gold mine with my own complete set!

[Bob Cleek]

14 minutes ago, druxey said:

Nice to see a complete set, but I think $600 is overpriced.  Either that or I'm sitting on a gold mine with my own complete set!

You and me both! I've also got complete sets of K&E French curves, engineers' curves, and "railroad" and "highway" radius curves. I've got a fair number of "doubles" to the ship's and French curve sets. I had to buy "odds and ends" in lots before I got all of them. I built them up over a period of three years or so when the stuff started appearing on eBay and before collecting it got really popular. I built quite a collection of top-of-the-line K&E Paragon drafting instruments. It started when I first bought a K&E Paragon planimeter to calculate displacement and I went downhill from there.  I finally "admitted I had a problem" and "got into rehab" when the prices started climbing exponentially. 

 

Edited February 24, 2020 by Bob Cleek

[druxey]

I feel your pain, Bob. Current prices certainly make for attitude adjustment. I also have a lovely pearwood set of radius curves 3" to 200". Those earlier, heady days of eBay, when bargains could still be had! I still occasionally look and whimper softly.

[druxey]

Well, YT, you must have a very steady hand! I find the long curves very useful for laying out spiled planks.

[Justin P.]

13 hours ago, druxey said:

Nice to see a complete set, but I think $600 is overpriced.  Either that or I'm sitting on a gold mine with my own complete set!

Are they made of crystal?   

[Bob Cleek]

4 hours ago, Justin P. said:

Are they made of crystal?   

You'd think so, but actually they are made of "Luxite," K&E's trade name, which is apparently a type of plexiglass plastic material. The early curves were made of boxwood, ebony, and pearwood. In the mid-1800's, some were made of hard rubber.

 

They were essential to drafting plans in naval architecture, aviation, and automobile design before CAD became available and, even now, only the most sophisticated (and expensive) CAD programs are capable of approaching what Copenhagen curves can do, often much easier and faster than CAD, as well. CAD caused a drop in demand for them below what was necessary to make producing them profitable. Demand for mechanical drafting and surveying instruments dropped dramatically as the industry "went digital" and K&E filed for bankruptcy in 1982. The trade name was purchased by others, but nothing was done with it and that was the end of the high-end drafting instrument industry in the U.S, at least. The European manufacturers lasted only a few years beyond that. There's always been a demand for manual drafting instruments, and when the sources dried up, the value of existing instruments eventually skyrocketed when collectors entered the used instrument market. Curves sets, first marketed by Keuffel and Esser right after the Civil War, were never inexpensive. While they may not appear so, they are precision instruments that must exactly replicate mathematically defined fair curves. One fellow attempted recently to produce Copenhagen curves as a "Go Fund Me" business, but failed to get enough financial support to pay for the tooling to commence production. Complete sets are very difficult to find these days and people do pay a lot of money for the few sets that come up for auction now and again. A CAD program that can come close to what can be done manually with curves will set you back a lot more than what the curves are going for now and likely require a steep learning curve to master.

Edited February 24, 2020 by Bob Cleek

[DWSmith]

What constitutes a complete set?  I have a set in the wooden box but am not sure if it is complete.  If I'm missing any can they be replaced? Thanks in advance.

Dana

 

Edited February 25, 2020 by DWSmith
additional information

[DWSmith]

The set I have has 54 pieces in it but some are labeled greater than 100.  I also have the 7 piece ships curve set by C-Thru and a few french curves.  Was there a method of determining which curve to use or is it simply try and fit.  Thanks again.

[druxey]

Here is the 'official' complete set:

[Bob Cleek]

3 hours ago, druxey said:

Here is the 'official' complete set:

Beat me to it! That's a copy of the Keuffel and Esser catalog page showing the Copenhagen curve set. There are 56 curves in the standard "Copenhagen curve" set. Check out the old K&E catalogs on line and find the details. Here's one:  http://archive.org/stream/pricelistcatalog00keuf#page/231/mode/1up   They were sold as sets, but I believe they could also be ordered individually. Each curve has a K&E part number on it. The famous British naval architect, Dixon Kemp, designed a set of ships' curves, as well in the late 1800's. Kemp's curves were sort of "egg" or "kidney-shaped" and nested inside of each other with three or four "rings" to a set. The sets, of identical shapes, came in two sizes. I've seen pictures of these in books, but have never seen them in the flesh. They were a British item and apparently never caught on in the rest of the world.

 

 

Edited February 25, 2020 by Bob Cleek

[Bob Cleek]

3 hours ago, DWSmith said:

The set I have has 54 pieces in it but some are labeled greater than 100.  I also have the 7 piece ships curve set by C-Thru and a few french curves.  Was there a method of determining which curve to use or is it simply try and fit.  Thanks again.

As mentioned, There are 56 curves in the standard Copenhagen curves set. There are many other types of curves, sometimes called "French" curves. These can be found in the old K&E catalogs, one of the more recent ones from the 1930's is found at http://archive.org/stream/pricelistcatalog00keuf#page/231/mode/1up  The curves begin at page 231. The Copenhagen curves are at page 234 and following.

 

The short answer is that, yes, you just have to "try and fit" to get the right curve. The method of use is illustrated below. A curve is defined by a series of "points" (dots) which would in the case of a ship's lines, come from the Table of Offsets, or from measurements from original plans, if one were copying those (usually when changing the scale of the drawing, generally using a pair of proportional dividers.) When the points are laid out, the curves are selected so that they coincide with as many points as possible. sometimes points will be out of position slightly and this indicates that the curve defined by the points is not fair, in which case, the curve will define the fair curve. The curve should "touch" at least three points and preferably more. A French curve is being used to draw the curve in the illustration below. The illustration is of the use of a single French curve. There is no rule against using multiple curves. They are designed to be used that way, such that if they touch at least three points in common, the two curves will define a fair curve when joined at such an overlap. It can be seen that in "A" below, the curve is touching points one through 4. The line would be drawn that far and then, in the illustration, another curve section of the French cure is used to draw points 3, 4, and 5, and in "C" has been manipulated again to draw from point 5 to point 6, and in "D" to draw between 6 and 7, in "E," using the inside of the curve, to draw from point 7 to point 9 and finally in "F" moving the curve again to draw the line from point 9 to point 11, thus drawing the shape intended with a fair curve. In each instance, the curve was moved to see if it fit a number of points. The "eyeballing" to fit the curve isn't as complicated as one might imagine, except in complex curves like the one illustrated below which required six segments to be drawn from six positionings of the curve. Working with lines drawings, it's not too difficult to find a curve, or collection of curves, to meet your needs.

 

 

 

 

When inking drawings, which in the old days was done with India ink and a "ruling pen," the draftsmen would tape coins or washers to the face of the curves being used so that the edge of the curve was raised slightly above the paper or drafting linen. This space prevented ink "wicking" beneath the edge of the curve and ruining the drawing.  Curved lines were drawn using curves with a "curve pen," which had an offset nib which swiveled on a rod running through the center of the handle. This feature kept the pen point always "trailing" and oriented parallel to the edge being used. In this fashion, the width of the curved line would always be the same, being the distance set by adjusting the space between the nibs. The pen on the left in the picture below is a single point curve pen. The two middle pens pictured below are "railroad" curve pens which, by means of a double pointed head, will draw two curved lines simultaneously and as wide and as far apart as the user wishes to adjust them. All three curve pens can be used as regular ruling pens by tightening the knob at the end of their handles. This prevents the heads from swiveling when its tightened down. The third pen pictured is a drop point compass pen which is designed to ink very small circles. The needle point plunges down the center tube and the pen point rotates around the needle point on the tube. These were also called "rivet pens," because they were originally designed and used for drawing rivets in iron construction drawings. 

 

 

 

Edited February 25, 2020 by Bob Cleek

[wefalck]

Any idea, why they are called 'Copenhagen' curves ? As they are also called Burmester-Curves in Gemany, I first thought this had to do with the Copenhagen yard of Burmester & Waine, but it actually refers to the mathematician Ludwig Burmester (1840-1927), who seems to have invented at least one type of these templates based on third order splines. In Germany they are also called French Curves, which may reflect the fact that they were also used in the fashion industry to create continuous flowing curves when designing patterns.

 

Not sure, whether the mathematical rules for each of the individual templates have been preserved. Otherwise one could scan them from a catalogue or a set of originals, clean the files up and produce from them digitised versions as a basis for a laser-cutting project.

 

I bought a classical 3-piece set in acrylics some forty years ago, which has a recessed edge on each side to be used with ink drawing pens. I inherited another simple set in pear(?) wood inherited from my father. At that time I think people glued cardboard bits onto the sides to raise the templates off the paper for drawing with the ink pens.

 

When drawing lines plans, I found the 3-piece set mostly sufficient, but even the long template too curved for spars and similar. It also depends on the absolute size of your drawings, of course.

[Bob Blarney]

Hmm, make a computer scan of the  complete set, and then a person with a CNC can make a set for you lickety split, in any size you want.

By the way, I did a very fine sanding on one side of an inexpensive office supply set.  This allows me to mark spots along the edge with a pencil if I need to duplicate a curve later or flip it over to trace a matching chiral curve.  The pencil mark can be removed with an ordinary eraser.
 

[Bob Cleek]

25 minutes ago, Bob Blarney said:

Hmm, make a computer scan of the  complete set, and then a person with a CNC can make a set for you lickety split, in any size you want.

By the way, I did a very fine sanding on one side of an inexpensive office supply set.  This allows me to mark spots along the edge with a pencil if I need to duplicate a curve later or flip it over to trace a matching chiral curve.  The pencil mark can be removed with an ordinary eraser.
 

I do the same with mine by putting a piece of masking tape or Post-it note on the top face of the curve and marking that. As for cutting them on a CNC machine, the guy who had the "Kickstarter" site to do exactly that couldn't generate enough interest to get tooled up and into production. I don't know why beyond that, though. (See: 

)

Edited February 25, 2020 by Bob Cleek

[Bob Blarney]

16 minutes ago, Bob Cleek said:

I do the same with mine by putting a piece of masking tape or Post-it note on the top face of the curve and marking that. As for cutting them on a CNC machine, the guy who had the "Go Fund Me" site to do exactly that couldn't generate enough interest to get tooled up and into production. I don't know why beyond that, though.

Maybe I'll take cruise over to i3Detroit.org.  It's a art/craft/maker community with just about every tool you could think of, and $50/month gets 24/7 access to it all.  But the real value is in the people who participate - every kind of artists, machinists, engineers, designers, you name it.  Detroit is still a technological powerhouse

[Bob Cleek]

Go for it!

[Bob Cleek]

5 minutes ago, Bob Blarney said:

Maybe I'll take cruise over to i3Detroit.org.  It's a art/craft/maker community with just about every tool you could think of, and $50/month gets 24/7 access to it all.  But the real value is in the people who participate - every kind of artists, machinists, engineers, designers, you name it.  Detroit is still a technological powerhouse

Go for it. From what I gather, though, the machine time it takes to make the cuts costs more than they can be sold for.

[Bob Blarney]

1 hour ago, Bob Cleek said:

Go for it. From what I gather, though, the machine time it takes to make the cuts costs more than they can be sold for.

Ah, but there are people who teach about how to use it.  Here's the equipment list

https://www.i3detroit.org/wiki/Category:Equipment

[Bob Cleek]

13 hours ago, wefalck said:

Any idea, why they are called 'Copenhagen' curves ? As they are also called Burmester-Curves in Gemany,

I've never found any citation to academic authority answering that question. I do have a theory, though.

 

There are different types of "curves." Specifically, there are ship's curves, of which the two most common sets are "Copenhagen curves" and "Dixon Kemp's curves." There are "irregular curves," also called "engineering curves" or "Burmester's curves." And there are "French curves."  (I  don't know why they were called "French curves."  The British always seemed to add a place-of-origin adjective to anything from elsewhere. Perhaps it was intended as an insult, much as they called condoms "French letters" and syphilis "the French disease."

 

Burmester designed the now-classic set of 28 "irregular curves" bearing his name in 1904, at least 150 years after the differently-shaped "ships' curves" came into common use. "French curves" were also in existence long before Burmester designed his curves.  Of Burmester's set of 28 "irregular curves," three are the most commonly encountered today and are still in production and sold in art and stationary stores, often incorrectly labeled as "French curves." Burmester's curves are mathematically defined curves designed to solve mechanism solutions for full link rotatibility, compactness criteria, and feasible transmission angles in multiple position linkage mechanisms. (Or so says one research paper.)  Each curve is defined by algebraic equations. Beyond that, it's way above my pay grade!   In summary, Burmester curves can be used to draw fair curves in the same way as French curves or ships' curves, but they were specifically designed for use in mechanical engineering to design linkage systems.

 

As far back as we know, patterns and templates were used in shipbuilding by the Romans, who built fleets of sister ships from standardized full-size lofting patterns. The use of drafting curves in naval architectural drafting appeared in the Eighteenth Century contemporaneously with the practice of drawn ships plans demanded by the development of  scientific approaches and the use of theoretical models in naval architecture, which previously had been an exercise in trial and error and "monkey see, monkey do."  In Western Europe, at least, the "Father of Scientific Naval Architecture" was Fredrik Henrik af Chapman of Architectura Navalis Mercatoria (1768) fame. Chapman devised the "parabola method" of ship construction and design, which identified the relationships between certain fair curves and their effects on speed, stability, and the displacement of ships. (Increased stability was a huge advance.  More displacement and stability meant more guns could be mounted and higher above the waterline, which meant they could open the gun ports in heavier weather.) It may be presumed that as Chapman's scientific curves were adopted as part of the naval architect's lexicon, curve templates for drawing them were created. Chapman's curves were, like Burmester's, defined by algebraic equations, but for different purposes.

 

I suspect we have Chapman to thank for the English term "Copenhagen" curves. Chapman's theories certainly occasioned their invention even if that was by someone else. Chapman was an interesting fellow in many ways. He was a self-made shipwright who virtually invented scientific naval architecture, going back to school to learn the cutting edge mathematics of his time. In the mid-1700's, as most know, Western Europe was in political flux and wars were commonplace. Chapman was British, but born in Stockholm, Sweden, to a British father. He traveled around, studying the shipbuilding practices of the various nations' navies. At one point, that landed him under house arrest in Britain, which considered him a bit too cozy with the French, and, right after that, tried to hire him to design ships for the Admiralty. He almost did, but then took a similar job with the Swedish. In those days, his ability as a warship designer made him the Werner von Braun of his day, with nations so eager to secure his technical expertise that his prior political affiliations were ignored. But Copenhagen is in Denmark, not Sweden, and Chapman worked in Stockholm. That is so, but from 1397 to 1523, all of Scandinavia had been united under the flag of the "Kalmar Union" and Norway continued to be united with Denmark between 1524 and 1824. Copenhagen was the capitol of the Kalmar Union and the Norwegian-Danish Union. It's reasonable to conclude that Chapman's technology was common to all the Scandinavian nations and, from the perspective of  England, anything coming from Scandinavia might be called "from Copenhagen" in much the same way the world refers to "Washington," "London," or "Moscow" to reference the U.S., Britain, or Russia. And so, they became "Copenhagen curves" because that's where the English thought they came from. They already had "Stockholm tar," so maybe they thought they'd spread the credit around and call them "Copenhagen curves."

 

At least that's my best guess. Can anybody shed any more light on the subject?

Edited February 26, 2020 by Bob Cleek

[Bob Cleek]

22 hours ago, DWSmith said:

What constitutes a complete set?  I have a set in the wooden box but am not sure if it is complete.  If I'm missing any can they be replaced? Thanks in advance.

Dana

 

Well, I'll be... I just came across a German art supply house that is selling about forty or so of the original numbered Copenhagen curves. https://www.mp-artware.de/shop/en/Templates/Ship-curves/  These must have come back on the market fairly recently. I'll bet there's money to be made in the short term buying up a bunch of them and selling them as near-complete sets on eBay!  

 

As you can see from the above posts, or by going on line and googling a better chart of them, you can see what you might be missing. 

[DWSmith]

20 hours ago, Bob Cleek said:

Beat me to it! That's a copy of the Keuffel and Esser catalog page showing the Copenhagen curve set. There are 56 curves in the standard "Copenhagen curve" set. Check out the old K&E catalogs on line and find the details. Here's one:  http://archive.org/stream/pricelistcatalog00keuf#page/231/mode/1up   They were sold as sets, but I believe they could also be ordered individually. Each curve has a K&E part number on it. The famous British naval architect, Dixon Kemp, designed a set of ships' curves, as well in the late 1800's. Kemp's curves were sort of "egg" or "kidney-shaped" and nested inside of each other with three or four "rings" to a set. The sets, of identical shapes, came in two sizes. I've seen pictures of these in books, but have never seen them in the flesh. They were a British item and apparently never caught on in the rest of the world.

 

 

Tried to order the curve(s) I'm missing and it appears USA is not a country they do business with.  At least when I tried to fill out the form - USA, United States, etc was not a country in the list.

[Bob Cleek]

6 hours ago, Y.T. said:

So how all this first evolve? My understanding is original shipbuilders were making their ships without drawings. When pretty good ship hulls were created it appeared it would be beneficial to have some drawings made so good stuff can be recreated. Were not these curves made just for draftsman to make sure drawings are good?

Drawn ship plans came rather late in the game at the end of the Seventeenth Century. Before then, vessels were often built by "rule of thumb." From experience, the size of the parts were described in relation to each other. A mast would be as long as the ship was long on deck. The mast would be placed in the middle of the keel's length. A bowsprit would be the length of the distance from the mast to the stem, and so on. The shape of a hull would be defined by a midship mold and perhaps a couple of molds half way between midships and the stem and stern. These molds would be saved and kept as patterns for later builds, or modified in shape a bit, if they thought that would improve the ship. If a ship was "tender," they'd build the next one with a bit shorter mast or with a bit wider beam, or both, and so on. Once the molds were set up on the keel, temporary battens would be bent over the molds to define the shape of the hull and the framing made to fit the shape defined by those battens. 

 

During the "Age of Enlightenment," when scientific analysis began, they discovered there were rules of physics that determined the properties of a sailing vessel's performance and they reduced these rules to mathematical equations. This made designing ships on paper possible and practical. They didn't have to build a whole ship to see how she sailed. They could actually calculate the displacement of a ship, its center of effort, metacentric height, center of effort and so on and mathematically calculate, for example, how large the area of the rudder should be, how much weight it could carry, and whether the hull could stand up to a given area of canvas. When they started drawing, they started developing specialized drawing tools to make that job easier.

 

Fair curves were originally and always continued to be drawn with battens and weights.

Some curves were too tight to easily be drawn with battens, though. Draftsmen always used templates to draw repetitive shapes. The "ships' curves" and other curves eventually evolved to represent mathematically defined curves when the interrelationship of different mathematically defined curves were discovered by mathematicians. The ships' curves as they ultimately came to be, were, of course, intended as an aid to drawing the plans, but not just as a matter of "neatness." Far more importantly, they were a matter of ensuring mathematical "fairness" in the development of the shapes that were being represented in the drafts. Using curves made it not only possible to draw neat lines, but to efficiently draw lines that were fair. 

Edited February 26, 2020 by Bob Cleek

[Shar]

Hi, I have a K + E set of Luxylite curves in a wooden box, very good condition, that I am looking to sell. Any advice on where to post?

 

[mtaylor]

19 hours ago, Shar said:

Hi, I have a K + E set of Luxylite curves in a wooden box, very good condition, that I am looking to sell. Any advice on where to post?

 

Here's the place but you'll need to have 25 posts first.  That keeps those out who just want to use us as Ebay.

https://modelshipworld.com/forum/41-traders-dealers-buying-or-selling-anything-discuss-new-products-and-ship-model-goodies-here-as-well/

[druxey]

Members of this forum would be interested, for sure ( I have had my own set for years.) Mark's advice will be helpful.

[Bob Cleek]

I'm sure somebody on the MSW forum would be thrilled to obtain a set of Copenhagen ship's curves. Don't let the 25 post requirement scare you off. The moderators may hate me for saying this, but all you have to do is take a look at the completed build logs and post "Beautiful!" twenty-four times!  (You've already done your first post here.) You'll enjoy the beautiful pictures, too, for sure!  

 

Like Druxey, I already have my set of K&E Copenhagen ships curves in a wooden box, together with another wooden boxed set of K&E "radius curves," sometimes called "railroad" or "highway" curves, these being two different measuring systems for fixed radius curves, one based on the distance of the curve across the segment and the other based on the chord across the segment. (The K&E radius curves are marked for both "highway" and "railroad" use.) I also have all the "French" and "Engineering" curves that were produced and sold by K&E. (Yes, I'm both a "user" and a "collector." "He who dies with the most tools wins!") I mention this because there are different types of drafting curve sets for different purposes. The one most sought after by ship modelers and naval architects, which has not been produced for some time in its complete form, is the "Copenhagen ship's curve" set. (There are other types of "ship's curves," as well, but not sold by K&E.) Thus, it will be important for you to note which boxed set of K&E curves you have.

 

There was a complete set of K&K Copenhagen ship's curves offered on US eBay which has just expired: VINTAGE DRAFTING WOOD TOOL BOX W/ COPENHAGEN SHIPS CURVES 50+ | eBay   This eBay listing will make it possible to identify the curves you have, if you are not certain already which type they are. If your set contains curves that are all regularly shaped segments of variously sized circles, it's the radius curve set, also useful for some modeling tasks (e.g. determining deck cambers) but the radius curve sets are more commonly seen than the now somewhat rare Copenhagen ship's curves sets, which are selling on the second hand market for much more money. (Yes, a full boxed set of Copenhagen ship's curves currently sell in the hundreds of dollars, but they have a history of very reliable appreciation in the marketplace.) Their shapes are mathematically generated so that when used as designed in conjunction with each other, perfectly fair curves of any shape can be drawn with them. If one needs to draw frame shapes and sheer curves from incomplete lines drawings or a table of offsets, these are the tools you need, short of a sophisticated CAD program and the skill to run it. (And using curves is much faster than CAD programming, too!) 

 

 

See the eBay listing for photos of all the variously shaped ship's curves.

 

This is the boxed set of radius curves:

 

RADIUS RAILROAD CURVES METRIC COMPLETE SET 55 PCS EXCELLENT L@@K!!!!!!!! | eBay

 

Pity those who aren't old enough to have taken drafting, or "mechanical drawing," in high school. It's really an essential skill for serious scratch-building ship models. CAD has replaced manual drafting in most industrial applications, but it's beyond me how anybody can really master CAD without understanding the basics of manual drafting. It seems sort of like learning to type without knowing how to spell, if not read! If anybody wonders how to use drafting curves, this YouTube video shows how: 

 

Drafting Tools 101 - Learn How to Use French Curves - Bing video

Edited August 30, 2021 by Bob Cleek

[Bob Cleek]

This could be somebody's lucky day!  US eBay has a complete set of Copenhagen curves by a company I've never seen before, but a curve is a curve. The listing ends today and there's only a couple of bids. It's at $51.00 with free shipping! If anybody wants a set of Copenhagen curves for a bargain basement price, this may be your chance. The short listing time probably means a lot of people haven't noticed it yet. Martin Copenhagen Drafting Curves | eBay

Edited September 2, 2021 by Bob Cleek

[nates]

Thank you for the insightful information on the various ship curves.  I have a set of Lyman Radius curves

Although they are not ship curves, I know they are highway curves and they are quite a few for sale on line.... I have searched the web, and the US patent office and have found nothing about their origin nor who designed them...let alone how one actually used them... I was hoping someone on this site might be able to tell me a bit more about them.

Any information would be most welcome...here is set similar to mine on worthpoint...

 

https://www.worthpoint.com/worthopedia/vintage-engineering-lyman-radius-

[Bob Cleek]

On 3/6/2022 at 2:20 PM, nates said:

Thank you for the insightful information on the various ship curves.  I have a set of Lyman Radius curves

Although they are not ship curves, I know they are highway curves and they are quite a few for sale on line.... I have searched the web, and the US patent office and have found nothing about their origin nor who designed them...let alone how one actually used them... I was hoping someone on this site might be able to tell me a bit more about them.

Any information would be most welcome...here is set similar to mine on worthpoint...

 

https://www.worthpoint.com/worthopedia/vintage-engineering-lyman-radius-

Those are "radius" or highway/railroad curves. They were primarily used by highway and railroad engineers to lay out fair curves of various radii when planning highways and railroads. They are, as marked, segments of circles with the radius indicated on the individual curve. Lyman's Radius curves are distinguished by the clever way they stacked up and stored, but are otherwise identical to any other make of radius curve. You use them by using the curve edge to draw a segment of a curve with a radius of the indicated length. They come in handy for large radii curves and eliminate the need for a long beam compass and the large drawing table required to accommodate, for example, a 48" radius beam compass. They are handy in ship modeling for determining deck and cabin top camber at various stations on a hull without doing a lot of math to adjust for the width of the deck at the various stations. You can just find the curve that matches the camber for one station (which is all that is given in most plans) and then fit it to all the other stations.  (Draw a line as wide as the deck at the subject station indicated in the plans, generally the widest at the deck or sheer line, and draw a perpendicular line as high as the camber height in the middle of the deck width line. Then, by trial, find a curve that touches the two ends of the deck line and the top of the camber height line and use that curve to lay out the deck camber at every station.) As a practical matter, the camber on larger vessels at smaller scales is so small as to be negligible, but if you are building smaller vessels at larger scales, such as yachts and small working craft, the  camber each deck frame is often a significant detail.