Bob Cleek

Yes. The triangular "architects'" and "engineers'" rules have grooves cut down the middle of each face. Their purpose was to hold a couple of purpose-designed spring clips that served as grips so the rule could be picked up and set down with the chosen scale always "face up." The spring clips could be set in the grooves so the scale face desired was instantly identifiable. I've only seen pictures of these spring clips in drafting manuals. They're scarce as hen's teeth these days, I suppose, but the grooves remain. As noted, the common spring binder clip serves as well.
 

Yes. The triangular "architects'" and "engineers'" rules have grooves cut down the middle of each face. Their purpose was to hold a couple of purpose-designed spring clips that served as grips so the rule could be picked up and set down with the chosen scale always "face up." The spring clips could be set in the grooves so the scale face desired was instantly identifiable. I've only seen pictures of these spring clips in drafting manuals. They're scarce as hen's teeth these days, I suppose, but the grooves remain. As noted, the common spring binder clip serves as well.
 

The best way to be sure is to spend the money to purchase rules from one of the recognized quality manufacturers. Accurate rules are intended for use with the desired distances taken up with a pair of good dividers. The divider points make accurate measuring easier as small distances can be seen on the rule's markings. Rules should be handled with care and not used as straightedges, especially not for cutting. 
 
A reliable top of the line brand is Starrett. Their instructional bulletin is a gold mine of knowledge on measuring in the shop:    tools-rules---bulletin-1211.pdf (starrett.com) . They have a separate catalog for rules: Precision Rules, Straight Edges & Parallels (starrett.com) Starrett's competition since forever is Brown and Sharpe. One of their six-inch pocket rules will run you around $23.00 at Walmart, but you'll know it's exactly six inches. Brown & Sharpe 599-313-603 Stainless Steel Stainless Rule, 6" Length - Walmart.com On the used market, another very high quality U.S. rule manufacturer to keep an eye out for is Theodore Alteneder & Sons of Philadelphia, which is no longer in business. Similar names from the past are Keuffel and Esser, Dieitzgen, Post, and Bowen.
 
Modeler's will find triangular architects' scales handy. These have six scales, two on each face of the three sides of the triangular-section rule. The scales permit picking up the scale distance directly from the rule without needing to convert measurements to scale each time you take up a measurement.
 

Top 10 Best Scale Ruler (topportalreview.com)
 
Once upon a time, the manual drafting instrument manufacturers made a wide range of scale rules for architects and engineers. (Another type were  "shrinkage rules" made for patternmakers, whose measurements had to take into account the shrinkage factors of various casting metals.) These rules weren't of the newer triangular pattern, but, rather, each flat rule had two scales, one on each edge. They were beautifully made of boxwood and came in cased sets. There are out there drifting around. If you ever see one for a price you can afford, grab it, because they aren't making these beauties anymore.
 

 
 
 
 
 
 

Having heard this specific admonition as well, I decided to finally look it up. It turns out that "ruler" as a measuring instrument is well attested to in the historical record. 
 
For example this line from the Wycliffe Bible (circa late 14th century): 
"He graueth diligently..bi þe kunnyng of his craft..licne it to an ymage of man, or to sum of beestis; it he comparisowne þurȝdrawinge with a rewler, & make þe colour of it with red & broun."
 
And in Early Modern English, from mathematician Robert Recorde's The pathway to knowledg, containing the first principles of geometrie (1551):
"More easyly..may you fynde and make any suche line with a true ruler, layinge the edge of the ruler to the edge of the circle."
 
As I understand it, both "rule" and "ruler" trace their origin to the Proto-Indo-European "hreg", and then to the Latin "rego", and so forth.
 
All this is my overly pedantic way of suggesting that grumpy shop teachers were simply annoyed that "kids these days" didn't use the same words as they did. 
 
-starlight

I added test results.  

An old trick from the pipe fitter trades where wooden folding rules were still used.  Pipe fitters seldom used the first inch of the rule as the end was likely to worn.  No, everything was not built one inch short.😀. They just moved everything over one inch.
 
 
I too like using triangular architect ‘s scale as I like to build directly in scale dimensions.  As this scales have 10 different scales and one regular inch scale,  there is a possibility of measuring with the wrong scale.  To minimize this, a spring paper at least assures that the scale is laid down with the correct side up.
Roger

The best way to be sure is to spend the money to purchase rules from one of the recognized quality manufacturers. Accurate rules are intended for use with the desired distances taken up with a pair of good dividers. The divider points make accurate measuring easier as small distances can be seen on the rule's markings. Rules should be handled with care and not used as straightedges, especially not for cutting. 
 
A reliable top of the line brand is Starrett. Their instructional bulletin is a gold mine of knowledge on measuring in the shop:    tools-rules---bulletin-1211.pdf (starrett.com) . They have a separate catalog for rules: Precision Rules, Straight Edges & Parallels (starrett.com) Starrett's competition since forever is Brown and Sharpe. One of their six-inch pocket rules will run you around $23.00 at Walmart, but you'll know it's exactly six inches. Brown & Sharpe 599-313-603 Stainless Steel Stainless Rule, 6" Length - Walmart.com On the used market, another very high quality U.S. rule manufacturer to keep an eye out for is Theodore Alteneder & Sons of Philadelphia, which is no longer in business. Similar names from the past are Keuffel and Esser, Dieitzgen, Post, and Bowen.
 
Modeler's will find triangular architects' scales handy. These have six scales, two on each face of the three sides of the triangular-section rule. The scales permit picking up the scale distance directly from the rule without needing to convert measurements to scale each time you take up a measurement.
 

Top 10 Best Scale Ruler (topportalreview.com)
 
Once upon a time, the manual drafting instrument manufacturers made a wide range of scale rules for architects and engineers. (Another type were  "shrinkage rules" made for patternmakers, whose measurements had to take into account the shrinkage factors of various casting metals.) These rules weren't of the newer triangular pattern, but, rather, each flat rule had two scales, one on each edge. They were beautifully made of boxwood and came in cased sets. There are out there drifting around. If you ever see one for a price you can afford, grab it, because they aren't making these beauties anymore.
 

 
 
 
 
 
 

The best way to be sure is to spend the money to purchase rules from one of the recognized quality manufacturers. Accurate rules are intended for use with the desired distances taken up with a pair of good dividers. The divider points make accurate measuring easier as small distances can be seen on the rule's markings. Rules should be handled with care and not used as straightedges, especially not for cutting. 
 
A reliable top of the line brand is Starrett. Their instructional bulletin is a gold mine of knowledge on measuring in the shop:    tools-rules---bulletin-1211.pdf (starrett.com) . They have a separate catalog for rules: Precision Rules, Straight Edges & Parallels (starrett.com) Starrett's competition since forever is Brown and Sharpe. One of their six-inch pocket rules will run you around $23.00 at Walmart, but you'll know it's exactly six inches. Brown & Sharpe 599-313-603 Stainless Steel Stainless Rule, 6" Length - Walmart.com On the used market, another very high quality U.S. rule manufacturer to keep an eye out for is Theodore Alteneder & Sons of Philadelphia, which is no longer in business. Similar names from the past are Keuffel and Esser, Dieitzgen, Post, and Bowen.
 
Modeler's will find triangular architects' scales handy. These have six scales, two on each face of the three sides of the triangular-section rule. The scales permit picking up the scale distance directly from the rule without needing to convert measurements to scale each time you take up a measurement.
 

Top 10 Best Scale Ruler (topportalreview.com)
 
Once upon a time, the manual drafting instrument manufacturers made a wide range of scale rules for architects and engineers. (Another type were  "shrinkage rules" made for patternmakers, whose measurements had to take into account the shrinkage factors of various casting metals.) These rules weren't of the newer triangular pattern, but, rather, each flat rule had two scales, one on each edge. They were beautifully made of boxwood and came in cased sets. There are out there drifting around. If you ever see one for a price you can afford, grab it, because they aren't making these beauties anymore.
 

 
 
 
 
 
 

The best way to be sure is to spend the money to purchase rules from one of the recognized quality manufacturers. Accurate rules are intended for use with the desired distances taken up with a pair of good dividers. The divider points make accurate measuring easier as small distances can be seen on the rule's markings. Rules should be handled with care and not used as straightedges, especially not for cutting. 
 
A reliable top of the line brand is Starrett. Their instructional bulletin is a gold mine of knowledge on measuring in the shop:    tools-rules---bulletin-1211.pdf (starrett.com) . They have a separate catalog for rules: Precision Rules, Straight Edges & Parallels (starrett.com) Starrett's competition since forever is Brown and Sharpe. One of their six-inch pocket rules will run you around $23.00 at Walmart, but you'll know it's exactly six inches. Brown & Sharpe 599-313-603 Stainless Steel Stainless Rule, 6" Length - Walmart.com On the used market, another very high quality U.S. rule manufacturer to keep an eye out for is Theodore Alteneder & Sons of Philadelphia, which is no longer in business. Similar names from the past are Keuffel and Esser, Dieitzgen, Post, and Bowen.
 
Modeler's will find triangular architects' scales handy. These have six scales, two on each face of the three sides of the triangular-section rule. The scales permit picking up the scale distance directly from the rule without needing to convert measurements to scale each time you take up a measurement.
 

Top 10 Best Scale Ruler (topportalreview.com)
 
Once upon a time, the manual drafting instrument manufacturers made a wide range of scale rules for architects and engineers. (Another type were  "shrinkage rules" made for patternmakers, whose measurements had to take into account the shrinkage factors of various casting metals.) These rules weren't of the newer triangular pattern, but, rather, each flat rule had two scales, one on each edge. They were beautifully made of boxwood and came in cased sets. There are out there drifting around. If you ever see one for a price you can afford, grab it, because they aren't making these beauties anymore.
 

 
 
 
 
 
 

The best way to be sure is to spend the money to purchase rules from one of the recognized quality manufacturers. Accurate rules are intended for use with the desired distances taken up with a pair of good dividers. The divider points make accurate measuring easier as small distances can be seen on the rule's markings. Rules should be handled with care and not used as straightedges, especially not for cutting. 
 
A reliable top of the line brand is Starrett. Their instructional bulletin is a gold mine of knowledge on measuring in the shop:    tools-rules---bulletin-1211.pdf (starrett.com) . They have a separate catalog for rules: Precision Rules, Straight Edges & Parallels (starrett.com) Starrett's competition since forever is Brown and Sharpe. One of their six-inch pocket rules will run you around $23.00 at Walmart, but you'll know it's exactly six inches. Brown & Sharpe 599-313-603 Stainless Steel Stainless Rule, 6" Length - Walmart.com On the used market, another very high quality U.S. rule manufacturer to keep an eye out for is Theodore Alteneder & Sons of Philadelphia, which is no longer in business. Similar names from the past are Keuffel and Esser, Dieitzgen, Post, and Bowen.
 
Modeler's will find triangular architects' scales handy. These have six scales, two on each face of the three sides of the triangular-section rule. The scales permit picking up the scale distance directly from the rule without needing to convert measurements to scale each time you take up a measurement.
 

Top 10 Best Scale Ruler (topportalreview.com)
 
Once upon a time, the manual drafting instrument manufacturers made a wide range of scale rules for architects and engineers. (Another type were  "shrinkage rules" made for patternmakers, whose measurements had to take into account the shrinkage factors of various casting metals.) These rules weren't of the newer triangular pattern, but, rather, each flat rule had two scales, one on each edge. They were beautifully made of boxwood and came in cased sets. There are out there drifting around. If you ever see one for a price you can afford, grab it, because they aren't making these beauties anymore.
 

 
 
 
 
 
 

The best way to be sure is to spend the money to purchase rules from one of the recognized quality manufacturers. Accurate rules are intended for use with the desired distances taken up with a pair of good dividers. The divider points make accurate measuring easier as small distances can be seen on the rule's markings. Rules should be handled with care and not used as straightedges, especially not for cutting. 
 
A reliable top of the line brand is Starrett. Their instructional bulletin is a gold mine of knowledge on measuring in the shop:    tools-rules---bulletin-1211.pdf (starrett.com) . They have a separate catalog for rules: Precision Rules, Straight Edges & Parallels (starrett.com) Starrett's competition since forever is Brown and Sharpe. One of their six-inch pocket rules will run you around $23.00 at Walmart, but you'll know it's exactly six inches. Brown & Sharpe 599-313-603 Stainless Steel Stainless Rule, 6" Length - Walmart.com On the used market, another very high quality U.S. rule manufacturer to keep an eye out for is Theodore Alteneder & Sons of Philadelphia, which is no longer in business. Similar names from the past are Keuffel and Esser, Dieitzgen, Post, and Bowen.
 
Modeler's will find triangular architects' scales handy. These have six scales, two on each face of the three sides of the triangular-section rule. The scales permit picking up the scale distance directly from the rule without needing to convert measurements to scale each time you take up a measurement.
 

Top 10 Best Scale Ruler (topportalreview.com)
 
Once upon a time, the manual drafting instrument manufacturers made a wide range of scale rules for architects and engineers. (Another type were  "shrinkage rules" made for patternmakers, whose measurements had to take into account the shrinkage factors of various casting metals.) These rules weren't of the newer triangular pattern, but, rather, each flat rule had two scales, one on each edge. They were beautifully made of boxwood and came in cased sets. There are out there drifting around. If you ever see one for a price you can afford, grab it, because they aren't making these beauties anymore.
 

 
 
 
 
 
 

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

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. 

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. 

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?

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. 

 
 
 

Thanks, gentlemen, for your continued moral support!
 
**********************************************
 

Quarter-deck – further work
 
Having now satisfactory wooden decking for the quarter-deck, this was permanently cemented into place, allowing to progress with the installation of the various bits and pieces that had been fabricated years ago. These include the anchor capstan, the four patent chain-stoppers, chain-bollards (which are hollow and double as a base for the crew accommodation ventilators), various eye-bolts to which stoppers are shackled, that secure the chains during mooring, and the forward pair of mooring bollards.
 

Populated quarter-deck
 
Probably the only bought-in item will the studded anchor-chain. Recently, some really good 3D-printed chains have become available. My excuse is that that many shipyards did not make the chains themselves either, but bought them from specialised forgeries (apart from the fact that I didn’t want to go insane over making such microscopic studded chains). I choose the smallest size from yxmodels (Product no. YXN700-001). With 8€ plus shipping for a length of 120 mm they are the most expensive (not considering my time) item on board. They are printed in a light brown resin and were given several light dusts with acrylic paint to turn them black without clogging up or cementing the links together. The connecting link with the anchor shackle was bent from 0.2 mm tinned copper wire.
 
The anchors are held in place with chains attached to the release gear that had already been installed. These chains were imitated by twisting together two strands of 0.1 mm blackened copper wire so that each twist is about the length of the assumed link length. The length of twisted wire then was folded over in half and twisted together in the opposite sense. With some imagination this looks quite like a slightly twisted chain. The anchor were secured in place with a couple of dots of shellack and then release chains installed – which not unexpectedly was a really fiddly task.
 
I arranged the chains as they would be kept ready for dropping the anchor or in light weather, without further securing by rope chain-stoppers, as I do not have any pictorial evidence for how that would have been done on the real ship. 
 
The quarter-deck later will receive some light weathering and the chain-rails need to be installed, but as they are extremely fragile, this will be put off to the moment, when the model is installed on its final base-plate.
 

Populated quarter-deck
 
To be continued ....

In the US, it seems the jewelers call it "electroforming' (as opposed to the similar "electroplating.") There are many tutorials about the process, most for jewelers, on YouTube. 
 
 

Nils, I became curious about whether any of the movie film Tompkins took of Wander Bird's voyage around the Horn might have found its way onto the internet. I found this piece on YouTube, a newsreel clip that is, of course, dated and quite hokey to our modern eyes, but full of pictures of the deck details which may be hard to find elsewhere. Enjoy!:
  
  

I know her well. She was on S.F. Bay for many decades, known as Wander Bird.  She was a rig-less houseboat in Sausalito when I first met her in the early seventies, thirty years or so after she'd completed her voyage west around Cape Horn to San Francisco before the War. Warwick Tompkins had skippered her around the Horn with his wife, two young children, and a paid hand. Warwick was a well-known local yachtsman, as to this day is his son, Warwick "Commodore" Tompkins, who was four at the time of their voyage.
Warwick M. Tompkins wrote two books about his family's voyage around Cape Horn in Wander Bird: Fifty South to Fifty South, 1938, W.W.Norton & Co., NY and Two Sailors, 1939, The Viking Press, NY, (a story of the voyage written from the perspective of the Tompkins  children.) Both of these books are full of good photographs showing details of the vessel which would likely be very helpful to the modeler. Fifty South by Fifty South,  contains together with the expected narrative of the voyage, an appendix containing many technical details on the vessel . Warwick Tompkins also made a 35mm movie of the voyage entitled In the Wake of the Clippers, which a modeler would probably be interested in watching. I've never seen the movie and I don't know if it is still extant. I'm sure "Commodore Thompkins" would know. I expect he could be reached through the St. Francis Yacht Club in San Francisco.
 
Wander Bird was later acquired by Hal Sommer, a local tug boat skipper and acquaintance of mine, who spent years restoring "the Bird" to mint condition and sailing her on the Bay. Wander Bird was for many years the centerpiece of the classic yacht community on San Francisco Bay. I was fortunate to be able to witness a lot of the work done on her and I learned much about larger wooden shipbuilding by watching Hal, his son Ross, and other "old timers" working on her.  Wander Bird was ultimately sold and moved up to Washington, I believe, and then returned to Germany as a museum ship. 
 
The restored Bird sailing off Yellow Bluff heading home to Sausalito, CA on S.F. Bay. Note the two crew aloft at the mainmast doubling. I have no idea what they are doing up there, other than "skylarking," but I doubt that. Hal ran a tight ship so I doubt they were up there for fun. They wouldn't have been raising setting a topsail in than wind and on that course and there's no evidence of one on deck, 
 

 

 
She carried a rafee topsail earlier in her life:
 

 
I'm looking forward to your build log!

Totally agree with Eberhard's statement.  They will cause more mistakes than doing things the old fashioned way. 
If the third pieces are proposed to be used for rigging, as posted above, make your own, buy some cheap dental tools, or tap your dentist for worn out tools.  
Allan
 

I think the first two items are quite useless, as it is difficult to transfer the necessary dimensions exact enough - it is better (and easier) to work in situ.
 
Not sure what the thingies with the blue handles really are, but probably tools from guys working on circuit boards or something like that. I think an useful rule/guidance is to start work with the tools you have and than at some point, you will discover that you would need to do a certain operation, but cannot do it with the tools you - that is the moment to look for the right tool. Of course, it is always a good idea to look left and right how others do a certain job and what tools they use. Many rigging tools one can make oneself. Sometimes insert for pin-vises are sufficient, which is why I have a hole collection of them. 

Eberhard, an ingenious technique that turned out beautiful. Very well done. 

That would certainly be interesting. I expect there would be a wide band of green patina between the two waterline extremes. I'm not expert on the period, and I'm not sure one way or the other, but I wonder if the Admiralty would spend the money to put copper sheathing on a relatively small water lighter.

Yes, I think this is an excellent option. Small pieces of silkspan may be too fragile to work well, but a very thin paper laid in wet shellac, and then sealed with thin shellac worked well for me. The thickness of the thin paper should approximate the thickness of the prototype copper sheets and the laps should be quire subtle at scale viewing distance. In scales below a quarter inch to the foot, the tacks are not really barely visible at all at scale viewing distances. A very realistic appearing coppered bottom can then be crafted by airbrushing a basecoat of "tarnished copper penny brown" and adding then patchy accents of varying shades of dirty greens and dark browns to simulate fouling, together with a verdigris band at the waterline where the copper develops a patina as it is exposed to the air. (I've used color photos of coppered bottoms from Googled images for "inspiration.")  It can be a tedious exercise in artistic "weathering," but it's very effective if you are showing the hull as it would appear shortly after it was hauled out. For an "as launched" bottom, I'd just use the "copper brown" and skip the weathering patina. I know there was some variation in the color of individual plates, depending upon how much weathering the plate got before it was hung on the hull, and some photos will show a "shiny copper" finish contrasting with the oxidized plates where a plate has just been replaced during a haul out, but, myself, I'd find attaching a patchwork quilt of separately colored individual plates at those scales truly crazy-making. I think it's fair to fudge a little on a hull below the waterline. It is probably the last part of a model to which the viewer's eyes are drawn and an "artistic impression" there is sufficient.