Pomeranian Rahschlup 1846 by wefalck – 1/160 scale – single-masted Baltic trading vessel

[wefalck]

So, this is the beginning of a new adventure. Hopefully, the journey will not be quite as long, as for the previous project.

 

This time, it is about 30 years older, mercantile and with sails: a so-called Pomeranian Rahschlup of around 1846, a somewhat anachronistic sailing vessel from the German Baltic coast. I have a certain attachment to this area which now is called Vorpommern, as part of my family came from this area and were also seafarers.  

 

 

Watercolours of a Rahschlup by Friis-Pedersen (in Friis-Pedersen, 1980, Handels- og Søfahrtsmuseets på Kronborg).

 

Introduction

 

Research on German small coastal trading craft and on this particular type of ship is rather difficult. All physical evidence has long gone, as have the men who built and sailed them. The German literature on commercial coastal craft from the Baltic Sea is quite scarce. Really the only books of some use are those written by Szymanski (1929,1934). He was able to travel much of the area post-WWI to inspect pictorial evidence and collect narrative recollections from people who witnessed the last few decades of commercial coastal sail. Some of his tracings of builders' plans he found at still extant shipyards and with private individuals are now in the Deutsche Technikmuseum Berlin (https://technikmuseum.berlin), but what has not been in public collections during WWII is now largely lost. The war and the lack of care and interest by builders’ and ship owners’ descendants have taken their toll.

 

Surprisingly there were very few serious post-WWII maritime historians in both, Eastern and Western Germany, as well as in Poland, to which now most of now Pomerania belongs, who had an interest in commercial coastal craft. Most historian until today have mainly either an ethnological or an economic interest in the subject and typically very little background in and understanding of shipbuilding. To my knowledge there is no study on the complex interaction between economic and societal developments, resources available, and the technological development of the various coastal ship-building traditions in the 18th and 19th century. Wolfgang Rudolph is one of those exceptions, but he was more interested in the smaller artisanal craft. In more recent years Helmuth Olzsak measured and drew still extant boats around the Mecklenburg and Pomeranian coast (Olzsak, 2014), but he was neither a trained naval engineer nor historian. On the Scandinavian side, both the source availability and their modern evaluation is slightly better.

 

Starting from a wide variety of Baltic craft, as illustrated for instance by af CHAPMAN (1768) for the middle of the 18^th century, by the 2^nd Quarter of the 19^th two types craft seem to have dominated the group of single-masted vessels: the Jacht (or jagt in Danish) and the Schlup (or slup in Swedish and Norwegian). The Jacht was more prevalent west of Rostock, i.e. in western Mecklenburg and Schleswig-Holstein (as in Denmark), while the Schlup occurred more frequently in eastern Mecklenburg and, indeed, in Pomerania. 

 

The Jacht has two distinctive features, a very pronounced sheer (less so in Danish vessels) and a pole-mast, the top of which has a slight curvature forward. They had a flat, heart-shaped transom and carried their rudder outboard. The sail plan consisted of two foresails, a gaff mainsail with a square gaff-topsail. They usually could also set a large square foresail flying. These features were kept right to the end of wooden ship-building at the Baltic coast.

A jagt (‘The Sea’) by C.W. Eckersberg, 1831, Louvre, Paris.

 

The Schlup followed more the fashion of deep-water ship-building of the day. The mast always carried a top-mast. In the 19^th century they were built with little or no sheer and had square or oval transom above the water, with a rudder inboard. The sailplan was similar to that of the Jacht, put the gaff mainsail was usually larger in proportion. She largely resembled those trading craft that would be called a smack in British waters.

There was also one distinctive version of the Schlup that carried a single full mast. As the name in German indicates, the Rahschlup carried a heavier topmast with two topsails. This is a rather lofty rig for a humble sailing coaster, resembling the rig of the British naval cutters and the Swedish packets (CHAPMAN, 1768) of the late 18^th and early 19^th century. As their main area of occurrence was Pomerania, which belonged to Sweden from the days of the 30-Year-War until the Vienna Congress in 1815, they may be descendants of those Swedish packets that secured the connection between Stralsund and southern Sweden.

Rahschlup JOHANNA of Copenhagen (1839), Tamm Collection, Hamburg    

Rahschlup of 1836, Schiffahrtsmuseum Rostock.

 

Such rig required at half a dozen men or so to sail her safely. To the contrary, a Jacht could be handled comfortably by the master and a mate, or even only a boy (cf. Rudolph, 1958, on crewing). By the middle of the 19^th century, such a rig appears rather anachronistic and would have been quite uneconomic. However, it would have had its advantages when working the coastal lagoons (Bodden, Haff) of Pomerania (now partly in Poland) and Eastern Prussia (now divided between Poland and the Russian Federation), as well as the coast of Southern Sweden. Dunes and rocks overgrown with shrubs and light woods would blanket near-surface breezes.

DER JUNGE PRINZ (1819), painted 1832, Schiffahrtsmuseum Rostock

 

Pictorial evidence from the middle of the 19^th century shows a fairly uniform arrangement of loose-footed gaff mainsail (the gaff being considerably longer than the one on a Jacht, which would also be curved), a square gaff-topsail set flying on a light yard, and two (sometime a flying third one is seen) headsails. Like on the foremast of a topsail-schooner, there was a main yard below the trestle-tree and two light yards running on the topmast and spreading two topsails. A rather large square foresail could be bent to the main yard. In the earlier days a full complement of lee-sails may have been carried as shown on various ‘captain’s-paintings and one or two rare photographs from Norway, where this rig seems to have survived the longest.

 

The mast was supported by three to four fully webbed shrouds and a couple of backstays set on tackles. The topmast was supported by shrouds to the trestle-trees only - apparently no backstays were used. The mast also had the usual complement of stays leading to the bowsprit and a fixed jibboom. Unlike to what was the fashion in deep-water sail during the 1840s, the masts of the Rahschlup had virtually no rake.

Norvegian slup EXPRESSE (1842), Sandefjordmuseene.

 

The Schlup ranged in length between 10 and 25 m with a width of as much as 7 m and a depth of up to 3.5 m according to Szymanski (1929, 1934). The Rahschlup naturally tended to be at the upper end of the range. She was always built carvel with a medium sharpness in the waterlines, a rising floor and usually some tumblehome. The entrance was rather bluff (certainly above the water), the run with some hollow. The sheer practically disappeared from the second quarter of the 19^th century onward (as was indeed the fashion with larger seagoing vessels at that time). The stem was slightly curved or straight with only a little rake. The sternpost had considerable rake on top of which sat a gilling and it was crowned by a transom that became smaller over the time. The rudder ran inside and was nearly always worked with a tiller.

Norvegian slup GLÆDEN (1836), Norsk Maritimt Museum, Oslo.

 

Typically, the deck was flush, but could also have a raised quarterdeck, as was usually the case for the Jacht. There would have have been a small hatch before the mast and a larger one after the mast. Small companionways provided access to the crew's quarters between the small hatch and the spill and to the main cabin in the stern respectively. A small portable caboose lashed to the deck is often seen on paintings. The compass would live together with its lights in a housing with sliding doors lashed to the deck within convenient distance for the helmsman.

 

Davits over the transom were provided for stowing the dinghy, which was, however, often towed. On some Schlups a larger boat was stowed was stowed in chocks on the main hatch behind the mast.

 

Mechanical devices to make heavy work easier were, of course, an anchor spill in association with the post providing the footing of bowsprit and a cargo winch behind the mast. The anchor spill followed the technological development of the time from its simple form with an eight-sided trunk to the more sophisticated patent or pump-spills of the time. Also, the simple wooden pumps would make room to the more efficient cast-iron variety.

Norvegian slup LOFOTEN (1841), Sverresborg Trøndelag Folkemuseum.

 

Concerning the colour-scheme, Schlup would largely follow the fashion of contemporary deep-water sail (as opposed to the Jacht, which seems to have been more conservative). The colour scheme developed from scraped and oiled sides with black wales up to the early years of the 19^th century to one with several strakes in different pale colours, such as pale blue, green or brown, and white, while the whale remained usually scraped and oiled. In later years the whole hull above the water was generally painted black with white rubbing strakes and sometimes the wale still scraped and oiled. Below the waterline coal-tar was sufficient in most cases, as these ships normally would not leave the Northern European waters. 

 

The inside of the bulwarks often were painted in pale green, pale blue or pale ochre before the middle of the 19^thcentury, when white generally became the preference.

 

Spars would have been either scraped and oiled in their entirety or would have tops and ends in a colour matching the rest of the ship, i.e. pale green, blue, ochre, or white.

Norvegian slup PRØVEN (1847), Sverresborg Trøndelag Folkemuseum.

 

Their trade

 

As was mentioned earlier, their main area of operation was the Baltic Sea, with journeys round Skagen to harbours along the German, Dutch, Belgian, Norwegian and British North Sea coasts. Some may have traded as far as the Mediterranean (in which case they would have to be sheathed in copper or zinc), bringing back fruit and wine in exchange for e.g. wheat (Mecklenburg), hemp and pitch (Baltic states, Russia) or perhaps salted herring. Bricks (‘Flensborg stone’) and masonry blocks (from e.g. Bornholm, Gotland and Skane/Southern Sweden) might have also been commodities of interest for areas, where either the raw materials (clay) or the fuel (wood) to process them were lacking.

 

Those registered in Schleswig or Holstein, however, would have carried the Danebrog until 1864 and could have traded freely to the Danish Westindies (https://en.wikipedia.org/wiki/Danish_West_Indies), now US Virgin Islands.

 

To be continued

 

[KeithAug]

This looks like an interesting challenge Eberhard. The rig looks to be reasonably well defined but I am not sure how you are going to get a lot of the deck detail. I will enjoy watching how you progress.

[Keith Black]

 Eberhard, this looks to be an interesting project. I'm on board for the journey.

Edited October 31 by Keith Black

[Doreltomin]

A really interesting project! Unfortunately much of this rich heritage of the Baltic trade is almost lost so you surely will do them some justice by drawing attention to these ship types. Also I must add a special mention to these wonderful pictures which you amassed here to illustrate the ships. A big thank you for the thread, will surely follow with much interest!

[BANYAN]

I look forward to following this build (as I have your previous builds) Eberhard.  You pick some very interesting subjects for your models.

 

cheers

 

Pat

[Jim Lad]

What an interesting looking coastal ship type, Eberhard. It will build a beautiful model.

 

John

[druxey]

Congratulations on launching your new project, Eberhard. Lovely subject!

[Ras Ambrioso]

I admire your work. Count me in on this one. 

[Bedford]

I'm hopping aboard again too, that's a very pretty and interesting subject for a model.

[Mirabell61]

a good choise Eberhard,

and a very interesting project. I wish you a successful keellaying session soon.

It promises to be a fine scratch built vessel on MSW

 

Nils

Edited August 14 by Mirabell61

[mbp521]

Count me in on this one as well. Looks like a fun build.

 

-Brian

[wefalck]

Thanks for your initial interest!

 

*******************************

The basis for the model reconstruction

 

The model will not depict a specific ship, rather the reconstruction will be for the ‘type’, based on a set of drawings by a Joachim Möller (who was a builder in Rostock) dated to 1846 and preserved in the archives of the Rostock Maritime Museum (https://schifffahrtsmuseum-rostock.de). It is not known, to which ship, as they were not named, nor was a client indicated on the drawings. 

 

 

 

Sail plan and lines drawings of a Rahschlup drawn by Joachim Möller, dated 1846, Schiffahrtsmuseum Rostock.

 

They follow the practice of the time and give line and body plans as well as side elevation/longitudinal section and a sail-plan. This allows to reconstruct much of the deck-layout and the dimensioning of the visible woodwork. The sail-plan also contains a table with the spar dimensions.

 

Much of the details of the deck, the rigging and other fittings will have to be reconstructed from contemporary paintings and photographs of similar craft that survived into the late 19^th or even into our times.

 

A valuable source of information are the books by Friis-Pedersen (1980 and1983), and Funch (1833 and 1846). Interestingly, the water-colours by Friis-Pedersen reproduced above show a Rahschlup virtually identical to that of the plans by Joachim Möller, but I doubt that Friis-Pedersen had access to these drawings, which were located in the GDR at the time.

 

General information on contemporary building practice in Germany can be found in Klawitter (1835) and Steinhaus (1858), which bracket the time, when this Rahschlup was designed. Masting and rigging details can be obtained from Bobrik (1848), Biddlecombe (1848), and Steinhaus (1869). The two Danish jagt measured by Nielsen (1973) give details on dimensions of scantlings and other parts, which are useful for upscaling. One should also not forget the detailed drawings of a Danish jagt in the ‘Souvenirs de la Marine’ by Pâris.

 

Other more or less contemporary (text)books on shipbuilding and rigging will be also consulted, but with caution, as they typically reflect the practice in larger ocean-going vessels. However, tables on spar and rigging proportions are still useful.

 

 

Various useful resources

 

No Web-site covering this type of coastal craft could be found yet (apart from my own).

 

There are, however, some sites that feature a Jacht, jagt (Danish), jakt (Swedish) or slup (Norwegian, Swedish) under restauration. The most interesting site was the one documenting the restoration of the small Norvegian slup RUTH (1854, https://www.sluppenruth.dk), however the many photos of the process seem to have disappeared from their Web-site since I downloaded them five years ago. The restoration project for the Danish Jagt 'JENSINE AF HADERSLEV' (https://www.jensine.dk) from 1852 is also interesting, because the photographs show many original details of such and the steps of reconstructing unsound or missing parts. It should be noted that all these restorations altered the original deck-layouts with a view to accommodate the needs of cruising vessels and modern safety at sea requirements.

 

A replica of a Danish Jagt has been constructed at the museum shipyard of Flensburg on the basis of the lines of the DE FIRE BRØDRE (1794), whose lines are reproduced in NIELSEN (1973). Unfortunately, their Web-site does not give any details on this project beyond the launch that took place in 2009. Pictures of her construction can be seen here:https://www.arbeitskreis-historischer-schiffbau.de/mitglieder/ontour/flenswerft/.

 

The Altonaer Museum in Hamburg has a fine collection of models of small 19^th century merchant sailing ships. These models were constructed in 1/24 scale between 1909 and 1912 from plans in the museum collection and plans on loan from various shipyards of the region (Timmermann, 1974) by a boatbuilder, a blockmaker and a sailmaker. While these models are not contemporary to their prototypes, their builders were presumably close enough to the time to have reproduced reasonably well the then current practices of construction and rigging. Below are two pictures of the Schlup ELBE (1836). More pictures of these models can found at https://www.maritima-et-mechanika.org/maritime/hamburg/altona.html.

Model of the Schlup ELBE (1836) in 1/24 scale. Built by D. Behrens in Schulau (near Hamburg) for Hans Oestmann (Inv. Nr. AB 1813, Altonaer Museum, Hamburg) 

 

Over the years more and more museum holdings in terms of drawings and paintings have been digitised and made available through the Internet, namely those of the (maritime) museums of Denmark, Norway, and Sweden. This allowed to consult numerous paintings of Norvegian and Swedish slups and Danish jagts.

 

Literature

 

As for graphical resources, most of the literature listed below has become available as digital copies over the past 20 years, which allows to consult even rather rare books remotely.

 

BIDDLECOMBE, G. (1848): The Art of Rigging.- 155 p., Salem, Ma. (Reprint 1990 by Dover Publication, New York).

 

BOBRIK, E. (1846): Handbuch der praktischen Seefahrtskunde.- Vol. 1-7: 2688 p., 50 pl. Zürich/Hamburg (Julius Fröbel & Co./Hoffman & Campe).

 

Chapman, H. Af (1768): Architectura Navalis Mercatoria.- 103 pp., Rostock (Reprint 1968 at VEB Verlag Hinstorff).

 

Fleischfresser, K., Hoffmann, R. (1975): Segler von Haff und Bodden. Pommersche Küstenschiffahrt.- 96 pp., Hamburg-Norderstedt (Verlag Egon Heinemann).

 

[Friis-Pedersen, J.] (1980): Sejlskibe - Danskbyggede traeskibbe opmålt, tegnet og fotograferet.- Handels- og Søfahrtsmuseets på Kronborg Søhistoriske Skrifter IX: 107 pp., København (Høst & Søn).

 

[Friis-Pedersen, J.] (1983): Sejlskibe - Nordiske fartøjer opmålt, tegnet og fotograferet.- Handels- og Søfahrtsmuseets på Kronborg Søhistoriske Skrifter XI: 96 pp., København (Høst & Søn).

 

Funch, D.H. (1833): Praktisk Skibbyggerie. Et Forsøg.- 76 folding (some are quite large) lithographed plates, including 28 in full color & many others tinted or heightened in color. 76 pp., 1 leaf of errata; 64 pp.; 223, [4] pp., 1 leaf of errata. Three parts in one vol., Kjøbenhavn (Luno & Schneider).

 

Funch, D.H. (1843): Afhandling om coffardiskibes constructionen. Et Forsøg.- 2 bd. (6) + 74 + (2) +92 p., 17 fold. plancher, 9 tabeller og 3 blade med forklarende tekst, Kjøbenhavn (trykt paa Forfatterens Forlag).

 

Funch, D.H. (1846): Dansk Marine-Ordbog, 1ste Part.- 170 pp. + 67 Pl., Kjøbenhavn (Forfatterens Forlag, reprint 1976 by Høst & Søn, Copenhagen).

 

Gøthche, M. (1980): Sluppen Ruth – rapport om restaurering af Nationalmuseets slup..- Maritim Kontakt, 1: 59-77, København.

 

Klawitter, K.G. (1835): Vorlegeblätter für Schiff-Bauer für die Königlichen Schiffbau-Schulen.- 40 pp., Berlin (Petsch, reprint 1978 by H. Hamecher, Kassel).

 

Monrad Møller, A. (1988): Jagt og skonnert. Studier i den danske provinssøfart i tiden fra 1814 til 1864.- 273 p., København (Forlaget Falcon).

 

Nielsen, C. (1973): Danske Bådtyper.- 152 pp., København (Høst and Søns Forlag).

 

Olszak, H. (2014): Hölzerne Fischereiboote der südlichen Ostseeküste. Vermessene Relikte und rekonstruierte Zeitzeugen.- 276 p., Henningsdorf (Eigenverlag Michael Sohn/Sohn-Art).

 

Rudolph, W. (1958): Die letzten hölzernen Frachtfahrzeuge der kleinen Küstenfahrt auf Rügen (m. Pers.-Literaturangaben u. Abb.).- Balt. Stud., NF, 45: 137-43.

 

Rudolph, W. (1958): Die Schiffstypen der ländlichen Frachtschiffahrt in den Gewässern der Insel Rügen.- Dt. Jb. f. Volksk., IV: , Berlin (Ost).

 

Rudolph, W. (1962): Rügischer Schiffbau auf den Werften zu Seedorf.- Greifswald-Stralsunder Jb.: ?.

 

Rudolph, W. (1966): Handbuch der volkstümlichen Boote im östlichen Niederdeutsch-land.- 150 pp., Berlin (Akademie Verlag).

 

Rudolph, W. (1969): Segelboote der deutschen Ostseeküste.- 145 pp., Berlin (Akademie Verlag).

 

Steinhaus, C.F. (1858): Die Schiffbaukunst in ihrem ganzen Umfange – I. Theil: Die Theorie der Schiffbaukunst, II. Theil: Die Schiffbaukunst in der Praktik.- 158+170 pp. + 4 Tafeln, Hamburg (P. Salomon & Co., reprint 1977 by Horst Hamecher, Kassel).

 

Steinhaus, C.F. (1869): Die Construction und Bemastung der Segelschiffe.- 137 pp., Hamburg (L. Friedrichsen & Co., reprint 1977 by Horst Hamecher, Kassel).

 

Szymanski, H. (1929): Zur Geschichte der schleswig-holsteinischen Jachten im 19. Jahrhundert.- Der Kleinschiffbau – Z. f. Gebrauchs- u. Sportfahrzeuge aller Art, ?: 209f., Berlin.

 

Szymanski, H. (1929): Die Segelschiffe der deutschen Kleinschiffahrt.- Pfingstblätter des Hansischen Geschischtsvereins, Bl. XX, 81+XXI pp., Hamburg.

 

Szymanski, H. (1934): Deutsche Segelschiffe.- Veröff. Inst. f. Meereskunde, N.F. B, H. 10: 167 pp. + 92 Taf., Berlin.

 

Timmermann, G. (1974): Das Schiffbauhandwerk.- Schausammlungen des Altonaer Museums, H. 1: 93 p., Hamburg (Altonaer Museum).

  

To be continued

[Gregory]

Interesting subject.

 

The sails on the museum model look really good.

[Ras Ambrioso]

Wefalk, I love you research.

[archjofo]

@wefalck

Hello Eberhard,

After successfully completing the wonderful model of the "SMS Wespe" you have started another very interesting model building project. The shipbuilding background alone is very exciting.

I'm looking forward to the continuation.

[wefalck]

Design of the model

 

The idea for the project was conceived back in around 1980, when I became aware of the 1934 book by Szymanski and the drawings therein. Unfortunately, the tracing of the original builder’s plan for the purpose of the book was done very summarily and all the usual details are missing. I could not locate the original drawing, as it must have been in the possession of the builder’s family at the time and is probably lost now. 

 

 

Lines and sail plan of a Rahschlup, drawn in 1852 by H.P. Steffen, Lübeck (from Szymanski, 1934)

 

Then in the later 1990s I discovered the drawings by Joachim Möller in the archives of Rostock Maritime Museum, who kindly provided me with copies. After a lot of procrastination and detours I started the S.M.S. WESPE project, which took much much longer than anticipated. In between, I made several attempts to redraw the lines for the purpose of model reconstruction. My oldest files are still in ClarisWorks … As I am now trying to recuperate the work I did several years ago, I found it somewhat difficult to remember what I did at the time and what my intentions were for construction.

 

The drawings by Joachim Möller allow to take off a few key dimensions, but it does not give the dimensions of the scantlings. However, the measurements taken by Nielsen (1973) off the jagt CASTOR (1867) give a basis for extrapolation. CASTOR was 48’ between the perpendicles, as opposed to 64’ for the Rahschlup. It is not known, which foot Möller used, it could have been the Mecklenburg or the Rhineland-Prussian, which was in widespread use and is identical to the Danish one at 314 mm. For convenience sake I assumed that it was that latter. Based on the (crude) assumption that all parts are proportionally bigger in the bigger ship, I developed a conversion table that shows the upscaled dimension and the dimensions in the chosen 1/160 scale.

 

Conversion table that calculates the scale dimensions for the reconstruction

 

The construction will be plank-on-bulkhead for a waterline model. Unlike for larger ships, the bulwark stanchions were not separate members, but every second  or third frame was extended up to the level of the main rail. Such practice can be seen e.g. in Klawitter (1835). In terms of model construction, this has the advantage, that the hull shape up to the main rail can be easily defined. On the other hand, the body plan does not give all the necessary frame positions, which have to be lofted off the line plan. Likewise, the cant-frames in the bow that reach up to the rail have to be lofted. Contrary full-scale practice, I will also introduce ‘cant-frames’ towards the stern to avoid excessive fairing and bevelling and being able to use one thickness of material (see below).

 

I did quite some lofting in my 2D CAD in the past and now have to go through my older files in order to understand what I did some years ago and how far I actually got. I tended to work on this during vacations, when I had no access to the workshop. I also realised that more lofting needs to be done on the cant-frames.

 

The plan is to cut the bulkheads from 1 mm acrylic glass, which then will be slotted into a solid baseplate of 3 mm acrylic. The slots will be cut in the milling machine. The stem will also be 1 mm acrylic and its final thickness build up with outer layers of styrene in order to be able to create a rabbet without the need to mill it into the solid acrylic.

 

The rationale behind using acrylic glass (Plexiglas) is, that it is isotropic, does not have grain, and holds edges very well. In addition, this material was already in my storage, while sourcing good-quality hardwood (e.g. boxwood) in suitable dimensions is difficult, where I am. Also, Plexiglas does not generate dust, when milled etc. and thus is more friendly in a workshop that is one corner of my study.

 

That is how far the planning and the work have preceded to date. Now back to the drawing-board – or rather the CAD.

 

To be continued

[wefalck]

Just to keep the ball rolling

 

It is not that nothing happened in the background in spite of various travels and work to earn money … 

Much time was spent interpreting the original drawings and to prepare drawings for the actual building process. Luckily the spacing of the frames in the body-plan was such that it equalled the spacing of three frames of the prototype and every third frame would have been elongated to serve as bulwark stanchion. This saved a lot of real lofting, as the bulkheads just had to be copied and the missing details and reference lines needed to be added.

However, cant-frames were not drawn and had to be lofted from the lines- and body-plans. The same for the longitudinal frames that support the transom and the gilling.

As this will be a waterline model, the hull will be constructed on a base-plate. The base-plate will be 4 mm Plexiglas into which 1 mm deep slots for the bulkheads and the stem- and sternpost pieces.  

The size of the drawing 190 mm wide and 145 mm high

 

The drawings will be stuck to 1 mm acrylic glass and sawn out.

 

To be continued

[BANYAN]

4 hours ago, wefalck said:

he drawings will be stuck to 1 mm acrylic glass and sawn out.

An unusual building medium Eberhard. Is this for stability of the frames? I note the base is also acrylic so may be just to make life easier down the road a bit?

 

cheers

 

Pat

[Dr PR]

Wefalck,

I have been doing the same with my MSI build. I am assembling bulkheads to the center frame - not plank on frame - but I realized after I had cut out the bulkheads that I had missed an opportunity.

For planking the hull I amusing a technique where I mark the plank edges on the bulkheads. At midships between the deck and keel there will be 25 planks and the garboard strake. I will taper the planks to be 1/25 the distance along the edge of each bulkhead. For this I am using tick strips and a planking fan. There are 21 bulkheads, and I will need to mark at least every other one.

This would have been MUCH easier if I had just calculated the plank widths in my CAD program and printed lines on the bulkhead templates!!!!! I'll know next time!

Perhaps you can do this on your frame templates.

[wefalck]

Thanks for your interest and comments!

 

@Dr PR One has to keep in mind that the hull will be only about 150 mm in total and the planks will be a maximum of 1.5 mm wide and around the bulwark only 1 mm (= 160 mm on the prototype. I have been thinking about marking the planks on the bulkheads, but with the close tolerances needed, that may not be possible. I started marking out the whale, but that has to be improved still, as the tapering is not yet considered. Tapering the planks at that size will be a challenge. I may calculate the width from the CAD and then make a print-out on paper and try to shape the planks to this paper template. I will have to build a jig to hold the 1.5 mm wide and 0.25 mm thick strips of styrene to be used for planking while trying to taper them.

 

@BANYAN Most people here, of course, would use wood, but at 1/160 scale, covering-up all the wood-grain is a lot of work. It would be completely out of scale. Also, for me it is difficult to obtain and mill hardwood, such as boxwood. Living in a city apartment imposes certain restrictions. As the whole model will be painted, as ships of that time usually were, it doesn't really matter what is underneath. Acrylic glass (particularly the cast variety of PLEXIGLAS®) is an excellent material for machining and can hold very sharp edges, which is needed at this small scale. I still have a good stock, as my father used to work for a subsidiary of the manufacturers of PLEXIGLAS and we got the stuff for little money back then.

[Keith Black]

Eberhard, do you like working at 1:160 scale or is it a case of continuing to work at that scale having geared up to do so early on?  I hope I asked that question clearly. I started with 1:120 and have continued because of tools and leftover inventory. There are times when I wish I had started with 1:87 because of the availability of figures and fittings. 

[wefalck]

There are a couple of reasons: there are figures available at N-scale - it's small, which is important, when you don't have a lot of space for large models - and it is challenge to try to put as much detail into it, as one typically would put into something twice or three times the scale 😉

 

1/150 to 1/160 scale is still big enough so that one can find suitably thin materials for representation in scale.

[wefalck]

Started to make chips

 

There was still some re-drawing and re-lofting to be done, as I realised that some parts of the planned back-bone did interfere with each other and cut-outs for the deckshouses etc. were missing. 

 

I then did a test-printout in order to detect any scale aberrations of my laser-printer. It turned out that the printouts were 0.5% too small, which was corrected by enlarging the drawing before printing accordingly. Then the printout was spot on with the desired dimensions.

 

The base of the construction will be a piece of 4 mm thick acrylic glass. The printout was stuck to the acrylic with a glue-stick and then crucial intersections of lines and boreholes punch-marked. The centre-lines for the slots into which the bulkheads will were scored along the centre with a scalpel. This will help to align the base for milling.

Layout for the backbone on 4 mm acrylic glass

 

Cutting out the backbone on the small PROXXON scrollsaw

 

The backbone was cut out with my PROXXON scrollsaw, but I am not terribly good at that, so I ended up quite far away from the line. However, the micro disc-sander that I build a few years ago from watchmakers lathe part came to good use here. Different diamond discs quickly and precisely removed the excess.

Shaping the backbone with the micro disc-sander

 

The backbone then was screwed down onto a batten that will allow to safely hold the model in a vice etc. during the building process. With the aid of this ‘building board’ the backbone was mounted in a vice on the rotary table of the lathe. It was checked that the backbone was perfectly perpendicular to the cutting spindle in all directions. This necessary in order ensure that the slots have an equal depth everywhere. The bottom of the slots will be the vertical datum for the alignment of the bulkheads. Finally the backbone was aligned to the axes of the milling machine.

 

Set-up on the milling machine for milling the slots for the bulkheads 

 

All the slots, with the exception of those for the cant-frames were milled in the same set up, which ensures that the slots are parallel to each other and the slots for the stem- and sternpost are at a right angle to the bulkhead.

 

Set-up on for milling the slots for the cant-frames 

 

For milling the slots for the can-frames the ‘building-board’ had to be moved so that centre, where the cant-frames would meet is roughly in the centre of the milling table. By turning the rotary table, the slots were aligned to the y-axis of the milling machine.

Milling the slots for the cant-frames 

The back bone with the slots ready to take up the bulkheads

 

After removing the paper template with warm water and some light deburring the backbone is now ready for the bulkheads.

 

To be continued

[ccoyle]

At one time I thought I had some ancestors from Pomerania. All I knew at first is that they were from 'Pommern', so it was a natural assumption to make. I later learned that they were from the other Pommern -- the village in Rhineland-Palatinate. A big difference!

[Jim Lad]

Nice to see the sawdust flying, Wefalck!

 

John

[tkay11]

This is a really nice technique, Wefalck. Could easily be applied to wooden bases, but I'm intrigued by the machining of the acrylic.

 

Thanks very much.

 

Tony

[wefalck]

Thanks gentlemen for your as always encouraging comments!

 

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Digression

 

I wanted to use the die-filer I build some years ago from a broken jigsaw attachement (https://www.maritima-et-mechanika.org/tools/diefiler/diefiler.html) as a scroll-saw instead of the PROXXON. Here I can control the speed down to 0 and there is a clearance of only about 1 mm around the blade, which is important when working on the delicate parts of the bulkheads.

 

I had contemplated down-holds for the workpieces, but never got around to make one and so far, it was not needed for my filing operations. However, it became quickly apparent that sawing would not be possible without, as the sawblade hooked on the upstroke taking the part with it and breaking the sawblade in the process.

 

There are several designs of down-holds on commercial die-filers, but they require all a lot of machining. In the end I opted for a design similar to that of the PROXXON scroll-saw, but without the blade-guide, as I wanted to use it also with very fine machine-files. To this end I had to modify the overarm by drilling a hole for the stem and another tapped one perpendicular to it for the thumbscrew to set the down-hold. The down-hold itself resembles the foot of a sewing-machine and was milled from a piece of 5 mm x 10 mm aluminium bar. 

Downhold for the die-filer

 

This scroll-saw now allows to make precise cuts on very delicate parts, though I definitely need to practice working with it.

 

 

Digression No. 2

While the die-filer is an excellent tool for fine surface treatment, sometimes a router would be more convenient, particularly when working on concave surfaces. It can also be used with appropriate tooling for bevelling edges of irregular parts, which is possible on the die-filer but requires more complicated set-ups.

Underside of the router table

 

Stationary routers normally have the spindle under the table, but this is mainly a design convenience. I did not want to build a new machine, but utilise what I already have, namely the micro-mill built a few years ago (https://www.maritima-et-mechanika.org/tools/micromill/micromill.html).

Set-up for free-hand shaping concave edges

 

The design-specifications set out called for the use of common jewelers’ milling bits with 2.35 mm shaft or perhaps small carbide end-mills with 3 mm shaft. Thus, the largest ‘router bit’ diameter would be 3 mm. 

Guiding pin held in collet underneath router table

 

I had a steel disc of 60 mm diameter and 10 mm thickness knocking about for many years, which should have become a face-plate for the watchmakers lathe, but since then I was able to acquire an original one. This disc now was reassigned to become the router table. This table should fit onto the spindle of the dividing head. The idea behind it was, that I then could use pins held in a collet inside as guiding pins, e.g. for bevelling irregularly shaped edges.

Set-up for bevelling edges with the aid of a guiding pin

 

The steel disc was turned flat on both sides, a 3 mm hole drilled and reamed (for appearance, rather than mechanical need) and bored out to a depth of 8 mm for a very light press-fit over the spindle end. Et voilà, we have router.   

Bevelling edges of irregular edges

 

To be continued

[BANYAN]

Excellent modification and 'tool-ology' Eberhard.  As usual, your workmanship is 'par excellance'.

 

cheers

 

Pat

Edited December 1 by BANYAN

[wefalck]

Thank you Pat !

 

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Cutting out the bulkheads

 

It took some time to figure out an efficient and precise way to cut out the bulkheads form the 1 mm thick acrylic glass. Unfortunately, the router table did not prove as useful as I thought, it was difficult to achieve smooth curves, as the cutter tended to bite into the material. So, I resorted to good old hand-filing.

 

I also observed that when sawing and grinding/filing the stuck-on paper frayed and it became difficult to see the lines. Sticking the template with the printed face onto the clear acrylic glass instead the usual way solved that problem. The printed lines were protected to the end by the acrylic glass and one could work very precisely towards it.

 

Initially, I also used a too narrow scroll-saw blade, which tended to wander. Using a slightly coarser and therefore wider blade sorted that.

 

The process then was: cutting strips of acrylic glass just the height of the bulkheads on the circular saw; cutting out the paper templates with about a millimetre around them and sticking them onto the acrylic glass ‘face down’; the bulkhead then was roughly cut out on the scroll-saw. In the next step the part was transferred to the disc-sander and the outside of the bulkhead was shaped on it; the final step consisted of draw-filing the inside shape of the bulkhead with the part held in a small precision-vise. The bottom edge does not need any work, as the cut with the circular saw is smooth and exactly perpendicular.

Rough cutting out the bulkhead on the scroll-saw

Shaping the outside of the bulkhead on the disc-sander to the line

Filing the inside of the bulkhead to the line in a precision-vise

 

This process is slow and I only managed to eke out time for one bulkhead each evening between various pre-Christmas duties and more business travel.

 

To be continued