wefalck

I think you painted a quite convincing picture of the history (or of the lack of knowledge about it). Relating the lancha to the botter is bizarre, as neither the shape nor the construction bears any resemblance to it. A botter doesn't have a true keel, but rather a wide bottom plank, for instance. It has been observed in other regions of the world that local boatbuilders began to adapt their types, when European tools, materials, or ways of producing half-finished goods, such as sawn lumber became available, resulting in more efficient processes, albeit at higher capital cost. Local boatbuilders may have also copied features of European craft because they were either more efficient or more 'fashionable'. Examples are the Inuit that started to use European sawn planks in their kajak construction or the Arab dhows that adopted the high square stern of the European 16th galeons once they came into contact with the Portuguese. Around the European coasts boats and small trading or fishing craft often were built be part-time builders, whose main occupation may been farming for instance. They were often built for their own use, sometimes with the advice and help of a professional boatbuilder. So it is quite conceivable that locals would put together boats basec on whatever example they may have come across.

Thank you Pat ! ***************** 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

I use neither, only safety goggles (with or without built-in magnification), but then I rarely use the chucks for model work, only for my tool-making. For really fine work, where you have to look at the work from different angles, face shields are impractical.

Nice re-purposing and probably quite in the spirit of these ships that presumably also were built with whatever was handy at the yard.

I have a basic workshop safety-rule: I keep my face/head out of the line-of-flight of spinning objects as much as possible. When working with the lathe, I am always with my body slightly to the right from a spinning chuck. They also sell round polycarbonate shields for lathes, but they are not very convenient for precision work on small parts.

Keep in mind that the DB250 is a small wood-lathe with only 40 mm centre-height. The Sherline-chucks are designed for much heavier metal-lathes ... The spindle-thread on the DB250 should be 16x1, not sure that Sherline would offer chucks with such a thread. There may be several aftermarket options of Chinese or Indian origin for centric or independent 4-jaw chucks at moderate prices, but they typically have either 12x1 or 14x1 threads, I think. PROXXON offers a plastic independent 4-jaw-chuck, which would be quite adequate for wood-work. As long as you work from stock, the run-out of a chuck is not really important. The part in itself will be true in all its diameters. Run-out only becomes relevant, when you want to perform so-called 2nd operations, i.e. when you inverse a piece and want to work on its unmachined side. Setting up an independent 4-jaw-chuck can be a real pain and is time-consuming. You normally would need a dial-indicator to check for concentricity (there are other approximative methods). However, this can be the most precise option for 2nd operations. Not really needed for most wood-working applications.

Talking about machine tool safety: as far as I am aware the DB250 comes with a set of collets of up 10 mm. This is a much safer and more precise option for working on round stock up to that diameter. There is no risk that your fingers or your tool collides with the chuck jaws ... I use collets almost exclusively on my lathes.

Actually no. I the jaws are reversible as in almost any chuck like that. When the steps are facing inside, you can work on larger and flat items. Other chucks may be delivered with two sets of jaws instead. And: keep towels away from revolving chucks, this could result in a serious desaster otherwise. Also: never work with gloves and loose clothing on a lathe (or mill).

Personally, I think oil is better on scroll-chucks, as grease together with swarf may clog up the rather tight-fitting spirals. I have never used grease on my half dozen or so of different scroll-chucks.

Put some resources to your kit review:

Seems to be based on one of the drawings in Pâris' Souvenirs de la Marine. It would be a good idea to cross reference with some literature, as the dhows do not use European fittings and materials. Since having been to Oman a couple of times (back in the late 1980s) and to Tanzania/Zanzibar (in 2012) I have a certain interest in ships and boats from that region. I have compiled a list of references. Those marked with an E in front are available as digital copies: E Agius, D.A., Cooper, J.P., Zazzaro, C. (2014): The Maritime Heritage of Yemen: A Focus on Traditional Wooden ‘Dhows’.- In: Agius, D.A., Gambin, T., Trakadas, A [Eds] Ships, Saints and Sealore: Cultural Heritage and Ethnography of the Mediterranean and the Red Sea: 143-157, Oxford (Archaeopress). E Agius, D.A., Cooper, J.P., Zazzaro, C., Jansen van Rensburg, J. (2014): The Dhow’s Last Redoubt? Vestiges of Wooden Boatbuilding Tradition in Yemen.- Proc. Seminar Arabian Stud., 44: 71-84. B ANONYM (1979): Oman, a Seafaring Nation.- 196 p., Sultanate of Oman (Min. of Information and Culture). ARGYLE, E.W. (1954): The Ancient Dhow.- Seabreeze, New Ser., XVIII: 262-5. LE BARON BOWEN, R. (1949): Arab Dhows of Eastern Arabia.- Rehoboth, Mass. E Carvalho, F. da Piedade (2014): Os Dhow do Zanzibar: A técnica de construção de uma antiga embarcação de origem árabe e o seu papel socioeconómico na actualidade.- Cadernos de Estudos Africanos, 27(6): 149-170. DOI: 10.4000/cea.1535. CHETHAM, M. (1950): Dhows in East Africa.- Country Life, CVIII: 1803-7. E De Leeuwe, R. (2004): Seascape and Sailing Ships of the Swahili Shores.- MA Thesis: 123 p., Leiden (University of Leiden). K De Leeuwe, R. (2005): Constructing Sailing Ships on the Swahili Shores.- Azania: Archaeological Research in Africa, 40(1): 107-113. K De Leeuwe, R. (2006): Swahili Ships in Oceanic Perspective.- Sails of History: Citizens of the Sea, ZIFF Journal No. 3: 45-52, http://www.swahiliweb.net/ziff_journal_3_files/ziff2006-07.pdf K Ennion, H. (1963): Along the Shores of the Gulf of Oman.- Country Life, CXXXIII: 1265-6. ‘FULAHIN’ (1928): Coasting East Africa by Dhow.- Blue Peter, V: 449-52. B FALCK, W.E. (2013): Boote und Bootsbau in Tansania, Teil 1: Dauen und Einbäume in Dar-es-Salaam.- Das Logbuch, 49(1): 27-30, Köln (AK Historischer Schiffbau). B FALCK, W.E. (2013): Boote und Bootsbau in Tansania, Teil 2: Bootsbau auf Sansibar.- Das Logbuch, 49(2): 62-65, Köln (AK Historischer Schiffbau). B FALCK, W.E. (2014): Boats and Boatbuilding in Tanzania (Dar-es-Salaam and Sansibar).- Int. J. Nautical Archaeology, 43(1): 162–173. GILBERT, E.O. (1997): The Zanzibar Dhow Trade. An Informal Economy on the East African Coast, 1860-1964.- PhD Dissertation: 340 p., Boston (Boston University). B HAWKINS, C.W. (1977): The Dhow – an illustrated history of the Dhow and its World.- 143 p., Lymington (Nautical Publishing Co.). HORNELL, J. (1941): The sea-going mtepe and dau of the Lamu Archipelago.- The Mariner’s Mirror, 27: 54-68. B HOWARTH, D. (1977): Dhows.- 159 p., London (Quartet Books Ltd.). E Issa, A.A. (2006): Dhows and Epidemics in the Indian Ocean Ports.- Sails of History: Citizens of the Sea, ZIFF Journal No. 3: 63-70, http://www.swahiliweb.net/ziff_journal_3_files/ ziff2006-09.pdf B JEWELL, J.H.A. (19762😞 Dhows at Mombasa.- 103 p., Nairobi (East African Publ. Ho.). B MONDFELD, W. (1979): Die Arabische Dau.- 93 p., Bielefeld (Verlag Delius, Klasing & Co.). MOORE, Sir A. (1940): Notes on Dhows.- The Mariner’s Mirror, 26(2): 205-13. SASSOON, C. (1970): The Dhows of Dar es Salaam.- Tanzania Notes and Records, 71:185-199. SHERIFF, A. (2010): Dhow Cultures of the Indian Ocean. Cosmopolitanism, Commerce and Islam.- XV+351 p. SPARKS, W. (1909/10): A Muscat Dhow.- Yachting Monthly, VIII: 263. SULIVAN, G.L. (1873): Dhow Chasing in Zanzibar Waters and on the Eastern Coast of Africa. Narrative of Five Years’ Experiences in the Suppression of the Slave Trade.- X+453 p. VILLIERS, A.J. (1940): Sons of Sindbad – An Account of Sailing with the Arabs in their Dhows.- Villiers, A.J. (1954): Passage in a Red Sea Dhow.- The Mariner’s Mirror, 40: 171-82. Villiers, A.J. (1961): Vanishing Ships – Arab Dhows.- British Petroleum Shield, 5: 6-8. VOSMER, T. (1993): The Omani Dhow Recording Project: Sultanate of Oman.- Indian Ocean Review, 6(2): 18–21, Perth. E VOSMER, T. (1997): Indigenous Fishing Craft of Oman.- Internat. J. Nautical Archaeol., 26(3): 217-235. E VOSMER, T.A., MARGARIT, R.A., TILLEY, A.F. (1992): A Survey of Traditional Vessels of the Sultanate of Oman. The Omani Dhow Recording Project. Field Reasearch 1992.- Department of Maritime Archaeology, Western Australian Maritime Museum, Report No. 69: 80 p. K WEISMANN, N. (1994): Der Beden-Safar – Eine Rekonstruktion nach Unterlagen von Admiral Pâris.- Das Logbuch, 30(3): 160-67. K WEISMANN, N. (1995): Ein Fischer-Beden in Qurm (Sultanat Oman).- Das Logbuch, 31(4): 175-82. K WEISMANN, N. (1996): Der Beden-Seyad – Ein Fischerboot des Omans im letzten Jahrhundert.- Das Logbuch, 32(4): 175-80. E WEISMANN, N. (1998): The Cargo-Beden Al-Khammam.- Internat. J. Nautical Archaeol., 27(3):237-257. E WEISMANN, N., STAPLES, E., GHIDONI, A., VOSMER, T., DZIAMSKI, P., HAAR, L. (2014): The Battīl and Zārūqah of Musandam, Oman.- Int. J. Nautical Archaeol., 43(2): 413–435. B WIEBECK, E., WINKLER, H. (2000): Segler im Monsun. Die Dau am Indischen Ozean.- 130 p., Rostock (Neuer Hochschulschriftenverlag). WISEMAN, W.F (1994): Modeling a Ninth-Century Arab Dhow.- Nautical Res. J., 40: 5-17. B YA’QUB, Y. Al-Hiji (2001): The Art of Dhow-building in Kuwait.- 164 p., London (The London Centre of Arab Studies). And an on-line resource: https://www.maritima-et-mechanika.org/maritime/tanzania/tanzania.html

The notorious on-line auction houses have 'shops' that sell scalpel blades where the'best before'-date of the sterilisation has expired so the medics can't use them anymore. Boxes of 100 tend to by quite cheap. The same 'shops' also offer heavier handles for the standard blades. Keep in mind that such scalpels are not designed for lateral forces ... These micro-scalpels look interesting, have to look for a European source ...

These are called 'scroll-chucks' because the bottom part of the body has a spiral milled into it in which the 'teeth' of the jaws run. Of course, swarf tends to get into the spiral and can block the jaws. It's worse with wood dust, as this soakes up the oil and forms a tough mass. Once you have taken out the jaws, you can take a toothpick and while turning the chuck you run it through the spiral inside-out, which pushes the swarf out of the spiral. Do this with each edge of the spiral, i.e. two passes.

Only useful for larger scales, I suppose, but jewellers also have a variety with stepped round jaws instead of tapered ones. Like for all tools YGWPF (you get what you pay for) - buying the m on-line can be a hit an miss, the jaws may not perfectly round and only rather roughly ground. Watch out for well-kept antique ones ...

Good luck with your shop resolutions 😉

Not sure what 'non-slip shelf-lining' is. Is this something you put onto the wall-brackets to preven glass-shelves from moving? I personally probably would have made myself a clamp to tie down the material to be cut, similar to what you have on those full-size miter-saws. I have such miter-box, but tend to go for high-tech solutions (lathe) in such cases 😁

I think one has to distinguish between the rake at the design stage and adjusting the rake on an existing boat/ship. As a matter of fact rake seems to be largely a question of fashion, for instance up to the 1840s ships were designed largely vertical mast and then with considerable rake (perhaps to give the impression of speed at the dawning age of clipper ships), while at the turn to the 20th century masts were essentially vertical again. On the other hand, the centre of effort for a given sail will move differently, for a nearly vertical mast compared with a raked mast. I wonder, how important that still is when the ship works in the sea. As observed above the rake is primarily a knob for tuning an existing sail-plan/hull combination or correcting a ship's behaviour. On large sailing ships with their proportionally small rudder surface compared to modern dinghies and yachts, the 'wheather helm' may have been less important and most of the balancing would be done with the distribution of sails set.

Thanks gentlemen for your as always encouraging comments! *************************************************************** 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

This is exactly what my plan would have been. Thanks for confirming it.

How did you make the slot for the sawblade, as on the KS230 one cannot raise or lower the blade?

It seems that number on the spools is not tex, but Tkt (= ticket number) or Nm. Nm is the kind of the inverse of tex. Here is a useful converter for the different measures: https://texelle.com/en/count-converter/. Effectively the formula for converting Nm into tex is: tex = 1000 / Nm. However, normally the Nm is followed by an indication of the number of ply, how many individual threads there are in a sewing yarn, e.g. Nm 100/2 means that there are two threads of Nm 100 in the yarn, meaning that the weight per lengths and the thickness doubles. I have rearranged the above table (for one-ply threads): As Gütermann Sew-All is probably two-ply, e.g. Nm 100/2 has a diameter of roughly 2 x 0.1 mm = 0.2 mm, which now tallies with your measurements. I use the same method as you, putting say 20 windings of my shop-made rope around the shaft of a drill, measuring the total length of the windings with a vernier caliper and dividing the length by 20 to give the diameter.

The 'diameter' of a thread or rope is difficult to define and measure, as it changes its shape and diameter under strain. That's why other measures were deviced, such as as how much is the weight (in grams) of 1,000 meters of thread, which is the defintion of 'tex'. Year ago I made myself a conversion formula for MS Excel based on the average density of polyester and the assumption that the thread forms a perfect cylinder, viz Ø [mm] = =SQRT(tex/(1,38*1000*100*PI()))*10*2. This formula then gives these rough diameters for Gütermann Mara:

Looking at the image, I more inclined to think that the there hinges/pintels under the overhang of the stern and underneath the wheelhouse, just inside the wall. This explains why the hole for the tiller in the rear wall can be so small. There would be minimal movement at this point.

Somehow I imagined that the axes of the rudders would be just behind the forward edge of the rudder-post. However, if the axes were further forward and under the wheelhouse, there could be indeed a support of the tiller arm inside the wheelhouse. This makes perfect sense and the strain on the rudder post would not be torsion, but bending.

Exactly, that seem to be somewhat iffy from an engineering point of view, when I looked at the image last night and I waited to see, whether someone would come up with real evidence. Are the tiller arms connected, as is done on modern catamarans?