
Lieste
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Everything posted by Lieste
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It can be higher than that. The aero forces are the vector sum of lifting and drag forces. Depending on the form, lift can significantly exceed a Cl of 1.0, and drag, - form, skin and vortex can be a significant fraction of lift for the relatively low aspect ratio of a square rig. When stalled and either not lifting well, or acting as a parachute drag becomes the dominant factor, with relatively low lift forces. A backed sail is constrained against the mast, so will not fill to the same form, but otherwise behaves similarly to a filling sail. The overall effect is complex, with the lift from one mast altering the flow over those both up and downstream from it, as well as reducing wake energy for following masts.
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Sailing on the wind, and on a reach is done with the sails lifting, even on square rig. It is *only* when going downwind that sails can only be employed in a stalled drag mode, and sailing speed suffers from the combination of running with the wind, and the lower sail efficiency in this mode. Upwind sailing performance is limited by the bracing angle of the sails, rather than a failure of the sails to lift when the angle of attack is appropriate.
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I routinely print models 'offscale' For minor tweaks in scale, the printability isn't significantly affected, and can just be tweaked to give the appropriate dimension. When upscaling, the detail becomes rather 'soft' and can look oversized if taken too far, but generally there is no limit to the amount of upscaling you can perform if the degree of softness is acceptable. When downscaling fine details can become unprintable 'as is', however if dimensions are mutable, the slicer can add a 'hair' of horizontal expansion to retain printable minor walls, and I routinely print models with an intended scale of 1:72 or 1:100 down to 1:330 with few problems, as well as 1:700 to 1:1000 and 1:2973. It is likely that a model generated explicitly for the target scale might print with a better result - but there is a broad range of printable scales for any single model where it will print, with broadly acceptable results.
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There have been a number of simulations attempted along those lines - Among these are the old "HMS Surprise" applet, a set of notes, plans and a spreadsheet on HMS Southampton (1757), from iirc Richard Braithwaite, and an 'admittedly hacked together' simulation of a 5th rate 'Lively' ish ship in "Painted Ocean", which is still available to download and play with on Twitch.io (the others seem to have fallen by the wayside along the way). There are also some papers which cover approaches to the problem and some of these might ease 're-inventing the wheel' - for example a paper entitled "Application of simulation technology to the performance evaluation of HMS Victory as an exemplar of the ships at the battle of Trafalagar", from the University of Southampton (Jan 2006) is downloadable online, and at a first glance might serve as a point of entry at least. (Though I haven't been able to look over it and crunch numbers/play with dynamic behaviour to see if the model holds water).
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Resin cures in light, so I'd keep it in the bottle when not actually printing. You don't want to find cured resin all over your vat and screen. I'm only using an FDM printer right now, so I don't have experience for how quickly you can create problems for yourself, but I have run a film camera and darkroom and know that light sensitive materials can be ruined by careless handling ~ and here you have expensive and delicate components in close proximity to the resin... plus fumes from the resin are not good to have just lying about without ventilation... put it in the bottle, and save the potential trouble.
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It is also a relatively common FDM 3d printing filament (after PLA it is probably the most commonly seen).
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48pdr cannon
Lieste replied to Thanasis's topic in Discussion for a Ship's Deck Furniture, Guns, boats and other Fittings
Not quite. "The captain of the schooner Terpsicore of eleven guns, five on each side and one in the prow, to which were joined eleven other vessels. The largest of these vessels carry no more than 20 cannons, nor the smallest less than 8. The strongest calibre of these guns is twelve pounds*, some only go up to twenty; while that of the the Turkish guns usually weigh 36 and sometimes even goes up to 48". *This is typical of the American fit of guns for vessels of this type and size. Also the 'up to 20' for a few nearly exactly matches the 18pdr claimed as a valid 'heavy gun' of one of these vessels. Turkish guns, would more normally be found on Turkish ships, and the comparison is to show how small and light the schooners were, not to claim this weapon is fitted to the Terpsicore. I would consider this to support a broadside of 5x 12pdr guns, of a relatively short pattern (7.5ft Blomefield/Armstrong might be suitable if English pattern), and a single 18pdr of 8 or 9ft in the prow. -
Carronades can be found with joint or with trunnions, they also can be found with elevating screw and round breech rings, or with elevating screw and a quoin patch (where the casting engravings were moved as it was a large flat surface, and the trunnion was absent on most naval carronades ~ where the marking would normally be done), or with a simpler button and just a quoin. The addition of the quoin patch to the naval version of the carronade was a consequence of failures of the elevation mechanism with the "as first cast" cast iron housing for the elevation screw, after this was replaced by a brass bushing (similar to the reasoning behind bushing the vent), the wear and resistance to cracking were improved. The Quoin could also be used to give more depression than the elevation screw. As far as I can tell the provision of both was normal for most of the use of naval carronades. The carronades represented on Victory for example have a quoin under their quoin patch, but are also fitted for an elevation screw on the piece (this is missing from the ordnance and carriage though, which looks to be not appropriate for the carronade they are using.
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48pdr cannon
Lieste replied to Thanasis's topic in Discussion for a Ship's Deck Furniture, Guns, boats and other Fittings
Further to the 18pdr... a hypothesis that a handwriting or confusing print font/poor quality reproduction led someone to misreport the 18 as a 48 - which combined with a sub-50 cwt ordnance weight led to a conclusion of a carronade, while the actual pivot gun was nothing more exotic than a Blomefeld 18pdr in 43cwt. Discuss. -
48pdr cannon
Lieste replied to Thanasis's topic in Discussion for a Ship's Deck Furniture, Guns, boats and other Fittings
The diagram doesn't match the ordnance displayed, which is clearly an 1823 18pdr of the British pattern. Length is unclear and the close ups don't include the weight markings to allow inference as to the intended weight and length, but 8ft or 9ft are the common types, at ~38 or 43 cwt. -
48pdr cannon
Lieste replied to Thanasis's topic in Discussion for a Ship's Deck Furniture, Guns, boats and other Fittings
A Gun or carronade of 36 livre would fire a boulet plein of around 18.28kg (gauges appear to average high). (As well as other ammunition; canister, bombe, boulet croix etc) An canon-obusier or obusier of the calibre of 36 livre would share gauges with the gun or carronade, but would fire only canister, bombe or a boulet croix, with a weight of 11.71kg. The distinction 'of the size of' implies a common size, but distinct character. IMO. (The same would apply to the 48livre calibre - but I don't have values for a 48 livre piece - or indeed English calibres (e.g. the 24pdr iron howitzer fires shell and shrapnel and case in the calibre of the 24pdr shot, but does not fire the plain roundshot... while the calibre distinction is more clearly seen with the 5.5" brass howitzers which were in use at it's introduction - common calibre, but not firing the same ammunition). Other nations refer to their Howitzers by the mass of a solid stone projectile assumed for the weapon, though only hollow shot and shell, carcass and canister are supplied. (e.g. the 'roughly 24pdr equivalent' "7 pd Howitzer"), or use an unusual measurement standard to distinguish the lighter ordnance (e.g. poods, vs artillery pounds in Russian service for their unicorns - the pood being raised on the smaller merchantile trade pound). -
48pdr cannon
Lieste replied to Thanasis's topic in Discussion for a Ship's Deck Furniture, Guns, boats and other Fittings
A 24pdr of 48cwt might be an answer to the question, that would be suitable for a smallish schooner, and confusable with larger ordnance. This would also match the image of the 'style of gun' presumed to be associated with your schooner, which was a Blomefeld ordnance of a gun pattern (48cwt is the 9ft pattern) - not the shorter, broader style of a shell gun. -
48pdr cannon
Lieste replied to Thanasis's topic in Discussion for a Ship's Deck Furniture, Guns, boats and other Fittings
Within the same period (and even before) the Carron Company had been supplying 'guns of the new construction' and chambered carronades, with a supply of ammunition which included hollow shot, shell and roundshot. (Boulet croix, bombe, boulet plein in equivalent French nomenclature). These were both supplied by contract to the Ordnance, and made commercially available for export. Carron's ordnance was developed following observation of Howitzers in Ireland during the 1750s. There is no technical limitation precluding an early use of boulets croix, and indeed, the use of this type of ammunition for the obsolescent 36 livre obusier de vaisseau (after filled shell was deemed unsafe for shipboard use after a number of accidents and fires) appears to have been practised. -
48pdr cannon
Lieste replied to Thanasis's topic in Discussion for a Ship's Deck Furniture, Guns, boats and other Fittings
Whiles boulets plein, as you indicate were not made larger than the 50 livre gun (19.4cm bore), and the 36 livre/17cm size was the largest in common use, the boulets croix were available in 27c and 22c sizes, as well as in the gun sizes of 19c, 17c, 16c and 15c. The 27c boulet croix had a mass of 48.3kg, and the 22c boulet croix a mass of 25.79kg. (See Lafay pp67-68) -
48pdr cannon
Lieste replied to Thanasis's topic in Discussion for a Ship's Deck Furniture, Guns, boats and other Fittings
Boulet Croix are not the same as Bombe, and canon-obusier could fire both. -
A source of STLs for 3d printing which might be of use are here: https://www.myminifactory.com/object/3d-print-cannon-crew-for-model-ships-1750-1820-165771 plus some other items he has for medieval and Anglo Dutch period sailors, and some ordnance items. Not sure what his future plans are, but he is quite responsive to reasonable requests if they make sense and fit in with his interests
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According to Boudriot, the spars and yards for the 74 were loaded 'unfinished', just the main (built-up) stick, but not finished with head, gammoning, foot etc that make the finished spar. The fitting of blocks etc is an additional step beyond that.
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Recalling the sales proposals for Carron company 'guns of the new construction' and of carronades for arming the 'coastal villages and towns' with weapons in the 3, 4, 6 or 9lb size range, mounted on a small cart, and supplied with a dozen rounds - I wonder if this might be a local home-defence/militia proposal in similar vein. It would be functional for moving a small weapon on the made streets, messuages and back lanes, without the difficulty of working with horses or oxen in confined spaces and under fire they were unaccustomed to. Absolutely no proof that this is a thing for the Netherlands, but there was a proposal to do so for English coastal towns, and I don't see any reason to assume that there was no pressure/opportunity seen to sell ordnance to manors and parish councils where profit could be taken (sorry)... where the well regulated militia could be established to defend and secure the region against invasion.
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The quoin is wedge shaped. When pushed to the front of the the carriage it is taller under the breech ring, than when drawn to the rear of the carriage. When removed the breech ring would sit on the carriage bed, and (at least for lower deck ports with portcovers) the muzzle should then rest on the upper portsill so that the gun can be securely lashed in place with the port closed. When levelled the gun should be slightly below the mid point of the port (such that the available elevation is around 2x above as below (at least for late C18th and C19th ships (the ports were often sized smaller when carriage elevation was smaller in significantly earlier ships). (E.g. Vasa's light 24s had a maximum elevation from the carriage of around 3.5 degrees, compared to the 'up to ~10' of early C19th ships. The level bore-line should be at the same height as the top of the capsquares - when the gun is quarter hung (at the top of the cheeks when centre hung). The trunnion may be oversized, or the carriage may have too small (or a malformed) cutout for the 'half trunnion' The trucks may be overlarge (though those look at first glance to be okay), or mounted on axles not properly set into the lower edge of the cheeks. The cheeks might be too tall (or the deck too thick above the framing. The Ports may have been cut too low. Some or all of these (or indeed nothing other than elevation set too high). For appearance I would first check that the trunnion is really half-seated in the top of the cheeks. I would then look at taking any excess height from: Shaving just a sliver from the bottom of the truck (also increases the gluing area from a perfect cylinder). Check the axletrees are firmly seated high enough relative to the cheeks (can be harder to fix if they need significant raising). Consider reducing the height of the cheeks (and re cutting the trunnion seat). Look at whether the portsills are suitably arranged, fix if possible, otherwise compensate. Consider sanding any 'highspots' of the deck if it is the 'at fault' component, but this might be difficult to do well. For a levelled gun, you can either use a 'zero quadrant' where the boreline is not elevated, or the Line of Metal, so that the quoin is slightly more withdrawn and the top of muzzle swell and breech ring have the same level.
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Definitions
Lieste replied to Don Case's topic in Building, Framing, Planking and plating a ships hull and deck
Cyphered planks is something I know only from a phrase 'flush beaded or cyphered planks' for the normal 'ceiled' walls of a Parish church vestry - the wooden cladding of a plastered stone wall, to around waist level. It is distinct from an alternative finish for the same 'beaded planks' - which I presume to have a prominent 'beading' rather than a flush treatment. More specific details I don't know. Harris cut is a style of glass engraving (characterised by curved lines meeting as a pointed arch, and crossing adjacent pairs) - often seen in drinking glasses. Look up examples and consider whether it might be relevant to the item described. I am assuming from the combination, that you are looking at decor of the cabins. It could refer also to decorative carving on wooden panelling. -
Deck names
Lieste replied to Don Case's topic in Building, Framing, Planking and plating a ships hull and deck
Yes, that looks about a proper proportion, with the 16 gundeck beams looking to be a significantly heavier scantling, and the 18 upper deck beams being lighter. -
Deck names
Lieste replied to Don Case's topic in Building, Framing, Planking and plating a ships hull and deck
IMO you have an (unarmed, enclosed) Gundeck, and an (armed, exposed) upper deck. As this is a Britsh HMAV. I am surprised that there are only 2/3 beams for these full length decks, and that sounds wrong. (Though as there may be a platform listed for the area of cabins (adding a few extra inches of cabin height by 'stealing' from the gun room below at the aft end of the Gundeck, or perhaps forward where the deck is rounded down to allow the cable to run fair from the Hawse Holes). The 14 might also be reasonable for the QD/Fo'csle, or where there are alternative treatments around openings if this is indeed correct for the Upper deck. By examining the (lowish res) drawing attached it looks as if the number of 'solid black' beam ends is similar if not identical for the two complete decks. -
Deck names
Lieste replied to Don Case's topic in Building, Framing, Planking and plating a ships hull and deck
I would expect (but practice can vary) that the marked items are an Orlop Platform, The Gundeck and the Upper Deck/Weatherdeck. British ships with a full deck at or above the waterline tend to have this deck named Gundeck - this can be armed (as with ships of the line), when the lower gundeck portsills are quite close to the water, or unarmed, with the guns carried on the deck above *usually a weather deck* - as with Frigates and Ship sloops. Purchased ships might differ from purpose built HMAV, but I would look them up following this scheme at first, only changing to another schema if the table of scantlings couldn't be reconciled to it. -
Flags supplied by Amati look to be too big
Lieste replied to DaveBaxt's topic in Masting, rigging and sails
I don't have to hand the scaling for His Majesty's Armed Vessel Bounty, but the equivalent for French service has the Ensign at Beam by 2/3 Beam. This should scale to around 123mm by 82mm (Not saying this is *the* correct size for a vessel in the service of His Brittanic Majesty, but your issued ensign is not larger than the Ensigns flown at the stern of foreign vessels and looks to be not unreasonable). The smaller Ensigns are also carried and can be flown instead if the wind conditions indicate reduced canvas is appropriate (or if the ensign is lost to storm or battle damage, to replace the lost flag).
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