EdT

1:60 HMS Naiad 1797 Part 2 –Basic Drafts I hope the next two parts, which are text heavy, will not be a turn-off to those not too interested in drafting. For me drawing is intertwined with the actual modeling, and so, I wanted to give it proportionate coverage. I will also add that the drafting process helped me tremendously in understanding the construction of the ship and in giving insights valuable later in construction. For those less interested in this, it may be heavy going, but fear not, by part 4 we will be into construction – and more pictures. In this first part I will cover the steps I went through to reproduce a 2D CAD version of the original Admiralty lines draft. This is the basic drawing and the starting point for everything else. Many additional drawings have been made or will be made and will be discussed later. For those unfamiliar with the terminology, the lines drawing includes a sheer plan, which is actually not a plan by modern definition, but a side elevation of the external features of the ship and several important longitudinal lines. I will usually refer to this direction of view as the “sheer plane.” The lines draft also includes a plan view (from above) of key longitudinal lines called the half-breadth plan, which in addition, shows locations of cant frames and hawse timbers. The body plan to the left is a split elevation view, the left side a view from aft and the right side from forward. The body plan shows the shapes of the hull at each joint line (sometimes called frame lines or stations), plus a number of important reference lines. Joint lines represent vertical planes, perpendicular to the keel at the joint line of the two frames that are fastened together to make up a main frame bend. I will use the term “joint lines” to refer to the main frame joint lines shown on the original draft, and the term “frame lines” to refer to all the frame lines, including the ones in between not shown on the original drawings. A scan of the original Naiad lines draft is shown below. After completion of the lines draft, other basic drawings were made by the surveyors. The profile drawing is a view of the sheer plane (side elevation) along the middle line of the ship, showing internal structure, the keel assembly and internal deck details. The framing drawing, or “disposition of frames” is a view of the sheer plane showing all the frames and each of their timber parts, called floors, futtocks and toptimbers. Below are the actual profile and framing drafts on my real (non-computerized) drafting board. These original drafts could be used for model making, but there are some issues to be considered – one specific to my model and at least a few that are more general. The scale of these drafts is 1:48. My model is 1:60 - an obvious issue. Another issue is that if the basic drawings are used, then lofting will be done manually, or at least semi-manually. With the original drawings it is less easy to make the drawing fit the construction process needs. I will discuss this more later. The last relates to potential for distortion or other inaccuracies in these very old drawings, which I will discuss below. I made the Naiad drawings using 2D CAD, with an old Windows application, Visio Tech 4.1, which I have used for many years. It is dated, lacks some features, but was quite adequate. There are many advantages to CAD: It can be very fast for some tasks. It produces very high quality drawings with lines down to 1 pixel wide. It is easy to move views and objects around for different purposes. It excels at quickly expanding canted surfaces to their true view for lofting. It is easy to print off copies and make revisions. Multiple copies of patterns are easily printed to paste to wood blanks, use as assembly patterns, or to make alignment gauges. It’s easy to add a lot of legible text to drawings and color can be used and printed. All the work is done in actual measurements so conversion is minimized and prints for different scales can be made quite easily. I am not going to go through this drafting, step by step, but only highlight some areas. I may go deeper on some of the lofting, but will save that until discussing its use in actual construction. The Lines Draft The first steps in making the CAD lines draft are quite easy. The top of keel is drawn first and it’s pretty hard to miss with a straight horizontal line. Perpendicular vertical lines at each end of the gun deck, known as the aft perpendicular (AP) and fore perpendicular (FP), are easy because the length of the deck is stated in feet and inches on the draft. The next step, location of the midship perpendicular or dead flat (DF) requires the first real measurement to be taken from the draft. This first measurement introduces the issue of drawing error and measurement error. Error in these old drafts can result from measurement error when they were made, distortion of the originals over time, line blurring, reprographic error and the practice of using wider pen width for some lines. To determine the accuracy of the lines draft – the most important drawing - I first checked the accuracy of the scale at the bottom of the drawing at the right, center and left of the sheet, then checked horizontal measurements on the drawing against dimensions stated on the drawing. This was done for example, by measuring a length on the bottom scale in mm, converting it, then comparing. The results indicated an error range of from .16 % to .4% depending on where dimensions were taken. For all but the largest dimensions I concluded this level of error was inconsequential for modeling purposes. Accuracy of the draft vertically could not be easily checked, so I decided to ignore it given the small horizontal error. So, the dead flat was able to be located reasonably well. The next critical dimension to be measured was room and space. Room and space is the distance between each frame line (including intermediate frames) or one-half the distance between (most of) the joint lines – the lines at the center of the main frame bends. Used in conjunction with the specified fore and aft sidings of the timbers it assured a defined ventilation space between frames – critical in these rot-prone ships – and critical in the model for proper location of frames and frame lines. I measured this a number of ways before fixing the value at 29 inches. Once all these basic construction lines were drawn, I essentially followed the process described in The Shipbuilders Repository 1788 for constructing the sheer draft. Although the language is ancient and sometimes difficult, this book lays down how designers actually constructed these drafts, in detail – the section on the sheer plan alone is 26 pages. The book was an instructional text for aspiring surveyors and shipwrights – and unknowingly, for at least one 21st century model draftsman/builder. Below is a very reduced image of the resulting Naiad CAD Sheer Draft. The Body Plan The original body plan shows the shape of the hull at each joint line, and is therefore a critical design drawing. All the lines are “moulded” breadths, that is, they are to the outside of the frames, not the outside of the planking. To produce an accurate model, the body plan needs to be reproduced as accurately as possible. Historically, after the body plan was drafted, it was used to produce the waterlines, ribband lines and some other key longitudinal curves that make up the half breadth plan. These curves were then checked for fairness and, if necessary, the body plan was adjusted to yield fair longitudinal curves. Even though the original draft body plan was checked and adjusted by the designer, this process was followed for the CAD plans. Original body plans were drafted using circular arc segments, called sweeps. By varying the diameter and center of these arcs along the length of the ship, the final hull profile was developed. The resulting underwater shape determined key qualities of the ship – sailing characteristics, hold capacity, stability, etc. During the 18th Century, the underwater bodies of this type of ship were drawn with three sweeps, which are pointed out below on the original Naiad body plan, along with some other information, in red For those not familiar with this construction, I will try to describe it. First, British ships had a straight vertical section at the extreme breadth of the hull which ran between two dotted lines called the “heights of breadth. This straight section was larger at midship and decreased toward the ends. It is described by dotted curved lines in the sheer plan and on the body plan. The lower breadth sweep for each joint line started at the bottom of this section and swung down, with its center at points on a horizontal line through the bottom height of breadth. This formed the hull shape just below the height of breadth. The designer set the diameters of these sweeps. Starting at a horizontal line a short distance above the top of keel, the floor sweeps were swung upward with their centers on a rising line shown in the above drawing. This rising line was based on curves drawn by the designer on the sheer plan. On the sheer plan the vertical rising line is the wide u-shaped curve in the center of the lower hull. Its horizontal counterpart is an inverted u at the bottom of the half breadth plan. These curves and the diameters of the floor sweeps were also designer decisions. A third sweep, called the reconciling sweep connected these two tangentially. Its curvature was set by the designer, often by setting a point on the 4th diagonal, through which the arc would be drawn. Finally, a concave curve from the lower end of the floor sweep to the rabbet of the keel would complete the underwater body. Historically, French frigates generally seem to have had smaller diameter breadth and floor sweeps and large diameter, long, reconciling sweeps. This made for a sleeker hull, but a smaller hold. British ships generally had larger diameter breadth and floor sweeps, yielding more hull volume. The upper breadth sweeps were generally all the same diameter and were drawn upwards from the top of the height of breadth. A reverse curve would take this to the top of the side. If I were recreating this drawing manually, I would do so with these circular arcs. The Naiad draft has virtually all the information on it to do this. However, Visio does not have good tools for creating tangential reconciling sweeps, so the arcs, plus spline curve functions, were used to make the CAD Body plan. This was then carefully checked against the original by printing the CAD plan at 1:48 on transparency film, laying it over the draft, marking any deviations, then fixing the body plan and repeating this process until both were virtually identical. Also, points along diagonals and waterlines were measured from the original and checked on the CAD version. A version of the CAD Naiad body plan is shown below. At this stage, CAD versions of two parts of the lines draft were complete and ready to be used for the next stages of the drafting process, which will be described in the next part. Ed Tosti 2013 Copyright Edward J Tosti

1:60 HMS Naiad 1797 Part 1 – Introduction After completion of the 1:96 Victory model (see MSW Scratch Build Logs), which is now safely confined to its case, I wanted to begin a new project, and so, after some research and consideration I have begun work on HMS Naiad, a 38 gun Frigate of the Royal Navy, launched in 1797. Naiad is a much smaller ship than the 100 gun Victory and more recent by over 30 years, but that was a mere split second of time considering the glacial pace of change in the British Admiralty. So, generally speaking, Naiad and Victory were contemporaries. Naiad was one of many ships built in response to the crisis following the French Revolution. Below is a picture showing the state of the modeling effort so far. This picture was taken in mid-August, 2010. The forward framing has been erected back past mid-ship and the square framing forward of the aft cant frames is about to begin. This project has been underway for about eleven months now. To begin these notes I would like to go back to October 2009, when the visible progress consisted of three Admiralty drawings and a stack of reference books on my desk, and start the discussion there, at the time Naiad was considered as the subject. Startup There were several goals I had in mind for the new project. Because Victory models are so common, I wanted to build something much less so this time. I wanted something less complicated because I wanted to model the full original framing and wasn’t sure how long that would take, especially for a very large ship, and for a first try at this. At the same time I wanted a scale that would produce a final model of manageable size, one that could sit nicely on a table. I have an ongoing interest in the history of the French Revolutionary and Napoleonic periods and wanted to stay in that timeframe. Finally, I wanted to engage in the full shipbuilding process, starting with basic drafting, through lofting, and finally, construction. This approach gave me considerable latitude in selection of a subject, since availability of model drawings was not an issue. To me that was a plus. I had thought about Naiad several years ago and actually ordered the three available drafts from the National Maritime Museum at that time. Also, a few years ago I started on some drafts for a possible model of Diana, based on David White’s book, The Frigate Diana, in the Anatomy of a Ship series. After reading and digesting Robert Gardiner’s great books on British frigates (The First Frigates, The Heavy Frigate, Frigates of the Napoleonic Wars) and after poring through David Lyon’s, The Sailing Navy List to see what other drawings were available, I settled on Naiad, a typical British Fifth Rate, a 38 gun, 18 pounder frigate of the desired period. Naiad History Naiad was part of a major build up of British Naval strength in response to wars that began in the aftermath of the French Revolution, wars that became more threatening to British interests as French victories on the continent mounted, even before Napoleon. Design for the Naiad was proposed by Sir William Rule, surveyor, in 1795. She was built by Hill and Mellish, at Limehouse, and launched in 1797. Several ships were designed at this time in response to requests for larger frigates and also to address naval officers’ demands for ships with improved sailing qualities – specifically ships “more like the French,” which many believed to be superior. Naval officers were popular politically, and indeed, a number were members of Parliament, so the surveyors, grudgingly, I suspect, did their best – to a point. Some ships were directly copied from French captures, and some like Naiad, made some compromises, but still retained qualities important to Britain’s particular strategic needs – large holds to support provisioning for long cruises, seaworthiness and structural strength. Naiad would outlive the short infatuation with French designs. Below is a scan of the Admiralty Draft of the sheer plan, and half breadth plan for Naiad. This drawing is dated September 1795 and signed by Sir William Rule. Naiad was a “one-off” design, the only ship of her class. However, she was a close descendent, in fact what appears to be only a stretched version, of Rule’s earlier 36 gun Amazon Class (Amazon 1795, Emerald 1795). And she had descendents in Rule’s 1796 Class of 38’s, also under the Amazon name and 3 feet longer (Amazon 1799, Hussar 1799). Naiad was fast in a strong wind, less so in calmer winds, given to pitching, but could handle six months provisions easily. All these ships had their idiosyncrasies, and all the early 38’s had some sailing problems, generally related to too many guns on too short a gun deck. Nonetheless, Naiad was a serviceable ship and had a long and successful career. Naiad is best known for her role at Trafalgar in 1805. She was one of four frigates attached to Nelson’s fleet (Naiad, Euryalus, Phoebe, Sirius). In the hours before the battle these ships observed and shadowed the French and Spanish as they emerged from Cadiz. The chain of frigates signaled the enemy movement to Nelson, in the flagship HMS Victory with the main fleet. The frigates did not join the battle line, but in the stormy aftermath of the battle, Naiad took HMS Belleisle, a battered, dismasted 74, into tow and brought her safely into Gibraltar three days later. Naiad with Belleisle entering Gibraltar During the wars with France, Naiad captured or helped capture several prizes. She was eventually sold out of the Navy and ended her days in other service 1898. Except for Victory, she survived longer than any other Trafalgar veteran. This was a very long lifetime for one of these ships. Naiad Specifications Naiad’s principle specifications were as follows: Length of the Gun Deck, 147’ 0” Length of the keel for tonnage, 122’ 8” Extreme Breadth, 39’ 5” Moulded Breadth, 38’ 9” Depth in the hold, 13’9” Tonnage, 1014 Guns on the Upper Deck, 28 18 pounders Guns on the Quarterdeck, 8 9 pounders and 4 32 pounder carronades Guns on the forecastle, 4 9 pounders and 4 32 pounder carronades The Model Project The model will be a 1:60 fully framed replication of the original ship. The frames will be chocked. Futtocks will decrease in siding and molded breadth as they progress upwards, based on contemporary scantling information. Spacing between futtocks and spacing of frames will follow the Admiralty Disposition of Frames Draft. The extent of planking or additional detailing has not yet been decided. It is unlikely that the model will be rigged. All the framing will be Swiss Pear with some minor use of heartwood cherry where some contrast is desired, for example in the fillings between floors and lower futtocks. European boxwood will be used for topside planking and at least some of the detailing. Castello may be used for some interior framing. The model is being built in the upright position, without full body framing jigs. “Horning” of the frames is being done with squares and profile gauges, squared up from a fully detailed plan drawing, laminated on top of the building board. . This level of modeling will be a new challenge for me, and I hope not too many compromises will be made. Progress The project began in October 2009, while the Victory model was in its last throes of construction. The first task involved preparation of 2D CAD versions of the Admiralty Drafts. Once the CAD Drafts of the Sheer Plan, Body Plan and Half Breadth Plans were completed and thoroughly checked against the originals, substantial information, additional lines, scantling information, and new views were added. Much of this information would be needed to complete the CAD lofting of all frames and timbers. Construction started in January 2010, with fabrication of the building board, some measuring tools, board fixtures and a clamping jig for frame assembly. The first parts of the keel were assembled and laid on the board on January 19. Here is a picture taken right after that important event. With all this background out of the way, the remainder of this series will focus on the actual model work. In it I would like to focus not only on the visual construction progress, but also on two aspects that give me a lot of satisfaction from this craft, and will, I hope be interesting to others. The first is the relationship between drafting and construction, specifically, how drawings were developed and applied to support the specific modeling processes. Second are processes themselves. I like to explore processes and get to one that works for me, and that might work for others. I do not advocate any of these methods or criticize any other. I will merely describe what I did, being candid about pluses and minuses. In the next part I will describe the CAD drafting of the basic views of the lines draft. One down, 175 to go! Ed Tosti 2010 Copyright Edward J. Tosti

Welcome back. We have a lot of work to do. Fortunately I have all the Naiad posts saved as Word files and all the associated images, so I will be putting up the entire 176 parts as soon as I can. The model is approaching completion, so I do not expect more perhaps 10-12 new posts, but there has been enough interest in the old posts to make the effort worthwhile. We will all need to be showing a lot of patience for awhile. I will also opening a topic in the book section for "The Naiad Frigate - Volume I. There are some content updates I want to share there. I will also be reposting the 1:96 Victory Build log, but that will be taking a back seat to Naiad for awahile. Cheers, Ed