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Sultana by SardonicMeow - Model Shipways - Scale 1:64

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Welcome to my Sultana build log.




I plan for my Sultana to deviate from the kit in two significant ways.


First, I will be modeling the 2001 Sultana replica, rather than the 1767 original.  In addition to pictures taken by myself and others, I'll be using the book Schooner Sultana: Building a Chesapeake Legacy by Drew McMullen with photos by Lucian Niemeyer.




The book covers the construction of the 2001 ship with lots of descriptions and photographs.  Best of all, there is an appendix with measurements of many of the main components.  




The second significant deviation is this.




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43 minutes ago, SardonicMeow said:

First, I will be modeling the 2001 Sultana replica, rather than the 1767 original.

I like this idea. I, too, have a Sultana kit in my stash, where it will probably remain forever (unless someone offers me some scratch for it -- hint hint). I didn't like how my hull carving efforts turned out, so I drafted a new set of bulkheads from the plans using the technique described by Edwin Leaf in Ship Modeling from Scratch. Sadly, I didn't like how that hull turned out, either. Oh, well! I hope yours turns out much better!

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My plan, which I hope is not too ambitious, is to make a plank on bulkhead hull.  I have access to a local makerspace with a laser cutter, so I intend to laser cut the pieces.  I'd like to develop a workflow of going from plans to parts that I can apply to future projects.


Let's look at the plans of the Sultana.


Follow this link to see the original plans on the National Maritime Museum website.  I suspect most visitors to MSW are familiar with the circumstances of the Royal Navy acquiring and recording the lines of the Sultana.


Who exactly did the work of recording the plans, at Mr Randall's dock in 1768?  Was it this guy whose name is in the corner?  Adam Hayes?




You probably know how the plans were cleaned up and recorded by Howard Chapelle in 1935.  The Chapelle plans are reproduced on the end papers of the Schooner Sultana book.


In white on orange...  Thanks guys.




Scan, invert colors, levels, convert to grayscale, more levels, crop into separate files.




That's better.




What stands out about the plans is how few station lines there are.  Just nine.  Was Mr. Hayes in a rush to meet his mates at the pub that day?


Often, the plans of a larger ship will have 20 or more stations, and a modeler can just choose all or some, make bulkheads directly from those lines, and be done with it.  But nine isn't enough.  Based on my one and only plank on bulkhead experience, I want more bulkheads.  I want lots of bulkheads.


It's time to find my bulkhead lines.  It's time to go to the drawing board start up the CAD software.


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Step one is to bring the plans into Fusion 360 as canvas objects.  The plans are checked to make sure that all lines are perfectly horizontal / vertical, and that lines in one view match up to the corresponding lines in a different view.  The images have been scaled in the 3D environment to match the scale of the model (1:64 or 1 foot = 3/16").  The 3D origin is at the intersection of the baseline, the centerline, and the forward perpendicular.




A number of construction planes are defined.  Here are the station planes.




And the two water lines plus the load water line.




Planes for the three diagonals are also defined.




And canvas objects for the diagonals are added to the environment.




A final, and very important, construction plane is one which defines the thickness of the false keel.  I plan to use 1/8" thick wood for the false keel and bulkheads.  Converting to metric, that's 3.2mm.  But because I am only building a half hull now, which will be mirrored later, I will set the false keel offset plane to be 1.6mm from the centerline.


With the reference images imported and the construction planes defined, the environment is ready for the hull modeling to start.


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Now I'll create sketches of the various hull curves.


(In the 3D/CAD forum, there is a thread where I worked through this method.  You can check it out if you're interested in more details about the procedure.)


For the topmost line, I will create a curve following one of the bulwark lines on the plan.  To ensure correct placement, I create a construction point at the tip of the bow, which will be used as a starting point for the curve.  A fit point spline is created in a horizontal plane following the curve as viewed from above.




Then the points on the spline are adjusted up or down to fit the curve as viewed from the side and front.


In the picture below, the curve is viewed from the front and back showing how it follows the plan.




Next is a sketch for the rabbet line.  It is composed of several lines and curves.  The sketch is drawn in the false keel thickness offset plane.  The same starting point at the bow is used to start the bow curve, meaning that the bulwarks curve and bow curve intersect at that point.




Here are the two sketches so far.




Now I select the construction plane for station 1, then go to Sketch -> Project/Include -> Intersect and click on the existing lines to find the points where they intersect with the plane.  This is repeated for each station plane.  The intersection points are displayed as purple circles.




Using the intersection points as start and end points, a fit point spline is sketched for each station following the curves on the body plan.




Why all the intersection points?  Later on, I'll be using the loft and rails feature in the Fusion 360 sculpt environment.  Loft creates a surface between two or more curves (profiles).  Rails can be used to adjust the flow of the loft.  However, all rails used in a loft must intersect all profiles.  To make sure all the curves intersect as needed, I find the intersection points first, and draw fit point splines using those intersection points.


Next time, sketching continues.


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The sketching of lines continues with finding intersection points and then sketching fit point splines through those points.  Here are the intersection points for the two waterlines, with the waterline planes visible.




And then the splines.  Drawing the lines is easy -- just a matter of connecting the dots with a little adjustment of the curves at the end.




The same procedure is followed for the load waterline.  But wait...  The intersection points don't seem to match up to the line on the plans.  Is this an error in the plans?





No.  This is because of how sketches work in Fusion 360.  When you start a sketch, you choose the plane on which it will be drawn.  Then Fusion 360 brings you to a view that is tangent to the drawing plane.  Because the load waterline is tilted a little off horizontal, the view isn't directly down onto the plans.  Instead, it's skewed a little, so the view doesn't match up.  The load waterline drawn on the plans is a projection of the hull line down onto a horizontal surface, so to see it correctly, the view needs to be changed so that the viewport is looking directly down.  See the view from directly overhead below.


Those of you with sharp eyes may have noticed that aft-most portions of the load waterline curve don't quite match the line on the plans.  That is an issue with the plans, as the intersection point is correct in the sheer view.  I think it's close enough not to matter much.




Do diagonals work like the load waterline?  Are they projections down onto a horizontal surface?  No, they really do get drawn directly on the tilted planes.




Here are all the lines at this point.




Now it's finally possible to create the hull surfaces.


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In order to establish a good ending shape for the hull, I added one more curve at the stern.  This is a little guesswork since it isn't a line on the plans, but I think the shape is pretty close.




Now the lofting can begin.  I click on "Create Form" to enter the sculpt environment.  Then Create -> Loft.

When I select the start and end curves for the first loft, it looks like this.




From above, it's clear that the shape isn't right when there aren't any rails.




Once the rails are selected, the shape conforms to them.




The surface is constructed in sections by lofting between station lines.




Uh oh.  The loft doesn't work back here.




My solution is to loft this area in two parts.  First, I break the longer station line into two parts.  The top part stops at the same height as where the smaller station line ends.  The remaining half of the station line matches a line along the sternpost.




Then the two pieces are lofted separately.




There is a little gap between the pieces.  The Modify -> Merge Edge operation is used to seal the gap.




I finish the lofting and create a mirror of the surface.  It doesn't look too bad.  The reflection in the aft area has a little wobble in it, showing the isn't quite smooth there, but I can deal with that later.




It's neat, but so what?  How can I use this?


For my next trick, I need a volunteer (or several) from the audience to pick a number between 1 and 200.



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The next thing I need to figure out is the exact placement of the decks and the deck camber.  I bring up the inboard profile image.  Starting a sketch in the centerline plane, I trace the lines along the underside of the planking on each deck.  The lines for the two innermost decks (main deck? and quarter deck?) are very slightly curved.  The other two are just straight lines.  The sketch continues alone the rabbet and back to the start.  I'll be using this sketch for the false keel.  Notches for bulkheads will be added to it later.




The deck camber isn't obvious from the Chapelle plans.  On the Model Shipways plans, there is a diagram showing an arc over a span of 72mm with the highest point of the arc at 2.5mm.  I assume this is the camber at the widest part of the deck, but can be applied overall.




Applying those measurements, I create arcs on the 3D model passing through the start and end points of each deck.




Surfaces are lofted across the arcs.  For the two larger deck sections, the line of the deck along the centerline is used as a rail, because it's curved.  That gives those deck sections a very slight saddle shape.


(This picture makes it look like I'm creating a solar-powered ship. 🙂)




Here are all the surfaces to this point.



Edited by SardonicMeow
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Think you could at least print the frames for the bulkheads.  But it looks the the bow is a bit blunted.  Could be the angle of the previous picture. Would love to see a few more frames in the bow to give the curvature some more context. Hard to visualize without looking at the 3-D CAD presentation on a monitor. 


But it really really neat stuff!!!

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Finally I will start to find the shapes for some bulkheads.  I know that I will want bulkheads at the three points where the deck level changes, so those seem like good ones to start with.


I start by making the inboard profile image visible, since it shows the internal structure.  Via the construction menu, I create an offset plane at the point where the forecastle deck drops down to the main deck.  It's 52.7 mm back from the forward perpendicular.




Next I make the hull and deck surfaces visible.  I select the offset plane and go to Sketch -> Project/Include -> Intersect.  As I move my mouse pointer over the surfaces, anywhere the offset plane intersects with a surface, the intersection curve displays as a red line.  I'll click to select the first intersection curve.




And the one across the deck.




And finally the one on the other side of the hull.




When I click Ok the three curves are saved as a new sketch.




There is some overlap where the deck and hull lines meet.  To edit the sketch any further, I have to break the link between the intersection curves and the surfaces.  I select a curve, then right click and select Break Link.  This is repeated for each curve.  The curves change from purple to blue.




Now I go to Sketch -> Trim.  When trim is active, segments of lines in a sketch that can be trimmed will turn red when the mouse pointer is over them.  I trim off all the overhangs.




And I add a notch 25mm above the baseline.




The first bulkhead is complete.  I can right click on the sketch, choose Export to DXF, and import the shape into laser cutter software.



Of course, I need to add a matching notch to the false keel.


I would also like to add fairing lines to each piece.  The procedure is the same, but I don't need to include the intersection with the deck surface, and there is no notch.


For the other bulkheads at places where the deck level changes, I follow the same procedure.  For the second bulkhead, the hull lines don't quite reach the deck curve.  In this case, I first use Sketch -> Extend to extend the lines, then use Trim to trim any overhang.




I edit the false keel sketch and add notches at the appropriate locations for the three bulkheads I've created so far.




And here's a view of all the sketches defined in this session.  All of these will be exported for use on the laser cutter.





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19 hours ago, Overworked724 said:

I hope you will also consider a laser cutaway for the transom. (Badly needed in this kit!!)

Yes, that's something I hope to do.


13 hours ago, russ said:

Will you include the bulwarks in your bulkhead frames?

Probably not.  The bulwarks are very short -- just a few inches above the deck level in some places.  I think I'll do things like in the practicum: end the hull planking just below the level of the deck, then fit a strip for the bulwarks above it, with another strip on the inside.


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Before I add any more bulkheads, I think it's a good time to cut out the notches for the masts and bowsprit.  The kit-supplied dowels are 6.4mm in diameter for the masts and 5.15mm in diameter for the bowsprit.  Tapering will be required above the deck, but I'm happy to leave them at full diameter within the hull.


I edit the sketch for the false keel.  Rectangles are added with a width equal to the diameter of the dowel, then rotated and moved in position to line up with the masts on the inboard profile image.




A similar procedure is followed for the foremast and bowsprit.




Finally, the Sketch -> Trim tool is used to get rid of the lines that aren't needed.




I hope that little pointy bit at the front won't break.


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Several bulkheads were added at the center of the ship.  Because little to no fairing will be required, no fairing lines were identified for these bulkheads.




And here's another bulkhead in the aft part of the ship.




But maybe there is an opportunity here.  If the bulkhead is positioned appropriately, then I can do this...


And that takes care of making the swivel gun stocks.




The same is done for the other locations with swivel gun stocks.




And just to get an idea of what the final product will look like, I thickened the bulkhead templates to the appropriate thickness.


This is what it looks like so far.  I still need to work on the transom and bulkheads near the bow.





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Hi Peter


I am by no means anywhere close to being anything remotely resembling an expert but I think you may have it a little backwards. You have plenty of bulkheads in the midships area and stern, possibly more than you need as there is very little curve to that part of the hull that you will need to bend the planking around. On the other hand in the bow where the planks are going to have to bend the most you have none at all. If you want the planks on the bow to follow the proper flare you will either need to add additional bulkheads or carve/sand a solid bow block. Even with additional bulkheads you may have to fill it in to assist you in planking. This is a VERY blunt bow with a lot of curve.


Just a thought, like I said I am NOT an expert.

Edited by lmagna
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