The first step is laying out a set of reference lines to use in forming the final shape. This is the first place to make a significant error (been there, done that, got the firewood to prove it). If you carve to a wrongly placed set of reference lines you can find yourself "running out of wood" somewhere along the line. If you visualize the final shape as a kind of phantom hull lurking inside that block, to be uncovered by carving away. You want that phantom to be in the middle, so that there is roughly an even amount of wood to be removed all around. Since you are carving from the outside in, if you place your patterns incorrectly you will be defining a phantom that is too high, or too low, or cocked at an angle (my favorite mistake) and there won't be enough wood left around it to produce the proper shape.
To draw these lines I prefer the Micron Pigma line of drawing pens that are sold in most art supply stores. These lay a very fine line with little or now pressure required. To position the lines you will need three things: a flat surface, a clamp or cradle to hold the block upside down, and a simple surface gauge. The flat surface can be any table or workbench. I find it is best to make a special clamp to hold the hull rather than jury-rigging something from C clamps or carpenter's clamps. The clamp should be capable of holding the hull inverted, on the flat surface, with the waterline horizontal. The surface gauge is just a block with a vertical piece of wood to which one of the pens can be clamped with a miniature C clamp.
The first line to draw is the centerline, which will run down the deck and along the keel line. A flexible plastic ruler helps here. When you have the centerline drawn all around the hull, check against the plan (top) view with calipers to make sure it is truly centered. Place the hull in the clamp and sight both stem and stern along the tabletop. The lines should be vertical; if they aren't, you have the keel line offset from the deck centerline. Sand the errant line gently away and redraw.
Now the most important line, which is the load water line (LWL). Lay the block on the profile (side) view, position so there appears to be the same amount of excess top and bottom, and mark the LWL on the stem and stern. Put the hull inverted in the clamp, and clamp the marking pen on the surface gauge at about the height of the LWL off the table. By a combination of rocking the hull in the clamp and adjusting the height of the marking pen, arrange things so that a) both the stem and the stern marks are the same height above the table and b) the pen is at that height. Then gently draw the LWL by running the surface gauge around the hull. Don't worry if you don't get a continuous line; you can fill in the gaps using the flexible ruler. Sight both stem and stern; the centerlines and waterline should be sitting nicely at right angles to each other. (Stopping periodically to admire one's work is allowed and even encouraged :-))
Now check the position of the LWL against the profile drawing with calipers. At various points along the plan, set the calipers to the vertical distance from the LWL to the sheer (deck) line. Then go to the same place on the hull and make sure that there is wood to spare above the sheer line. Perform the same checks with the lower profile line. As before, if it doesn't work out, erase the LWL with a little light sanding and redraw per instructions above.
Before we get to the last set of reference lines I have to explain the way, in this technique, a hull is formed.
In the technique I am describing, a hull is defined by (usually) three "master sections." One of these defines the main or amidships body, another the "heel," or after body, and the third defines the "entry" or the fore part of the hull. All sections between these are derived by a process called "fairing," which generates a smooth transition, free of bumps or hollows, from master section to master section. A carved hull is faired directly on the wood, by a process that is a lot like sculpture. When you do it, particularly for a hull which is of a "certain age," you are very likely duplicating the process the original designer went through, getting you closer to a "true" shape than any set of drawings can.
I said that fairing a hull was like sculpture, and like sculpture is an art, and like all arts no two people will do it the same. Yet after you do a few hulls this way you'll get a feel for it (and never look at a hull the same way again.)
So the final set of reference lines are the placing of the master sections. First you have to pick them out from all the sections shown on the station plan. The amidships section is easy: it's the biggest one. The fore and aft master sections take a bit of study, but for most hulls you can see where the distinctive form of that part of the hull is defined. In any case, it's no big deal if you're off by one station either way.
When you have selected the master sections, mark their fore and aft positions on the deck center line. With calipers transfer the half beams from the plan drawing to again make sure that there is wood to spare on either side of the hull. At each section position, draw a line on the deck at right angles to the center line, then around the hull with the flexible ruler. Sight from the side. The lines running around the hull should be at right angles to the LWL. If not, yeah, yeah, sand off and redraw.
Now you've got a set of reference lines that position that phantom hull right near the middle of the block. Carve away everything that doesn't look like part of a hull and you're done :-)
To carve the hull you'll need the usual Xacto knives, a fairing tool, and a couple of battens. A fairing tool is a long, springy piece of material to which you attach the self- adhesive sandpaper used on small power sanders. A flat-surfaced sanding block is deadly to the fairing process; there ain't no planes on the kind of hull we're talking about :-) Using your fingertips is even worse. For the average (two foot or so) hull a thin, springy, 18" steel ruler is good. Battens are springy pieces of wood, say 1/4" x 1/8" model airplane spruce, used to check fairness and draw sweeping lines.
Make a set of patterns of the master sections. Xerox the plan, fold the copy in half carefully down the centerline, and cut both sides at once. Using a full pattern instead of a half pattern really helps get things symmetric. Glue to file folder card stock and cut out carefully. Make sure the LWL is marked on the pattern.
Draw the plan view on the deck. Don't cut a pattern from the plan -- for (usually) sweeping curves like this you'll never get it right. Instead, lay off the half beam distances for several sections. With pins (or better yet, a helper you don't mind being close to :-)) hold a batten in place to get the sweep of the hull shape and draw along the batten edge. Sight down the deck from stem to stern to check symmetry and if not ... well, you know what to do.
The order of carving and fairing is: amidships master section first, then aft, then fair the after body, then fore master section, then fair the fore body. Other sequences are possible, but they don't seem to give the same "feel" for how the hull is developing.
Carve to the amidships section first. Carve parallel fore and aft, so the middle of the hull looks a bit like a straight tube. Check with the pattern, making sure that you align the LWL on the pattern with the LWL on the hull. As you carve away parts of the reference lines, redraw them with the flexible rule.
Then carve to the aft master section. It's hard to describe how this looks; the closest I can come to it is that you carve at a straight angle from somewhere between the two sections, so it looks like a hull made out of two sheets of cardboard, one straight (the amidships section) and one conical (the aft section). Watch the deck plan so that you don't cut off a diagonal that should be an arc.
Now you are ready to fair the aft body. This is one of those things that is obvious when you watch it being done but tough to put into words. Anyhow, here goes: Put a little spring into your fairing tool so that it forms a gentle arc. Hold it at a 15 deg angle or so to the center line, and sand with a gentle curving motion so that you are forming a compound curve. Go slow. Do a little on one side, then a little on the other. Check by laying a batten along the line a typical plank would take. Sight carefully for bumps or hollows and work out with the fairing tool. As you get used to doing this, you'll see the hull form come up as if by magic, and your eye will be trained to recognize fairness when it sees it. Work it down to the deck line. It's not possible to perform too many checks with the batten :-)
The fore body is carved and faired the same way. If the hull has a "hollow" (concave) entry, like a lot of clipper ships and some yachts, then you may find yourself bending the fairing tool into a convex instead of concave arc.
The last thing to cut is the sheer line. On "yacht like" hulls, this is one of the most critical lines -- get it right and the hull is lovely from almost every angle, get it wrong and the hull never looks quite like a vertical heights from the LWL for several stations, and draw the line with the batten. Check by sticking pins on the line at station points and sighting from for and aft to see that they are at the same height. Carefully carve close to the line and then sand. This is the one point where a sanding block helps; especially the round-ended ones sold by MicroMark. Try to get a sweeping motion in your sanding. When you're almost there, switch to a scraper. Hold a wide Xacto chisel blade in your hand and pull it toward you with the ground bevel edge away from the direction of travel. This will shave a very small amount of wood from the deck. With a little practice you can scrape a sheer line to a really sweet sweep.
And that's it. One day you'll do a hull and it'll be so pretty you won't want to clutter it up with all that fiddely little detail (just kidding).
Well, I seemed to have rambled on an awful lot; as the old line goes,
I regret I didn't have the time to write a shorter message. But I hope
this conveys some of the enthusiasm I have for carving hulls, and
helps you (and a useful discussion) get started.
{William E. Boebert}
My suggestion is to get a picture in your mind of how the hull should look. Study the box art, study the plans. Study the lines and get a rough feel of where the highs and lows should be.
Place the templates in their positions and see how close they fit. Then carefully sand and carve your way down along the entire hull on both sides. Don't concentrate on one area. You can distort it too much.
As you begin to remove wood Keep looking at the templates and the overall hull. Do the lines flow over the hull as you have visualized them? If not, do some more work.
My first model was the Phantom for Model Expo. I followed the templates, but I also made sure the overall feel of the hull was smooth and that both sides were balanced.
You will make mistakes. Learn from them and move on.
(Mike Tavella}
8" shoe makers rasp
small block plane
3/4" Flexicut gouge -(awesome tool!!)
1/2 " wood chisel
The most important fairing tool was a sanding batten. I took 1/32" basswood 1" wide by 24" long, and rubber cemented a piece of 1" finegrit sanding belt to it. I glued two small blocks to the end for handles. This thing faired the hull, and took out the hills and valleys between the template carved areas in no time. It also worked much better than a power sander when I was fairing in the plating on my 40" destroyer hull.
Hope this helps
PS: if you make a gross mistake in the bow or stern, you can cut
off the offending area, and glue and dowel on a new block and
recarve. It gave me the creeps to do it the first time, but it
sure turned out better than just leaving it wrong or trying to
fix with epoxy putty.
{Jay Schantzen}
In the sheer plan, or side elevation, the waterlines appear as lines drawn parallel to the base line (usually the keel rabbet) at regular intervals (such as 1/4", 1/2", etc.) above it. For the lift method of construction, the model and plans should be in the same scale, as the thickness of the wood used for the "layers," or lifts should be equal to the interval between waterlines.
In the half-breadth plan, which represents a view of the hull if the sheer plan
were rotated 90 degrees about the longitudinal (fore and aft) axis of the hull,
the waterlines appear as a series of somewhat concentric curved lines. In
this view, they resemble nothing so much as a topographical chart, showing
elevation lines (which, in effect, is what they are).
{Jim Roberts}
Kirby was an aeronautical engineer, and wrote several articles for MS at about that time. {Jim Roberts}
This follows a couple of criteria. The first is the choice of timber which wants to be totally knot free and stable, in that it should be from a known species that doesn't cup round the heart wood or centre. Cedar, spruce and cypress are three such timbers which are readily available in most parts of the world.
The next criteria is that the timber be dead dry with a very low if negligible water content. Timber will expand greatly in its width but little in the length which doesn't occur so much if the timber is dry or well seasoned. I usually keep timber in my living room where it is warm and dry which accelerates the seasoning considerable. Ideally, one should choose a crown free piece of timber with vertical grain to it. The crown is the centre of the tree and timber is usually cut straight across it. Straight grained pieces can be found either side of the crown and it is these that are cut off the plank and glued up to form a new plank
Jointing the flat surfaces of the boards is most important as the boards should be lightly clamped just enough to squeeze the glue out and not to compress the fibres of the timber. Any board that is warped or twisted to start off with will try to get back to that shape even after it has been dimensioned through a surface planer or jointer so should be discarded at the purchase/acquisition stage.
Hollowing out the hull is important as the thinner the hollow then the less likelihood of the timber warping which in turn will cause splits. I have seen hulls almost as thin a newspaper. Naturally, if the boat is a working model then it has to be as thin as possible to remove as much weight as one can. Every ounce of timber removed from the hull means yet another ounce of lead can be placed on the keel which adds to the stability of the vessel by lowering the centre of gravity to as close the ship's meticentre as possible.
To successfully hollow out a bread and butter hull after first shaping the outside one will employ a decent sized bow calliper set at the thickness required to check that the hollowing process is running true.
The 'Kirby method' as written by him in Model Shipwright is not new as Steve 'pinched' the idea from an old and ancient idea that was years old when he was running round in short pants with a dummy in his mouth. He is a very old friend and will forgive me for saying this of him. For those new to the hobby, please allow me to explain the process.
Looking on the plan drawing of the ship from the deck to the keel one will notice some contour lines that run from stem to stern. These are known as 'waterlines' and are in effect the shape of the hull at that point. they are shown again in the profile or elevation plan of the side of the ship and again in the body or frame plan. With the elevation profile drawing we can see how thick the planks should be and on the plan drawing we can see what shape they have to be. A tracing is taken off the plan drawing and transferred to a plank and the plank then cut to the line. The next plank is done likewise and so on until all the sections are done. the next stage is to rough saw out the middles of each board so each plank overlaps the one below it by ½ to ¾ of an inch. When hollowed, the whole lot is glued together with the glue being the butter and the timber the bread - hence the term. Light clamp pressure should be exerted until the glue just runs out of the joints.
A hull is a devil to clamp as its shape doesn't take kindly to being squashed at the best of times so it is prudent to invert the hull deck side down on a ¾ inch plywood board and lay another about the same dimensions as is the outer side of the hull and then clamp the two together, using as many clamps as one can round the sides to maintain an equal pressure. When the glue has cured then the hull can be removed from the clamps.
I have found excellent results with 'Gorilla' glue which expands a bit during curing and fills all the little gaps up. To apply it one coats just one surface of the joint in a thin film of glue and dampens the other surface with a wet sponge or cloth. The H²O is the final key to the chemical bond and is totally waterproof like Cascamite when cured.
We now trace out the frame shapes from the body plan and transfer them to stiff card to use as shape checkers on the carved hull. A series of upright station lines are copied from the elevation drawing and transferred to the deck so that we know where to place the station card to check for shape. The outside of the hull can now be rough chiselled to the external hull shape. To do this I prefer a gouge than a flat bladed chisel as one has more control over it. The flat chisel comes later for finishing. When nearing the shape use a rasp and coarse carbide paper to sweeten the hull to the templates. If one has a belt sander all the better as this will grind down large chinks of timber in seconds. Wear a face mask that is rated for the appropriate job as dust can kill if too much gets in ones lungs as it cannot be ingested.
All that's left is gouging out the inside to the shape of the outside using the callipers as a guide. The best eyes we have for modelling are not the ones in our head but the ones on the end of our hands as touch tells one more than sight can as we can't always see lumps and bumps but our fingers can. It's the wet paint syndrome. We always have to touch the paint surface to see if what we read on the sign is correct and the paint is actually wet.
That's about all there is to know about bread and butter Kirby style hull construction.
To recap,
I'm currently working on SMUGGLER, a Gloucester clipper-model fishing schooner from 1877. The kit (BlueJacket's) was designed by no less a personage than Erik A. R. Ronnberg, Jr.
I decided early on to carve the solid hull to the inside lines of the planking in order to actually plank the dang thing with proper (and realistic, I'd hoped) belts of planking. Making up the templates from the body plan gave me a deep appreciation for the shape and lines of the vessel. Adjusting the templates to account for the scale 3" thickness of the original schooner's planking taught me so much I'd only bore those reading this post with my "revelations."
Carving the hull down to the inside of the planking, although it only represented a scale 3" (1/16" actual), generated so much waste material (sawdust) that I was staggered by how much had to come off.
Poring over hundreds of photographs in over 30 books on Gloucester and Essex fishing schooners made me believe the hull was planked with quite a number of belts of different width planking, all planks within a given belt being the same width. But what were these widths?
Not wishing to be a nuisance to Erik Ronnberg and respecting his privacy and time, I wrote to five different historical societies, museums, shipbuilding facilities, and libraries seeking this information. All this querying yielded nothing in the way of help or information, other than (in one of life's little ironies) several suggestions that I contact the recognized expert on the subject, Erik Ronnberg.
With "hat in hand" I wrote to him explaining my dilemma. He was very generous and full of pity and sent me a profile and body plan with the belts of planking drawn in and faired.
Cutting the planks on my Preac saw and hanging them on the hull gave me such an appreciation of how it was done full-size, how the lines of the vessel were drawn to create certain handling characteristics, how it all came together so cleverly, made me realize that ship (schooner) design and construction was truly an art and a sublime craft and the only real way to grasp all this was to actually do it. Either full-scale or in miniature, but the key (for me) was to do it on a solid-hull model.
Just an opinion, mind.
{Bob Steinbrunn}
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