CDR_Ret

I need longer fingernails...

Hi, anaxamander49.
 
I have attempted creating ship plans in Sketchup, Blender, Fusion 360, and DELFTship Free. All of these are open source, have free licenses for hobbyists, or are offered as a free version of the professional software.
 
Sketchup creates surfaces in polygons and there is no utility for creating useful hull plans that provides the information a ship model builder needs (e.g., stations, waterlines, and buttock lines). Also, if you attempt to scale down a full-sized digital model to model size, you risk losing precision in fine details due to the way Sketchup works (points, lines, and polygons simply disappear!).
 
Blender and Fusion 360 have (very) steep learning curves and, again, they don't really lend themselves to creating 2D building plans useful to ship modelers without a lot of fiddling around. While Blender is an amazing program, its developers are continually revising the features and interface, so a casual user never gets up to speed in the program.
 
DELFTship Free, in my opinion, is your best bet for creating useful working ship model plans. The program's 2D plan output shows the hull and expected details in standard profile, body, and plan/halfbreadth views. These views can also be customized to show specific objects and omit others, if desired. The program can export 2D DXF images in polyline format that can be imported into 2D vector graphics software for editing and formatting. In addition, the model surface is a true subsurface object that can be precisely shaped with a customizable control net to match existing 2D plans, if required. Like you, I used the program to reconcile incompatibilities among the three views of an existing set of hull drawings that I have come to believe was an unknown mixture of conjecture and actual measurements. The result was a fair hull that seems to reflect contemporary photos of the ship.
 
If you haven't already, I recommend reading through the many topics within this CAD and 3D Modelling/Drafting Plans with Software forum pertaining to the various 3D software others have attempted to use when creating ship plans, and then draw your own conclusions.
 
If you are having difficulties getting started with DELFTship (the manual isn't very good on work flow or process, just feature capabilities), please contact me or the other members who have used the program. Having a guide can help you past many of the frustrating aspects of this program.
 
Best regards.
 
Terry

Heh. Now if I could actually get to building the model, that would be an accomplishment!
 
Looking forward to seeing how this comes together, Mike.
 
Terry

It would be a convenience to have right- and left-scroll buttons added to the individual photos in the Gallery at the top of the MSW forum page. This way, one doesn't have to exit the photo currently being viewed to look at the next one in the series.
 
Terry

These arrows don't appear for me when I maximise the gallery images....so I can't navigate them - not sure why this is....I wonder if Terry is experiencing this same issue?
hamilton

It would be a convenience to have right- and left-scroll buttons added to the individual photos in the Gallery at the top of the MSW forum page. This way, one doesn't have to exit the photo currently being viewed to look at the next one in the series.
 
Terry

Hi and welcome to my second build, the brigantine “Matthew Turner” from Modellers Shipyard.
 

 

 
I have not yet completed my first build but wanted some variety and experience building a next-level-up model, as it were.
 
A little history about the Matthew Turner: (Taken from Modellers Shipyard website)
 
Launched at Sausalito, California in April 2017 the brigantine Matthew Turner is the largest wooden sailing ship to be built in the San Francisco Bay area in more than 100 years. Built of Douglas Fir and Oregon white oak. The Matthew Turner has a length of 132 feet (40m), a beam of 25feet (7.6m) and a displacement of 175 tons (160 tones)
 
The ship pays homage to the ships namesake, Matthew Turner (June 17, 1825 - February 10, 1909) was an American sea captain, shipbuilder and designer. He constructed 228 vessels, of which 154 were built in the Matthew Turner shipyard in Benicia, California. He built more sailing vessels than any other single shipbuilder in America and can be considered the "grandaddy" of big time wooden shipbuilding in the US Pacific coast.
 
The main inspiration behind building the Matthew Turner was the Turner designed brigantine Galilee, launched in 1891. Galilee spent much of her career as a packet, making swift passages back and forth between San Francisco and South Sea ports. She ended her days on the Sausalito mudflats - Galilee Harbour is named for her - but her stern is preserved at Fort Mason and her stem at Benicia.

This model of Matthew Turner is expertly designed with a keel and bulkhead construction. A unique feature of this kit is that it has fairing laser score lines on the bulkheads to make the fairing accurate and symmetrical. All laser cutting is clean and crisp and all parts and fittings are of the highest quality. The English building instructions provide highly detailed step-by-step descriptions supported by colour photos of the model being built. The model is single layer planked.
 
 
 
Why did I choose this model? Several reasons:
It's a very handsome ship
I have a penchant for sail training ships 
It was from the same manufacturer as the brig Perseverance which I am currently building and I am very happy with the quality of that model.
It is a next-level-up (Lv3) which I felt I needed to undertake before immersing myself in the Gorch Fock (Lv4).
The support from Modellers Shipyard was/is excellent on my current build.
The availability of the 4 DVD set of instructional videos is a huge bonus for this novice builder
Because this ship is so new, there is an endless supply of photos, videos and all sorts of reference material available all over the NET
It was on sale, yesssssssss 🙂
 
 
 


Cant say I like the laser etched deck planking, I rather enjoyed doing my own planking.
 

Notice the fairing lines laser cut into some of the bulkheads. I don't know that it is a particularly unique feature as I seem to recall having read about them previously.
 
 
 


I have noticed that some of the smaller parts like blocks, pulleys and deadeyes are of a much higher quality than say those supplied with the OcCre Gorch Fock.
 

 
So that's the kit and I hope to be setting sail with it in the coming week      
 
For anyone interested in the real deal, here is an excellent starting point from Call of the Sea 

It would be a convenience to have right- and left-scroll buttons added to the individual photos in the Gallery at the top of the MSW forum page. This way, one doesn't have to exit the photo currently being viewed to look at the next one in the series.
 
Terry

Fusion360 is horrible for 2d drawings. Every drawing is based off 3d solid geometry... so you need to create solid things that produce body and sheer lines, a real pain.

Thank you all for your input. It's been very helpful.
I've asked several questions on various MSW forums, and I'm always amazed at how helpful everyone is!

Hi, anaxamander49.
 
I have attempted creating ship plans in Sketchup, Blender, Fusion 360, and DELFTship Free. All of these are open source, have free licenses for hobbyists, or are offered as a free version of the professional software.
 
Sketchup creates surfaces in polygons and there is no utility for creating useful hull plans that provides the information a ship model builder needs (e.g., stations, waterlines, and buttock lines). Also, if you attempt to scale down a full-sized digital model to model size, you risk losing precision in fine details due to the way Sketchup works (points, lines, and polygons simply disappear!).
 
Blender and Fusion 360 have (very) steep learning curves and, again, they don't really lend themselves to creating 2D building plans useful to ship modelers without a lot of fiddling around. While Blender is an amazing program, its developers are continually revising the features and interface, so a casual user never gets up to speed in the program.
 
DELFTship Free, in my opinion, is your best bet for creating useful working ship model plans. The program's 2D plan output shows the hull and expected details in standard profile, body, and plan/halfbreadth views. These views can also be customized to show specific objects and omit others, if desired. The program can export 2D DXF images in polyline format that can be imported into 2D vector graphics software for editing and formatting. In addition, the model surface is a true subsurface object that can be precisely shaped with a customizable control net to match existing 2D plans, if required. Like you, I used the program to reconcile incompatibilities among the three views of an existing set of hull drawings that I have come to believe was an unknown mixture of conjecture and actual measurements. The result was a fair hull that seems to reflect contemporary photos of the ship.
 
If you haven't already, I recommend reading through the many topics within this CAD and 3D Modelling/Drafting Plans with Software forum pertaining to the various 3D software others have attempted to use when creating ship plans, and then draw your own conclusions.
 
If you are having difficulties getting started with DELFTship (the manual isn't very good on work flow or process, just feature capabilities), please contact me or the other members who have used the program. Having a guide can help you past many of the frustrating aspects of this program.
 
Best regards.
 
Terry

Hi, anaxamander49.
 
I have attempted creating ship plans in Sketchup, Blender, Fusion 360, and DELFTship Free. All of these are open source, have free licenses for hobbyists, or are offered as a free version of the professional software.
 
Sketchup creates surfaces in polygons and there is no utility for creating useful hull plans that provides the information a ship model builder needs (e.g., stations, waterlines, and buttock lines). Also, if you attempt to scale down a full-sized digital model to model size, you risk losing precision in fine details due to the way Sketchup works (points, lines, and polygons simply disappear!).
 
Blender and Fusion 360 have (very) steep learning curves and, again, they don't really lend themselves to creating 2D building plans useful to ship modelers without a lot of fiddling around. While Blender is an amazing program, its developers are continually revising the features and interface, so a casual user never gets up to speed in the program.
 
DELFTship Free, in my opinion, is your best bet for creating useful working ship model plans. The program's 2D plan output shows the hull and expected details in standard profile, body, and plan/halfbreadth views. These views can also be customized to show specific objects and omit others, if desired. The program can export 2D DXF images in polyline format that can be imported into 2D vector graphics software for editing and formatting. In addition, the model surface is a true subsurface object that can be precisely shaped with a customizable control net to match existing 2D plans, if required. Like you, I used the program to reconcile incompatibilities among the three views of an existing set of hull drawings that I have come to believe was an unknown mixture of conjecture and actual measurements. The result was a fair hull that seems to reflect contemporary photos of the ship.
 
If you haven't already, I recommend reading through the many topics within this CAD and 3D Modelling/Drafting Plans with Software forum pertaining to the various 3D software others have attempted to use when creating ship plans, and then draw your own conclusions.
 
If you are having difficulties getting started with DELFTship (the manual isn't very good on work flow or process, just feature capabilities), please contact me or the other members who have used the program. Having a guide can help you past many of the frustrating aspects of this program.
 
Best regards.
 
Terry

My two cents, which basically corroborates what has been stated previously ...
 
The following information is abstracted from pages 316 and 317 of The American-built Packets and Freighters of the 1850s: An Illustrated Study of Their Characteristics and Construction by William L. Crothers.
 
In the mid-19th century, the spacing of ladder rungs and stair treads was dictated by the natural step of the average 5-foot, 8-inch man (according to Crothers—a value he never provided!).
 
Vertical ladders for accessing deckhouse roofs had equally-spaced rungs. The distance between the upper rung and the roof surface was the same as between the lower rungs, to avoid creating a surprise and misstep when accessing the roof. The lowest rung was at a variable distance above the deck, but could be a larger step than the space between the other rungs. Stringers were at least 4 inches deep to provide toe room at each rung. If the upper end of a ladder ended at a coaming, the upper rung (or tread) was at the same height as the deck outside the coaming, again to avoid tripping or other surprises due to height differences.
 
Inclined ladders (stairs) had treads that were closer together than vertical ladders. However, all treads were equally spaced—from each other, from the lower deck, and from the upper threshold. This is so the user experienced the same drop and rise whether descending or ascending. The number of treads was determined by the height between decks and the inclination of the stair. As the stair angle from the horizontal decreased (became less steep), the vertical distance between treads decreased, and the width of the treads increased. Again, the reference for these dimensions is the length of an average person’s step or pace, but no absolute value was given.
 
Stairs and ladders were made for the specific location where they served and were not interchangeable.
 
Often the lower ends of the stringers of inclined ladders/stairs were cut plumb with the deck (“dubbed off”) below the lowest tread to eliminate a tripping hazard.
 
While the era Crothers discusses is several centuries after the OP’s interest, I imagine these principles were more or less followed from the earliest times simply due to their practicality.
 
Terry

True. He doesn't have the "Byrnes Trifecta" (table saw, thickness sander, disk sander,) either, but as the saying goes, "He who dies with the most tools, wins!"  

I was asked in another forum to explain the process i used to create deadeyes for the Great Harry in resin. I usually print models that i get from thingiverse.com which saves me having to create my own models. In this case though i did create the deadeyes in fusion 360 through trial and error mostly. I am not very proficient at using fusion 360 but i would recommend anyone who is thinking of using a 3d printer to look at some of the youtube video tutorials and learn from them. Once you have the STL or OBJ file that you want to print on your resin printer then there are a number of things that you need to do to print it correctly. Mainly around scaling and setting up the model correctly on the build plate. I use an anycubic photon s resin printer that can produce a high level of detail. If anyone has some specific questions regarding setting these printers up and printing models efficiently then fire away and i will do my best to explain what i know. If anyone wants to see what these printers are capable of i can attach some photos of models i printed and explain what i did. The attached photo is the deadeyes that i made earlier.

Thanks David.
 
I think everything has been said that can be said. I appreciate everyone's contribution from multiple points of view and I learned a lot, personally.
 
Terry

"Once again into the breach" (Henry V-Shakespeare)
 
Because of the persistent view that a constant-camber deck couldn't produce a fair deck, but one with unfair areas in its surface, and because my last attempt to demonstrate that this was not the case was apparently derived from a non-standard approach to ship design and construction, I decided to experiment and see what the outboard-sheer-line-in approach would produce. I had no preconceived notions on this approach, but it seemed that if the outboard sheer line was fair, then it makes geometrical sense that using constant cambers in attached deck beams would also be fair, since corresponding points on the adjacent beams would fall into a curve parallel to the outboard sheer.
 
Many mentions have been made how constant-cambered decks weren't the case in 16th, 17th, and early-to-mid 18th century ships, and I can understand how that is likely due to the relatively low length-to-beam ratios and quite pronounced sheer lines in those eras. But ships became stretched out in the latter 1700s and through the 19th century, so there was less imperative to hand-tool the deck camber, I would think.
 
So, here goes. Using Sketchup again, I created a generic, non-circular curve in three-space and attached it to a vertical plane that corresponds to the centerline of a fictitious hull. The curve represents the outboard deck sheer of the vessel.

Outboard sheer line in perspective.
 

Plan view of the outboard sheer line.
 

Profile view of the outboard sheer line with the centerline plane behind (looking to port).
 
As before, I created a deck camber edge from a segment of a large circle, then placed its center point on the centerline plane. I also added horizontal and vertical guidelines to ensure each camber template was correctly placed longitudinally and on center. These identify deck beam "stations."

Cambered deck beam template and positioning guides.
 
Next, I dragged the camber template down until its edge intersected the outboard deck edge. This was repeated using duplicate copies of camber templates at each beam station line.

Duplicating camber templates and positioning them at the outboard deck sheer line.
 

Completed deck skeleton.
 
As in the previous example in Post #32 of this topic, I "connected the dots" to create the faces forming the cambered surface. (I deleted the curves on the far side of the plane so I didn't have to create 2 million facets, only 1 million...)

Cambered surface created from the camber templates.
 
 
 
You may see where this is leading. Again, to create the deck surface as confined by the outboard sheer line, I created a "cookie cutter" from the outboard sheer line to intersect with the cambered surface. Sketchup allows you to create cutouts of 3D objects using other objects that intersect the one of interest. The cookie cutter's surface is parallel to the z-or vertical-axis of the model.

Outboard sheer line turned into a cookie cutter.
 
After creating the intersection with the cambered surface, I deleted everything but the surface of interest.

 
Intersection that represents the outboard sheer line in the cambered surface.
 
Deleting the surface outside the outboard sheer line, duplicating the half-surface, mirroring it, and rejoining the two half-surfaces yields a fair, cambered deck. All cambers are the same.

Completed cambered deck surface.
 
Finally, taking a look at the orthogonal profile view of the deck, we can see that, while the centerline sheer is smooth, there is a distinct flattening there in the middle, which probably would not be considered "fair" overall. The longitudinal lines in the deck that could represent deck plank edges are no longer parallel to the centerline sheer. This doesn't indicate a problem in form or function, however.

Profile view of a constant-camber deck created by referencing the outboard deck sheer line.
 
So, while this method of constructing a deck might introduce some unfairness in a deck, it doesn't seem to be a significant problem. Recall that the camber round up was exaggerated in this example. With a camber of only 6 or 8 inches, viewing the flattening evident in the above diagram over a length of several hundred feet would be indiscernible, I think.
 
Snide comments about resorting to digital programs to support one's point aside, I don't see any other way to easily and economically illustrate the concepts we are discussing without otherwise resorting to actual plans of actual ships that were built in a particular way. Then what does that prove, except that it worked in that instance?
 
I can't speak about cambers in the forward areas of a ship departing from a fair sheer because I haven't researched those. If anything, those exceptions probably prove the rule. If someone could present an example of such a case, I would appreciate it so I can visualize that situation. I can't conceive of shipwrights having to create numerous deck beams, all with different cambers in order to provide a fair deck in "ye olde days," but perhaps that was the case. It certainly doesn't make geometrical sense to me.
 
Terry
 
 

Thanks David.
 
I think everything has been said that can be said. I appreciate everyone's contribution from multiple points of view and I learned a lot, personally.
 
Terry

"Once again into the breach" (Henry V-Shakespeare)
 
Because of the persistent view that a constant-camber deck couldn't produce a fair deck, but one with unfair areas in its surface, and because my last attempt to demonstrate that this was not the case was apparently derived from a non-standard approach to ship design and construction, I decided to experiment and see what the outboard-sheer-line-in approach would produce. I had no preconceived notions on this approach, but it seemed that if the outboard sheer line was fair, then it makes geometrical sense that using constant cambers in attached deck beams would also be fair, since corresponding points on the adjacent beams would fall into a curve parallel to the outboard sheer.
 
Many mentions have been made how constant-cambered decks weren't the case in 16th, 17th, and early-to-mid 18th century ships, and I can understand how that is likely due to the relatively low length-to-beam ratios and quite pronounced sheer lines in those eras. But ships became stretched out in the latter 1700s and through the 19th century, so there was less imperative to hand-tool the deck camber, I would think.
 
So, here goes. Using Sketchup again, I created a generic, non-circular curve in three-space and attached it to a vertical plane that corresponds to the centerline of a fictitious hull. The curve represents the outboard deck sheer of the vessel.

Outboard sheer line in perspective.
 

Plan view of the outboard sheer line.
 

Profile view of the outboard sheer line with the centerline plane behind (looking to port).
 
As before, I created a deck camber edge from a segment of a large circle, then placed its center point on the centerline plane. I also added horizontal and vertical guidelines to ensure each camber template was correctly placed longitudinally and on center. These identify deck beam "stations."

Cambered deck beam template and positioning guides.
 
Next, I dragged the camber template down until its edge intersected the outboard deck edge. This was repeated using duplicate copies of camber templates at each beam station line.

Duplicating camber templates and positioning them at the outboard deck sheer line.
 

Completed deck skeleton.
 
As in the previous example in Post #32 of this topic, I "connected the dots" to create the faces forming the cambered surface. (I deleted the curves on the far side of the plane so I didn't have to create 2 million facets, only 1 million...)

Cambered surface created from the camber templates.
 
 
 
You may see where this is leading. Again, to create the deck surface as confined by the outboard sheer line, I created a "cookie cutter" from the outboard sheer line to intersect with the cambered surface. Sketchup allows you to create cutouts of 3D objects using other objects that intersect the one of interest. The cookie cutter's surface is parallel to the z-or vertical-axis of the model.

Outboard sheer line turned into a cookie cutter.
 
After creating the intersection with the cambered surface, I deleted everything but the surface of interest.

 
Intersection that represents the outboard sheer line in the cambered surface.
 
Deleting the surface outside the outboard sheer line, duplicating the half-surface, mirroring it, and rejoining the two half-surfaces yields a fair, cambered deck. All cambers are the same.

Completed cambered deck surface.
 
Finally, taking a look at the orthogonal profile view of the deck, we can see that, while the centerline sheer is smooth, there is a distinct flattening there in the middle, which probably would not be considered "fair" overall. The longitudinal lines in the deck that could represent deck plank edges are no longer parallel to the centerline sheer. This doesn't indicate a problem in form or function, however.

Profile view of a constant-camber deck created by referencing the outboard deck sheer line.
 
So, while this method of constructing a deck might introduce some unfairness in a deck, it doesn't seem to be a significant problem. Recall that the camber round up was exaggerated in this example. With a camber of only 6 or 8 inches, viewing the flattening evident in the above diagram over a length of several hundred feet would be indiscernible, I think.
 
Snide comments about resorting to digital programs to support one's point aside, I don't see any other way to easily and economically illustrate the concepts we are discussing without otherwise resorting to actual plans of actual ships that were built in a particular way. Then what does that prove, except that it worked in that instance?
 
I can't speak about cambers in the forward areas of a ship departing from a fair sheer because I haven't researched those. If anything, those exceptions probably prove the rule. If someone could present an example of such a case, I would appreciate it so I can visualize that situation. I can't conceive of shipwrights having to create numerous deck beams, all with different cambers in order to provide a fair deck in "ye olde days," but perhaps that was the case. It certainly doesn't make geometrical sense to me.
 
Terry
 
 

"Once again into the breach" (Henry V-Shakespeare)
 
Because of the persistent view that a constant-camber deck couldn't produce a fair deck, but one with unfair areas in its surface, and because my last attempt to demonstrate that this was not the case was apparently derived from a non-standard approach to ship design and construction, I decided to experiment and see what the outboard-sheer-line-in approach would produce. I had no preconceived notions on this approach, but it seemed that if the outboard sheer line was fair, then it makes geometrical sense that using constant cambers in attached deck beams would also be fair, since corresponding points on the adjacent beams would fall into a curve parallel to the outboard sheer.
 
Many mentions have been made how constant-cambered decks weren't the case in 16th, 17th, and early-to-mid 18th century ships, and I can understand how that is likely due to the relatively low length-to-beam ratios and quite pronounced sheer lines in those eras. But ships became stretched out in the latter 1700s and through the 19th century, so there was less imperative to hand-tool the deck camber, I would think.
 
So, here goes. Using Sketchup again, I created a generic, non-circular curve in three-space and attached it to a vertical plane that corresponds to the centerline of a fictitious hull. The curve represents the outboard deck sheer of the vessel.

Outboard sheer line in perspective.
 

Plan view of the outboard sheer line.
 

Profile view of the outboard sheer line with the centerline plane behind (looking to port).
 
As before, I created a deck camber edge from a segment of a large circle, then placed its center point on the centerline plane. I also added horizontal and vertical guidelines to ensure each camber template was correctly placed longitudinally and on center. These identify deck beam "stations."

Cambered deck beam template and positioning guides.
 
Next, I dragged the camber template down until its edge intersected the outboard deck edge. This was repeated using duplicate copies of camber templates at each beam station line.

Duplicating camber templates and positioning them at the outboard deck sheer line.
 

Completed deck skeleton.
 
As in the previous example in Post #32 of this topic, I "connected the dots" to create the faces forming the cambered surface. (I deleted the curves on the far side of the plane so I didn't have to create 2 million facets, only 1 million...)

Cambered surface created from the camber templates.
 
 
 
You may see where this is leading. Again, to create the deck surface as confined by the outboard sheer line, I created a "cookie cutter" from the outboard sheer line to intersect with the cambered surface. Sketchup allows you to create cutouts of 3D objects using other objects that intersect the one of interest. The cookie cutter's surface is parallel to the z-or vertical-axis of the model.

Outboard sheer line turned into a cookie cutter.
 
After creating the intersection with the cambered surface, I deleted everything but the surface of interest.

 
Intersection that represents the outboard sheer line in the cambered surface.
 
Deleting the surface outside the outboard sheer line, duplicating the half-surface, mirroring it, and rejoining the two half-surfaces yields a fair, cambered deck. All cambers are the same.

Completed cambered deck surface.
 
Finally, taking a look at the orthogonal profile view of the deck, we can see that, while the centerline sheer is smooth, there is a distinct flattening there in the middle, which probably would not be considered "fair" overall. The longitudinal lines in the deck that could represent deck plank edges are no longer parallel to the centerline sheer. This doesn't indicate a problem in form or function, however.

Profile view of a constant-camber deck created by referencing the outboard deck sheer line.
 
So, while this method of constructing a deck might introduce some unfairness in a deck, it doesn't seem to be a significant problem. Recall that the camber round up was exaggerated in this example. With a camber of only 6 or 8 inches, viewing the flattening evident in the above diagram over a length of several hundred feet would be indiscernible, I think.
 
Snide comments about resorting to digital programs to support one's point aside, I don't see any other way to easily and economically illustrate the concepts we are discussing without otherwise resorting to actual plans of actual ships that were built in a particular way. Then what does that prove, except that it worked in that instance?
 
I can't speak about cambers in the forward areas of a ship departing from a fair sheer because I haven't researched those. If anything, those exceptions probably prove the rule. If someone could present an example of such a case, I would appreciate it so I can visualize that situation. I can't conceive of shipwrights having to create numerous deck beams, all with different cambers in order to provide a fair deck in "ye olde days," but perhaps that was the case. It certainly doesn't make geometrical sense to me.
 
Terry
 
 

Charles,
 
My reference to a "cookie cutter" is literally what I meant. Think of a quasi-cylindrical tube with a cross-section in the shape of the plan view of a hull, which is the white, boat shape in the image. The cutter intersected the camber surface along the z- or vertical-axis, so the result is a true, three-dimensional shape in all dimensions.
 
Crothers claimed that mid-1800s ship decks were constant camber. My post was intended to simply refute the claim that a constant cambered surface could not produce a fair deck surface.
 
As with many areas of creative human endeavor, making absolute claims about how something can be done simply doesn't hold true because someone always comes up with an effective alternative.
 
Terry
 
 

Charles,
 
My reference to a "cookie cutter" is literally what I meant. Think of a quasi-cylindrical tube with a cross-section in the shape of the plan view of a hull, which is the white, boat shape in the image. The cutter intersected the camber surface along the z- or vertical-axis, so the result is a true, three-dimensional shape in all dimensions.
 
Crothers claimed that mid-1800s ship decks were constant camber. My post was intended to simply refute the claim that a constant cambered surface could not produce a fair deck surface.
 
As with many areas of creative human endeavor, making absolute claims about how something can be done simply doesn't hold true because someone always comes up with an effective alternative.
 
Terry
 
 

I had another thought on this subject. The variable camber design was not limited to ancient vessels. The (relatively) modern barrelback runabouts of the early 1900s were designed with a drastically different camber from bow to stern.

Not to beat a dead horse, I thought it would help to illustrate Phil's explanation to show that constant-camber deck construction actually works.
 
Crothers et al claim that an upper edge of a cambered deck beam is a segment of a huge circle—too large to lay out on a lofting floor. So that is why the graphical approximations for a circle segment shown in earlier posts were developed. The following image shows a line of circles of equal diameter arranged along a vertical, rectangular plane. The edges of the circles adjacent to the rectangle represent the edge cambers of a series of deck beams arranged along a straight sheer centerline. This will be the basis for "constant camber." Now, please bear with me. All the following images were derived from a Sketchup model.

 
If you connect the edges of the circles in such a way to create a surface on both sides of the reference centerline rectangle, this represents a cambered surface with no sheer. In Sketchup, you have to create a bunch of small rectangular faces to produce the surface, which I didn't illustrate at this point. However, taking a side view of the constructed cambered surface, it would look like this:

 
The vertical edges within the surface are the included edges of the circles, or camber curves. The horizontal edges form the faces of the cambered surface. Note that these latter edges are all parallel with the straight centerline sheer—a geometrical certainty in a cylindrical surface.
 
Let's remove the portions of the circles not included in the cambered surface to reduce clutter.
 
This is a plan view showing the surface. (The deck/hull centerline is left-to-right in this view.)

 
Again, the longitudinal lines that connect the individual deck beams (the horizontal lines) are parallel to the centerline of the vessel.
 
Here is a perspective of the cylindrical cambered surface looking aft along the centerline. Obviously, the curvature of the camber is exaggerated for this discussion:

 
Now, getting to an actual vessel deck, lets assume the centerline in the profile view is a generic curved sheer line. Then we reconstruct the same surface from that starting point. Again, the vertical rectangle with the curved edge represents the profile view of the centerline plane of the hull deck.

Here, the cambered beam edges are arranged along the centerline sheer. Now, we create the cambered surface by connecting the nodes visible in the image with line segments (this is a process in Sketchup).
 
This results in the "saddle" shape that Phil mentioned in his post.

 
If we look at the profile view of this surface, we see that the longitudinal lines in the surface are all parallel to the centerline (sheer) curve. These lines could represent deck plank edges. They neither converge or diverge from the sheer profile in a constant-camber situation.

 
So, how does this look in a real-world application where the deck beams are constrained by a hull? Let's take a hull-shaped "cookie cutter" and create a deck from this saddle shape that fits into a hull. I stretched out the cambered surface in the longitudinal direction to provide a more realistic proportion of length-to-beam.

 
After cutting out the hull shape on one side, eliminating the parts of the surface outside the cookie cutter, and duplicating, reflecting and joining the two halves of the surface, this is what we have in perspective:

 
Ignoring the facets, which are artifacts of the digital program, this surface represents a sweet and fair moulded deck. All deck beams have the same camber.
 
Again, a profile view of this surface shows that all longitudinal lines on the surface are parallel to the centerline sheer.

 
Note that the lower edge in this image is the outboard deck sheer line from which the rail line can be projected. However, to be perfectly honest, David (Druxey) reminded me that ship designers started with a sweet and fair rail sheer line, then established the positions of the outboard ends of the deck beams below that, and then from this  information, developed the centerline sheer line as dictated by the widths of the deck beams and their camber. This is correct, but working the process in reverse of what was presented here still yields a fair curve without having to create separate cambers for each beam.
 
I hope this illustrated explanation will help visualize what several of the contributors to this topic have been saying. Constant-camber geometry likely applied to vessels at least from the mid-1800s on, if not earlier, so modelers experienced with earlier vessels may be justified in having a different view of this issue.
 
Cheers,
Terry
 
 
 
 
 

One thing you could do is to enter all information you have in Delftship and then shape the hull respecting the given data (you can lock data points). Once done, you can create frames at every location and I would imagine it is sufficiently accurate for a model. I found Delftship quite intuitive and worth the effort to get to know how to use it (I used a ship contract to determine the hull shape only with no requirement for fancy looking ship in 3D software). The free version is sufficient to do this.
Piet