The Station Section Method
First I will describe concept behind this POF method and its advantages.
My first scratch build was Kate Cory, plans by Eric A.R.Ronnberg Jr.., 1/4":1'.
I used the Hahn method. It is an excellent first scratch POF method to learn from. Hahn was building at 1/8":1' scale in his presentation. At this scale the waste of framing stock is insignificant. At 1/4" scale the wood is eight times the volume and the loss to waste is noticeable. For a skills development project the loss is acceptable if domestic species of wood is used. I lofted each frame by hand on vellum. The process was very time consuming, tedious, and frustrating. I found that I cannot plot acceptable curves. An easier lofting method became a priority.
Doing the frames as scale appropriate individual timbers was also a priority. Drawing and building each bend as an isolate unit became something to avoid. On a large ship, this can involve drawing up to 200 or more individual frame shapes.
After many starts and stops I have developed a method that works for me. I have tried different names - station sandwich method is one - but right now Station Section Method is my choice.
On lines plans of a ship, the shape for each station is already on the plan. There are usually between 20 and 30 individual shapes. No plotting is necessary.
This means that all of the frames between two stations must be built as a stack, as a unit, as a section. That is: if having to plot points and draw 200 to 300 new curves is to be avoided, the station shapes have to stand for their associated frames. The actual shape of most of the frames is determined by how the wood itself is shaped.
My reading indicates that the 1670's era Navy Board framing was done as sections. Even more significant is the probability that the mold loft only chalked the frame shape at each station on the floor and only made patterns for the timbers of each station. The patterns had marks - sirmarks - for each of the frames between each station. The shipwrights in the yard did the interpolation.
There needs to be a way to align the frames in each section. The two frames in a bend have very little area inside the frame that allows for a perpendicular line to be inside the two frames for most of the hull. This means that there is zero chance that a whole section of frames can be aligned using the inside bodies. A common alignment that is outside the frames has no limitations. It just means that there is more wood to remove when shaping. By having precise multiple alignment points there is an identical pattern in precise alignment at each end of a stack of frames (station section).
The locator points to mate the common faces for two sequential station sections are easily within the body of the frame. There is a limit on how deep a hole can be drilled without exiting the frame and marring the outside or inside face,
I also include temporary filling timbers in the spaces. I use construction Pine for this. It is low cost and easy to work. The frames in each section are more stable and shaping is much easier. The hull is a solid surface for shaping, faring, and sanding. It is not like trying to smooth a picket fence or bumping along rail road track ties. The frames cannot move while being abused.
The framing style is not limited -- or constrained by this method.
Some of the possibilities to be shown on Monday.
