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[gof]

Just asking if I'm on the right track with checking the accuracy of the frames on the body plan and on how to add new frames to the plan.

 1. Enlarge body plan to the inside of the hull for the scale that you want.

2. Draw a base line to the full size of the length of the model.

3. Measure accururately where each frame is on the plan then mark them on the base line that you have drawn and always measure in the same direction  ie: from bow to stern or stern to bow

4. Draw a line perpendicular to where each frame has been marked on the base line say in a black pen for frames that are shown on the plan.

5. Next draw a diagonal line on the enlarged plan then measure the distance from the center line to where the line intercepts the frame (say frame 15)

6. Then go to  frame 15 on the base line. Then measure along its perpendicular line and place a mark on that line the distance that you measured on the diagonal line.

7.Once all the frames have been measured and marked for that diagonal line, Draw a line that connects all the dots, as long as this line looks ok (no dots causing the line to jut out from where it should be)

8. Once you are sure that all the frames in the plan are accurate. Decide on where you want to place the new frames taking into account the room that you will need to place all the gear that you will need to run the boat. say draw the lines in a red pen.

9 Measure the distance from the base line to where the new frame line (marked in red) intercepts  line that you have drawn in step 7.

10 Then on your enlarged plans measure along the diagonal line the distance where the new frame intercepts the line that you have drawn in step 7 and mark the new frame on the diagonal

11 Repeat the steps 5 - 10  till you have enough marks to draw in all the new frames are done.


lee

the only stupid question is the question that you dont ask

[dreadnought72]

I'm not totally sure where your diagonal line (5) is going from.

Here's what I did with the Dreadnought. (WARNING! Excessive scribbling on The Book follows. Viewers of a nervous disposition, and those who foolishly believe in my sanity ought go to another thread now.)

Below is part of the page covering the waterlines. Top is an elevation, middle is a plan (both in a useless-to-me 1/384th scale) and bottom are cross sections (1/192nd scale). The waterlines are parallel to the keel, and lettered A, B, C, etc. M is main deck, U is upper deck, and Fl is foredeck. These are not parallel to the keel.



How far apart are the waterlines? With careful measurement, the best fit of the distance from G to A in Imperial Units (what the ship was built in) makes each waterline four feet apart. The lowest waterline (G) starts 2'6" above the keel. On a BIG sheet of paper I drew the elevation view first - a line for the keel, and parallel waterlines above it. G, at 2'6" is 5/12" at 1/72nd scale. Four feet apart is 2/3rds of an inch. Once done, I plotted the section positions on the elevation (they're 24'6" apart for some reason) marked these (they're lines perpendicular to the keel) and measured the deck-edge heights and marked these on the big elevation. These non-parallel points were joined with smooth curved lines.

On to the big plan view: above the elevation's highest point I left a gap and drew another keel line, parallel to the waterlines and the keel line of the elevation. I marked out the section positions on this and drew these lines (once again perpendicular to the keel).

Now to the maths:



The handy scale below this elevation shows station positions. WTB stands for watertight bulkhead. The forward perpendicular (FP) is the bow at the normal waterline. The aft perpendicular (AP) is the axis of the rudders. I know Dreadnought was 490' between these perpendiculars (PP), and 526' length overall (LOA).

Now, the station positions change in length along the hull. And with a bit of care, you can see that there are 38 & 2/3rds from FP to station 40. There are 160 somewhat longer ones between station 40 and 200 (off the page), and 18 between 200 and the AP. Given the forward and aft stations are 3' apart, and the central ones 2' apart (4' in the drawing, but they're number evenly and there are no "odd" stations used in the plan) you get 490'. 

The book shows good elevations of the bow and stern at a larger scale, with stations and bulkheads in place which enabled me to scale up and draw the bow and stern elevations on the right stations to get the correct LOA. Result!

On to the big plan view. Knowing the beam of the Dreadnought I knew the maximum width that the plan could be. Scaling up the cross-sections I could plot the waterlines onto the plan, making sure the maximum breadth didn't exceed the known beam. These points were faired, and from the big plan I took off this information to make a few trial sections at my desired scale. With a little bit of tweaking of the waterlines on the plan, all became correct enough (within a mm).

Now I could mark out MY positions for frames for building: these are 18' apart (3" at scale) and run from station 4 aft. Following this it was trivial to draw out sections using the big plan's waterlines and deck edges as a guide.

The cross section shown in the first image is the edge of the frames: hull plating adds to this (and during a build, the widths of most battleships "fell open" a few inches or so.) On my plotted sections, I removed 3mm from the outer edge to get a frame which would "return to accurate" once 3mm of hull skin was put on.

And there you go.

I must admit, it was extremely useful to have the big plan and elevation to accurately nail the turret centres, funnel and superstructure positions - these all coincide with stations. "A" turret at "54", for example. And it was very useful to draw onto these images prop shaft centrelines (in plan and elevation) which enabled me to pre-drill holes in my ply frames to locate them during the build.

I don't know if this is how anyone does it, but - for scaling up small scale plans (which are somewhat useless) to recovering their accuracy, works for me.

Andy