Unknown Titanic plans? Requesting help identifying


A. Gabriel

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I made mention of this a week or so previously, in a different thread. The National Geographic docu-series Rebuilding Titanic has, in its first episode, what appear to be hitherto unknown plans of Titanic, shown here from 4:50 to 5:00. The shell plating plan was previously seen on-camera at around the 4:13, but the plans shown in the link above appear to be for the hull (including details of the frames and the stem) -- the only trouble is I have no idea exactly which plans they are, none of the previews I could find of Titanic plans online match up.

Any help identifying said plans would be very welcomed thanks. Are they part of the lines plan? The framing plan? I'm stumped, honestly.
 

Harland Duzen

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It would appear the plans show the shape of the Titanic's stem and the position of frames / overhead girders in the bow.

Similar diagrams (that look a lot different than the documentaries one's) of the Bow's stem can be found on Page 90 and the shape and shell plating arrangement can be found on Page 148 in "Titanic: The Ship Magnificent Part 1"

I hope this helps.
 

B-rad

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The plans Harland speaks of is drawings based off the plating plans. The video pictures may just be an extension of these plans. A good thought may be trying to reach out to someone in the video (or the producer/s), emailing them and asking what plans they specifically used, I find that most people, when reaching out, are quite helpful when it comes to 'Titanic' related topics. That is unless someone answers here first, but even in reaching out maybe they have some other knowledge they can share to help with your work.
 
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A. Gabriel

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Many thanks, again. Will attempt to make contact with the folks over yonder at first opportunity.

Also, just as a curiosity, notice that the plans shown in that video have the distances from the keel bottom (for the frames) and the distances from the fwd. perpendicular (for the stem at the given waterline marks) in what appears to be millimeters*. Since when was the metric system involved in the plans and building of a British-owned ship?

* I plotted the visible distances on GeoGebra, assuming the dimensions shown are in mm, and managed to recreate the shape of that section of stem perfectly -- though as it turns out to get the curve right, frame 155 has to be 3'6" from fwd. ppd., not 3'8" like I'd earlier calculated from builder's LBP.
 
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B-rad

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It does use millimeters (24in = 609.6mm)… I'm wondering (also based on this along with the clarity & boldness of the drawings) if this isn't something that they drew up themselves for the show based on original plans?

They have a facebook page, found here Titanic: the Mission so maybe you can get ahold of someone via it. I don't think anyone's posted on there for a while, but worth a shot.
 

A. Gabriel

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The fact that some of the distances given have two decimal places is also suspect. I doubt Thomas Andrews or any of the designers were scrupulous enough to measure distances to the 0.01 mm level, availability of micrometer calipers aside.
 
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In Titanic's day blueprints were not used to construct ships or even boats. The reason is quite simple. A ship must be drawn in three dimensions. Any given point must line up with that same location on the plan, the elevation and the transverse views. Pencil lines are simply too "fat" to be accuate, so the process of "lofting" was developed. A loftsman would take the drawings and enlarge them to full size. This was normally done on a smooth, white floor installed over the building shop -- hence the term "lofting" since it was done in the loft. In the process lines would be "ooched" one way or another in order to achieve the 3-dimensional meetings described above. If the ship was a one-off, that was it. However, if the vessel being lofted was first of a series, the loftsmen would create a "table of offsets" giving the three critical measurements taken from the full size views on the loft floor.

Something else, even parchment or vellum used in conventional drafting changes size with humidity.. This means that it is impossible to take accurate measurements off a scale drawing. This is one more reason you never...repeat, never...take exact measurements off a reduced scale drawing.

As anyone who has done a lick of carpentry knows, "12" is the magic number. It can be divided in half as well as iinto thirds and quarters with simple in-the-head mathematics. Best, there are no pesky fractions or decimals to deal with in these divisions. Until the irrational metric system began to dominate, every bloke in the shop knew the unique math around the number 12. Alas, those were the days! Actually, those are still the days in shops around the world. The number 12 still dominates. (Example: The standard size of plywood is still based around the globe on 4 feet of width and 8 feet of length.)

But, I digress. A table of offsets lists dimensions in feet and inches as well a eighth inches. Plus there are "ticks." A number on the table might read 10-2-2, which would mean "10 feet, 2 inches, and a two eighths." If the same number were written 10-2-2+ it would mean "ten feet, 2 inches, two eighths plus a 'tick' which is 1/16th of an inch. A minus sign at the end would make it "minus 1/16th of an inch.

The reason for "ticks" is human memory. Its easy enough to learn feet and inches. Keeping all fractions in 1/8th inch simplifies that part of what you have to keep in your head. And, you don't memorize anything for a "tick" which is just half an eighth. Believe me, when you have to climb down six feet off a building platform to consult the plans, and then climb back up you want to use a system that makes carrying measurements in your noggin as easy as possible.

While the system sounds crude, it is really quite workable. Wood swells across the grain so planks gain or lose in width sometimes during the working day. Steel gets longer or shorter as it heats and cools. In either case, the measurements made in the morning would not necessarily match precisely those taken at 2:00 p.m. So, there must be a bit of a "fudge factor" in all of this.

-- David G. Brown
 
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A. Gabriel

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In Titanic's day blueprints were not used to construct ships or even boats. The reason is quite simple. A ship must be drawn in three dimensions. Any given point must line up with that same location on the plan, the elevation and the transverse views. Pencil lines are simply too "fat" to be accuate, so the process of "lofting" was developed. A loftsman would take the drawings and enlarge them to full size. This was normally done on a smooth, white floor installed over the building shop -- hence the term "lofting" since it was done in the loft. In the process lines would be "ooched" one way or another in order to achieve the 3-dimensional meetings described above. If the ship was a one-off, that was it. However, if the vessel being lofted was first of a series, the loftsmen would create a "table of offsets" giving the three critical measurements taken from the full size views on the loft floor.

(...)

But, I digress. A table of offsets lists dimensions in feet and inches as well a eighth inches. Plus there are "ticks." A number on the table might read 10-2-2, which would mean "10 feet, 2 inches, and a two eighths." If the same number were written 10-2-2+ it would mean "ten feet, 2 inches, two eighths plus a 'tick' which is 1/16th of an inch. A minus sign at the end would make it "minus 1/16th of an inch.

(...)

-- David G. Brown
Speaking as a chemist-in-training who makes use of the metric system on a massively regular basis I will admit, while it is pretty nifty for handling very large or very small quantities (thank you, powers of ten), it is a right pain in the redacted when it comes to more human-sized measurements. That said, I'm now curious as to the existence of a table of offsets for the Olympic class, whether one exists and if it can be found. This forum has been around for nearly two decades, and if nobody has found it in that time, the offsets table probably has been lost to history.
 

A. Gabriel

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upload_2018-7-5_12-24-42.png


Here's the plot of the measurements taken from the unknown plans. The y-axis serves as forward perpendicular, points A-K mark the position of the stem at frames 155 to 145, points L-S mark the position of the stem at the baseline of various draft marks at 3 foot intervals (12, 15, 18, etc) to the 33-foot mark. Point T marks the position of frame 126, where the stem begins to rise from the ground/keel bottom according to the Beveridge profile plan. The frame points were positioned assuming the distance of frame 155 from forward perpendicular to be 3'6", which gives the best fit for melding the two disparate sets of curves into a single smooth one shown here.

Edit: The horizontal lines notated (only one of which is shown in the graph) mark out the major vertical dimensions of the ship's hull: draft fore (34'6"), and depth (64'6").

It looks like some of these measurements were taken from an as-yet undiscovered offset table? Point I (stem at frame 147) is exactly 10'6" from the ground/bottom of keel, point P (stem at 24' mark) is 3' 6-1/2" from forward perpendicular (3-6-4), and the heights for frames 145 to 151 are given exactly to tenths of an inch when converted out of metric. Does anyone know of the existence of a table of offsets for the Olympic class?
 

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