Aufmaßbuch der "Bismarck"

[Ulrich Rudofsky]

Has anyone ever seen an “Aufmaßbuch” or “Schnürboden-Aufmaße” booklet for the BISMARCK? I would translate it as “lofting or loft lines book”. It contains “Aufmaßtafeln”, tables of offsets (?) for each new ship construction. I wonder if this material still exists for the BISMARCK.
Example: https://www.weitze.net/detail/04/U_Boot ... 97904.html

[Olaf]

Learn a new word every day, quite a slogan for a translator, HA!

I didn't even know what a "Schnürboden" is - today it is also known as "Reißboden" (a hall or other large room for drawing "Linien- und Spantenrisse" at scale 1/1 directly on the floor) - and I'm not quite sure if this kind of technique was still in use for ships of battleship size.
It would be nice to know what is really meant with the 'offsets' - maybe derivations from the original plans, such as "last changes in the field"?

As your example is for the type XVIII submarines, which MAY have been produced in subsections by various manufacturers, I can only assume that an offset table simply sets the tolerances or limits in which the parts produced can be accepted for further use. I've read that not few of the subsestions for the type XXI boats could not be properly alligned/assembled due to differences in their overall measurments coming from various workshops, e. g. the overall diameter in cross-section from supplier A was an inch or two greater than the adjacent diameter of subsection from supplier B.

And no, I never heard anything like this related to Bismarck. A booklet like this would be quite a find!

Happy searching ~ Olaf!

[Ulrich Rudofsky]

Some wooden boat building schools still use the old-fashioned lofting procedures as far as I know. The Maine Maritime Museum has a building where you can see how this was done. Now it is all done by CAD.

“Offset” in naval architecture: Any of the coordinates by which any point on a hull being planned is located. The German word for offset, in this case, makes more sense: “Übertragung” i.e. transfer. (Another word for offset is"Absatz",but it does not apply here.)

The frame drawings were tranferred and enlarged to full scale on plywood (?) and sent to the foundry or metal shop. The method employed before that, as I understand it, was to take the lines off from large half-hull models.

Leibiger&Leibiger German-English and English German Dictionary for Scientists. 1950, J.W. Edwards, Ann Arbor, Michgan.

http://www.ds-t.com/software-cd/softwar ... ipcam.html

[Ulrich Rudofsky]

addedum to the above: Detailed descriptions of the “Schnürboden” method are in Kriegsschiffbau, H.Evers, 2nd ed., 1943 (rev. from 1934), part 7, pp. 354-355. It also explains the old word: “aufschnüren” means “aufzeichnen” (to draw); however, “aufschnüren” now means to untie.

[Bill Jurens]

Although the details varied somewhat from country to country, and often from shipyard to shipyard, the overall method of shipbuilding -- and the use of the table of offsets -- remained more or less the same.

During the design process, a set of hull lines was defined by the naval architects. These were to relatively small scale -- about 1:100 for a large ship --- and were used to make half-block models to assist in planning the plating arrangments, and to make models for the towing tank. Usually, some refinements were made to the original design after the towing tank results are in, and a second set of faired lines was prepared, again at about scale 1:100. These faired lines were then translated into a full-size body plan at the shipyard where small errors in the 1:100 plan are smoothed out, often using a waterline and sheer plan as well, often drawn to 'contracted' scale, i.e. full size transversely and perhaps 1/4 full size longitudinally. The full size body plan was typically used to make up the various templates used to construct the ship itself. If the ship were quite small, and a large number of ships were to be made, the templates might be stored somewhere to be used again. With big ships this was impractical, so precise measurements of the full size body plan (and often the other views as well) were made before the original lines were erased from the mold-loft floor. These measurements, rounded to a precision of 2-3 mm or so, were placed in a large book called a table of offsets. This was very useful if the ship needed repairs, etc., insofar as the offset book allowed any portion of the original full-size mould loft body plan, etc. to be reconstructed again so that new plates, etc. could be made to the correct size. Usually, at that point yet another set of 1:100 lines was prepared, often with the notation "taken from mould loft offsets". This would typically vary slightly from previous versions, and -- in conjunction with the tables of offsets book -- was considered definitive.

While a table of mould (or mold, spelling varies...) loft offsets would be of historical interest, it would be of little practical value today unless one wanted to build a full-size ship again. For model-building purposes, etc., the regular 1:100 lines plan would give you all the information you needed. The only exception might be in areas where the lines on the lines plan overlap one another to the degree where they are difficult to separate from one another. In those cases, the table of offsets usually makes the actual contours easy to sort out. But usually, particularly if one has experience, they can be sorted out on the lines plan as well. The table of offsets booklet is also useful if one is having more than one shipyard do the construction of various ships in a class. The "lead yard" lays out the master lines plan on their mould loft floor, and sends a copy of the offset book to the other shipyards in the group (This is a lot easier than shipping templates...). The other shipyards in the team use the offset book to lay off their body plans, etc, which -- at least in theory -- should match very closely.

Bill Jurens

[Olaf]

Thanks to both of you for your comprehensive explanations. They probably have used something like this to rebuild PG's (Prinz Eugen) and LW's (Lützow) sterns - although I can't recall right now if in both cases the 'lead yard' was involved...

Happy modelling ~ Olaf!