The German specifications follow with but few exceptions the pattern of U.S. Naval specifications, and include general specifications for hull, machinery and electrical components, detail hull specifications, special machinery specifications and special electrical specifications.  In addition, separate specifications are provided for plans, for instruction manuals, for materials, for methods, and for individual components.  Related to these, and considered as specifications by the Germans, are standard plans for other individual components, for example, valves and hull fittings.  
          Much greater use is made of the standards set up by the German counterparts of the several American engineering societies and standards organizations than that made by the U.S. Navy.  
          The general specifications are shorter then the American counterparts, and do not include as much detailed information.  
          The detail and special specifications closely parallel, in content and arrangement, the corresponding USN specifications.  
          Specifications for plans and for instruction manuals are very detailed, and list large numbers of items which must be shown or discussed.  Methods specifications, for example, painting specifications, are also very detailed.  
          Materials specifications and standard plans aim at conciseness, and provide a large amount of information in tabular form with a minimum of explanatory text.  
          Specifications and plans are cross-identified to about the same degree as in U.S. naval practice, in which "S" group sections in specifications and plan numbers are the same.  Also as in U.S. naval practice, the group numbering carries through to include allowance lists.  
  Comment:  When reading the specifications, one is immediately aware of a high degree of pigeon-holing.  Everything has  
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  its own place, and is to be found in that place.  Unfortunately, not all elements of a specification are so easily classifiable, and the result is that there is a lack of tie-in between the different sections.  There will be a section on the hydraulic system, for example, and another on the items operated on the hydraulic system, but there is no reference made to how these components are related.  Reference to three or more publications may become necessary before an exact relationship can be established between an operating unit and an operated unit both of which may be on the same bedplate in the ship.  
          Specifications for methods, such as the painting specifications, carry about the same amount of detailed information as the corresponding USN specifications, but the normal tendency of separate specifications for parts of the job is to require an excessive amount of detailed compliance.  This is particularly true of the specifications for plans and for instruction books.  
          The German instruction books were complete and detailed, and were intended to provide a complete description of all parts of the vessel.  A set comprised the following separate publications:  
          a)  A general hull information book  
          b)  A general machinery and electrical information book  
          c)  A pictured list of all hull valves and other hull fittings  
          d)  A list of all points to be lubricated  
          e)  A separate instruction book on each of the following:  main engines;  circulating water system;  lub oil system;  fuel oil system;  diesel air and exhaust system;  shafting;  shaft clutches, gearing and propellers;  main motors and generators; main switchboard, main power wiring, main blowers and air conditioning;  battery system and battery ventilation;  auxiliary switchboards, auxiliary power, wiring and lighting circuits, motors and equipment; cooking and refrigerating; command, announcing and indicator systems;  gyro compass;  magnetic compass;  ballast tank blow, venting and pumping, and WRT system;  compressed air system;  trim and drain system;  hydraulic system;  periscope drive (mechanical part);  each type of periscope; drying gear;  rudder and system (mechanical portion); rudder and plane system (electrical portion - where provided);  safety arrangements;  periscope depth and extension gauge;  fire main;  drinking and wash water system;  fresh  
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  water stills;  ventilating, air refrigerating and oxygen system;  ship's heating;  WC arrangements;  anchor and windlass;  workshop equipment;  out-board motor;  torpedo handling arrangements.  
          Additional separate books are believed to have been provided for the electronic equipment and ordnance arrangements, but with the exception of a few scattered plans and technical books in non-standard format, no such instruction material has been encountered locally.  
          One copy of each book was directed to be provided on board, although sets were incomplete on vessels surrendered at Portsmouth.  
          Each book followed a standard form, which consisted of:  
          a)  constructional data, dimensions, materials, ratings, test conditions and list of suppliers  
          b)  a description of each part of the system  
          c)  a set of operating instructions for the entire system, with related precautionary notes  
          d)  instructions for maintenance, including what to do for laying up  
          e)  instructions for disassembly and reassembly  
          f)  a description of operating difficulties, usually with a table of symptoms and how to correct them  
          g)  a statement of possible substitutions on case of a system breakdown, or casualty to any part  
          h)  a list of on-board spares  
          i)  a list of reference plans  
          j)  a group of plates consisting of photographs, diagrams, tables, curves and other material necessary to illustrate the text.  
          Although certain of the reference plans were to have been carried on board, no such plans were found on any vessel surrendered at Portsmouth.  Further, not all vessels had complete sets of instruction books.  
          The amount of information contained varies quite widely from book to book, and from vessel to vessel type.  The quality of the information also varies, as some authors seem to have been more concerned with style than with telling a story simply, and others apparently have not all the facts.  Further, while the books are bound in such a way as to permit easy substitution of corrected pages, they are in fact a static collection of information, and only rarely have been found to cover all  
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  system changes.  
          The worst set is the one on the type XXI vessels.  In an effort to provide as much information as possible certain publications have been released which fail in major particulars to represent the vessels as actually completed.  They disagree among themselves on related data, and must be used with discretion.  The printed general information book is dated July 1944, but certain systems instruction books were still in draft form in May of 1945.  
          Related to the instruction manuals, and used for ready reference in lieu of reduced sized plans, are the sketch books.  These are of two types, one of which consists of schematic diagrams of piping systems, including ventilation, and the other of which consists of diagrams showing electric leads, and schematic layouts for the main and auxiliary switchboards.  Four copies of each are supposed to be on board each vessel, although this number of copies was rarely found.  
          The sketch books provide much ready information.  They are of a handier size than the reduced size plans which are the nearest USN equivalent, and provide about the same amount of information as the system diagrams which form a part of the USN plan books.  The fact that they can be carried about in a hip pocket greatly increases their value for ready reference.  
          Also related to the instruction books are the schematic piping diagrams found at the different system manifolds.  These are identical with the diagrams in the instruction books and the sketchbooks, but of larger size.  
          Naval Technical Mission in Europe report 304-45 on Training Aids describes the situation leading up to the preparation of the instruction books, and the general method followed in preparing them.  Use at Portsmouth confirms their value.  
          It must be added, however, that practice departed from principle, and that while the books provide much valuable information, the corrections for the purpose of bringing books up-to-date are all entered in long hand.  The only exception to this is in the case of the type X-B machinery sketch book, which has been generally corrected by inserting new pages to bring it up-to-date as of  
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  the end of 1944.  The condition persisted in spite of directives requiring for, correction purposes, reports of changes made and differences encountered.  
          The inaccuracies found in the books, as distinguished from the failure to show alterations, are caused by the fact that some books were printed in advance of construction, and could not reflect design changes made after publication date, and by the fact that the war conditions made necessary substitution of other items and other materials for those originally specified.  
          The volume of detailed information carried on board is probably less than that carried by USN vessels.  The information is, however, in a more accessible form, and (with few exceptions) more portable.  The pocket sketch books are notable examples.  
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