CACrown ArchivesThe cinema collection
Menu
Research dossier · General Reference

SM U-40 (Germany)

1914 Type U 31 submarine

Cross-disciplinary reference desk with index cards, atlas, dictionary and catalogue
General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionMay 11, 2026
Entity authorityQ835050 ↗
Source-derived summary

SM U-40 was a German Type U 31 U-boat of the German Imperial Navy (German: Kaiserliche Marine) during World War I.

Her construction was ordered on 12 June 1912 and her keel was laid down on 3 April 1913 by Germaniawerft of Kiel. She was launched on 22 October 1914 and commissioned on 14 February 1915 under the command of Gerhardt Fürbringer. Second officer was lieutenant Rudolf Jauch (of the Jauch family).

U-40 conducted one patrol, without sinking a ship.

Design

Type U 31 submarines were double-hulled ocean-going submarines similar to Type 23 and Type 27 subs in dimensions and differed only slightly in propulsion and speed. They were considered very good high sea boats with average manoeuvrability and good surface steering.

U-40 had an overall length of 64.70 m (212 ft 3 in), her pressure hull was 52.36 m (171 ft 9 in) long. The boat's beam was 6.32 m (20 ft 9 in) (o/a), while the pressure hull measured 4.05 m (13 ft 3 in). Type 31s had a draught of 3.56 m (11 ft 8 in) with a total height of 7.68–8.04 m (25 ft 2 in – 26 ft 5 in). The boats displaced a total of 971 tonnes (956 long tons); 685 t (674 long tons) when surfaced and 878 t (864 long tons) when submerged.

Editorial summary

“SM U-40 (Germany)” enters the record as 1914 Type U 31 submarine. Crown Archives preserves that source wording while asking what U-40, Germany and Type can confirm, complicate or overturn.

Editorial reviewA concise reference frame for defining the subject, testing terminology and identifying the institution closest to the evidence. The current lead gives the account dated anchors—1912, 1913, 1914, 1915—that can be checked directly. The selected authority fields contribute no independent date. Its strongest next move is a source search built around U-40, Germany and Type.
Editorial analysis

Why this record matters

“SM U-40 (Germany)” is worth following because a concise public description often conceals a longer documentary argument. Here, U-40, Germany and Type provides the most credible route into that argument.

Evidence profile

Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated May 11, 2026. The linked authority identifier is Q835050. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1912, 1913, 1914 and 1915.

Critical limits

The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.

How to read it

Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.

Best used for
  • Subject orientation
  • Search vocabulary
  • Locating named sources
Verify next

The closest primary source, responsible institution and strongest cited specialist reference.

Three-step research path

  1. Establish the record: confirm the title “SM U-40 (Germany)”, its source revision and the description used here.
  2. Expand the search: follow SM U-40 (Germany) primary sources, SM U-40 (Germany) archive and U-40 research across catalogues and specialist indexes.
  3. Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.

Questions for further research

  1. Which source most directly establishes the central claim about “SM U-40 (Germany)”?
  2. Which cited source is closest to the event, object or claim?
  3. Which institution is responsible for the underlying evidence?
Subject index

Search terms from this dossier

Source & attribution

This entry incorporates text from “SM U-40 (Germany)” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.