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The Encyclopedia of Horology

Wristwatch · Tank wristwatch

1945 Omega Cal. R17.8 Tank Case Wristwatch

Partially verified

This vintage Omega tank-style wristwatch dates from 1945 according to the source dealer. The piece features a rectangular 14K yellow gold-filled case measuring 21 by 32 mm with elongated curved flanks. According to the seller, it is powered by an Omega manual-wind mechanical movement, calibre R17.8, bearing serial number 10356600 and featuring 17 jewels. The dial shows extensive age-related mottling and patina across its surface, fitted with black Arabic numerals, an outer rectangular railroad minute track, gold-toned hands, and a subsidiary seconds register positioned at 6 o'clock. It is presented on a gold-toned Speidel flexible expansion bracelet.

Front view of the 1945 Omega Cal. R17.8 tank case wristwatch on an expansion bracelet
Front view of the 1945 Omega Cal. R17.8 tank case wristwatch on an expansion bracelet — Second Hand Horology. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
secondhandhorology.com
Category
Wristwatch · Tank wristwatch
Maker / attribution
Omega
Reference
Not recorded
Catalogue / lot identifier
WA-4942
Source-reported date
1945
Country
Switzerland
Source-reported serial
10356600

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Case Construction and Exterior Dimensions

The watch features a rectangular tank case reported as 14K yellow-gold-filled. The seller records dimensions of 21 by 32 mm for the case, 23 mm with crown, a lug-to-lug length of 42.8 mm, a case thickness of 8.1 mm, and a lug and band width of 14 mm.

Visual observation shows a rectangular gold-toned tank case with subtly curved flanks and straight hooded-style lug ends. The piece is mounted on an articulated Speidel-style flexible expansion metal bracelet, documented in the listing as a 'Speidel flex bracelet'.

Evidence for this section
  • “Case 21 x 32”
  • “Case w/Crown 23 Case Lug to Lug 42.8 Case Thickness 8.1 Lug Width 14 Band Width 14”
  • “Rectangular gold-toned tank case with subtly curved flanks and straight hooded-style lug ends”
  • “Mounted on an articulated Speidel-style flexible expansion metal bracelet”
  • “Speidel flex bracelet”

Dial Configuration and Observed Condition

The dial displays severe all-over mottling, discoloration, and patina. It features printed black Arabic numerals alongside an outer rectangular black railroad minute track, gold-toned hands, and the Omega name and logo at the top.

Direct observation confirms a subsidiary seconds register positioned above the 6 o'clock marker. The vendor listing description erroneously claims that the 'sub-second hand is at I o'clock position'.

Evidence for this section
  • “Dial exhibits severe all-over mottling, discoloration, and patina”
  • “The original white dial showcases patina and age, black Arabic Numerals with black "railroad" minute track and matching gold hands.”
  • “Sub-seconds register positioned above the 6 o'clock marker”
  • “The sub-second hand is at I o'clock position.”

Movement Specifications and Interior Markings

According to the seller's documentation, the watch houses a manual-wind Omega movement, calibre R17.8, inscribed 'OMEGA Watch Co. Swiss Seventeen 17 Jewels Cal. Omega R17.8 10356600'. The seller claims an operating frequency of 21,600 vibrations per hour and a 45-hour power reserve.

The interior case back is reported by the seller to be marked 'Omega 14K Gold Filled' and 'T363989'. Neither the movement nor the interior case back markings are visible in the provided exterior photograph, and their verification relies solely on the dealer's transcription.

Evidence for this section
  • “OMEGA Watch Co. Swiss Seventeen 17 Jewels Cal. Omega R17.8 10356600”
  • “Omega 14K Gold Filled T363989”
  • “45-hour power reserve, and operates at a frequency of 21,600 vibrations per hour.”

Open research questions

  • Can interior photography or direct examination confirm the movement serial number 10356600 and case back stamp T363989?
  • Does the claimed 21,600 vph beat rate match the technical specifications of vintage Omega calibre R17.8?
  • Does movement serial 10356600 correlate to standard Omega production records for circa 1945?
  • Which casemaker produced the 14K gold-filled case stamped T363989?

Source evidence

Recorded claims and source quotations for 1945 Omega Cal. R17.8 Tank Case Wristwatch
FieldSource-reported valueSource quotation
CalibreOmega R17.8“Cal. Omega R17.8”
Jewel Count17 Jewels“Seventeen 17 Jewels”
Movement Serial10356600“10356600”
Case Back MarkingT363989“T363989”
Case Material14K Gold Filled“14K Gold Filled”
Case Dimensions21 x 32 mm“Case 21 x 32”
BraceletSpeidel flex bracelet“Speidel flex bracelet”
Case Lug to Lug42.8 mm“Case Lug to Lug 42.8”
Case Thickness8.1 mm“Case Thickness 8.1”
Lug Width14 mm“Lug Width 14”
Case Width with Crown23 mm“Case w/Crown 23”

Visible details

  • Rectangular gold-toned tank case with subtly curved flanks and straight hooded-style lug ends
  • Dial exhibits severe all-over mottling, discoloration, and patina
  • Sub-seconds register positioned above the 6 o'clock marker
  • Printed black Arabic numerals and matching railroad minute track
  • Mounted on an articulated Speidel-style flexible expansion metal bracelet

Research qualifications

  • Movement and interior case back markings are documented by source description only and not visible in the provided photograph
  • The source text erroneously specifies the sub-second hand at the 'I o'clock position', whereas visual evidence confirms it is at 6 o'clock

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

1945 OMEGA Watch 17 Jewels Cal. R17.8 Tank Case Vintage Swiss Wristwat – SECOND HAND HOROLOGY

Reviewed 2026-10-21 · Record bb3aecda1c

Terms in this record

Glossary explanations for terms named in this object’s record.