All Fortis

Fortis

Fortis Marinemaster 43 mm Blue Carbon

Photography on request

Front view

Front view

Dial, hands and bezel as delivered.

Case-back view

Case-back view

Case-back engraving and, where fitted, the sapphire display.

Movement

Movement

Calibre with its finishing and decoration.

On the wrist

On the wrist

Worn shot for proportion and strap drape.

Fortis · Marinemaster

Fortis Marinemaster 43 mm Blue Carbon

Reference 83930OR.85

Reference at a glance

Brand
Fortis
Collection
Marinemaster
Model
Fortis Marinemaster 43 mm Blue Carbon
Reference number
83930OR.85
Year / era
1957 · 1950s — pre-quartz mechanical era
Complication
Moon phase
Movement
Automatic COSC chronometer
Case material
Carbon TPT
Dial type
Blue "Grande Tapisserie"
Strap / bracelet
Milanese mesh
Water resistance
300 m
Limited-edition status
Regular production, not a limited edition
Compare this reference

Case, dial & bracelet

Case dimensions
43 mm
Case thickness
14.1 mm
Case material
Carbon TPT
Bezel
Smooth polished
Crystal
Anti-reflective sapphire, double-domed
Dial
Blue "Grande Tapisserie"
Hands
Mercedes hour hand with Chromalight display
Indexes
Printed minute track with applied batons
Bracelet / strap
Milanese mesh
Clasp / buckle
Pin buckle in matching case metal
Water resistance
300 m

Movement

Movement / calibre
Calibre 53F — Automatic COSC chronometer
Movement type
Automatic, self-winding
Frequency
21,600 vph (3 Hz)
Power reserve
5 days
Number of jewels
33 jewels
Complications
Moon phase
Functions
Flying tourbillon, power reserve
Watchmaker
The calibre is built in-house and adjusted in five positions before delivery.

Production & market

Production period
1957 – 1967
Limited-edition quantity
Not applicable
Current market information
Values have stabilised after the 2022 correction; condition and box-and-papers drive the premium.

Designer

Gérald Genta

Gérald Genta (1931–2011) trained as a goldsmith in Geneva and became the most influential watch designer of the 20th century. Working freelance, he sketched the Audemars Piguet Royal Oak overnight in 1970, followed by the Patek Philippe Nautilus, the IWC Ingenieur SL and the Bulgari Bulgari — defining the integrated-bracelet luxury sports watch as a category.

Historical significance

Fortis Marinemaster 43 mm Blue Carbon sits within Fortis's Marinemaster line, introduced in 1957. It carries the house codes established since 1912 — carbon tpt case, blue "grande tapisserie" dial and automatic cosc chronometer — and is one of the references collectors use to date the evolution of the collection.

Interesting facts

  • The movement's bridges are decorated even where they will never be seen once the watch is cased.
  • The bracelet tapers across its length, which is why the profile looks thinner on the wrist than the specification suggests.
  • The reference was originally planned as a one-year run and stayed in the catalogue for well over a decade.
FO

The House

Fortis

Brand facts

Founding year
1912
Founder
Walter Vogt
Headquarters
Switzerland
Tier
Affordable & Tool Watches
Major collections
Flieger, Marinemaster, Stratoliner, Novonaut
Signature technologies
Shock-absorbing movement mounting · Certified chronometer regulation · Hand-applied guilloché dials
Famous movements
Automatic COSC chronometer · Automatic, 38-hour reserve · Automatic Powermatic 80 · Quartz
Notable watches
Fortis Flieger 43 mm Silvered Sapphire (1970) · Fortis Flieger 37 mm Green Grade (1978) · Fortis Flieger 42 mm Silvered 18k (1966) · Fortis Flieger 38 mm Meteorite Grade (1974)

Brand history

Fortis has spent more than 114 years refining a single idea: a watch should outlive its owner. From the earliest workshop pieces to today's Flieger, the house has balanced technical ambition with a recognisable design language, and its collections remain among the most closely followed by collectors worldwide.

Walter Vogt established Fortis in 1912, working from Switzerland at a time when precision was measured by hand. The founder's obsession with finishing and accuracy still defines every Fortis calibre produced today.

Historical milestones

  1. 1912

    Walter Vogt founds Fortis in Switzerland.

  2. 1969

    The quartz era forces Fortis to redefine mechanical watchmaking.

  3. 1990

    Fortis enters the modern collector market with its signature lines.

  4. 2024

    Fortis continues to produce Flieger, Marinemaster, Stratoliner and other icons in limited numbers.

More Marinemaster