In 1970, Tudor released its first Chronograph, the Oysterdate, with a manually-wound Valjoux mechanical calibre 7734 and cam chronograph function. Later in 1969 this was changed to a more ‘traditional’ alarm case with an external case back to increase its volume. 1957 saw the launch of the Tudor Advisor, which incorporated an alarm complication, the first Oyster model to amplify sound. In 1964, Tudor began producing an Oyster Prince Submariner specifically for the US Navy. Over the years the Submariner line adopted various features such as the 'big crown' and 'snowflake hands' (which have been reintroduced in for Tudor's current catalogue). Tudor launched its first diving watch in 1954, the Oyster Prince Submariner, waterproof to 100 metres, which increased to 200 metres in 1958. The French Navy was involved in field research for a Tudor diving watch from the 1960s to the mid 1980s, Tudor tool watches were supplied to the French Navy in bulk without bracelets so military-issued straps could be used instead. The adoption of the Oyster case and self-winding rotor facilitated Tudor's move into the production of tool watches. Twenty-six Tudor Oyster Princes were included in the British North Greenland expedition of 1952-1954. In 1952, Tudor released its first self-winding model, the Prince, which used a Rolex self-winding mechanism. Tudor debuted its Oyster collection in the mid-forties, featuring a waterproof Oyster case previously exclusive to Rolex. Tudor watches were originally equipped with off-the-shelf movements paired with Rolex cases and bracelets, allowing Tudor to provide reliability and quality while achieving its price goals. Tudor's purpose was to offer a more affordable watch than Rolex while maintaining Rolex-like quality. In 1936, Wilsdorf took it over and went on to found the company Montres Tudor SA in 1946. The Tudor trademark was registered in 1926 by Swiss watchmaking company Veuve de Philippe Hüther on behalf of Hans Wilsdorf, founder of Rolex watches. 1979 Tudor Submariner issued to the French Marine Nationale showcasing the brand's trademark 'snowflake' handset

Tudor black bay chronograph