Lotte Hass.

Diver and undersea photographer.

Born: November 6, 1928;

Died: January 14, 2015.

Lotte Hass, who has died aged 86, was a diver and film-maker who, with her husband Hans Hass, became one of television's most famous underwater explorers. In the 1950s, she and her husband made a series of popular films for the BBC that made them household names in Britain.

Lotte Hass's achievements were particularly striking at the time. Initially, even her husband did not want her to accompany him on his diving trips because it was thought a woman would be too distracting, but Lotte persisted and became a skilled diver and film-maker and a female pioneer in a traditionally male-dominated filed.

She was born Charlotte Hildegard Baierl in Vienna and applied for the post of Hans Hass's secretary when she was 19 years old. She was due to start at university, but when she got the job with Hass, she changed her plans and went to work for him, much to her parents' displeasure.

When her new employer, who already had a reputation as a diving pioneer and underwater film-maker, began to plan a new expedition to the Red Sea, Lotte was keen to come along, but Hans was reluctant. Unbeknown to him, though, she took diving lessons and, while he was away, and went on a filming expedition to the Danube. The resulting pictures were published in an Australian magazine and greatly impressed Hans.

The film company on Hans' new project also recognised the appeal of including an attractive young woman in the film and encouraged Hans to include Lotte. The resulting trip was a great success, with Lotte and Hans filming manta rays and whale sharks. Their film, Under the Red Sea, won first prize at the Venice Film Festival.

On the return to Vienna, Hans asked Lotte to marry him, which cemented their long and successful personal and professional collaboration. Their first BBC programme, Diving to Adventure, which was filmed in the Aegean, was screened in 1956, followed two years later by The Undersea World of Adventure, which was shot in the Caribbean, Indian Ocean and the Red Sea.

In all, Hans Hass made 105 films and his wife co-produced and starred in many of them, although in 1960, after the birth of their daughter Meta, Lotte largely retired and concentrated on family life and refurbishing their apartment in Vienna.

In 2011, a TV movie, Girl on the Ocean Floor, was made about Lotte's life and work, based on her memoir of the same name. She is survived by her daughter and was pre-deceased by her husband.