The brief for Top Dogs: Adventures in War, Sea and Ice was to take three of Britain's greatest adventurers and get them to experience the different environments where each found fame and glory, as a team.
The first trip took the three men - Ranulph Fiennes, the polar explorer, John Simpson, BBC world affairs editor, and Robin Knox-Johnston, the first person to sail single-handed around the world - to war-torn Afghanistan, Simpson's world. The third involved trekking in the Arctic, Fiennes' domain.
I was charged with the second trip, which focused on Knox-Johnston's area of expertise. It involved sailing around Cape Horn, in the treacherous Southern Ocean. Even with an experienced sailing crew this would be a challenge. But Ran and John had never sailed before, so we had the ingredients for an exciting, even risky film.
The "top dogs" trained in the Solent to use life rafts, flares and survival suits. The production team learned how to use a defibrillator: Ran had a major heart attack a few years ago. If he had another on this trip it would be up to us to keep him alive.
Top Dogs:Adventures in War, Sea and Ice is a BBC Wales production for BBC2. It starts on 27 March at 9pm.
To read the rest of Ben Duncan's experiences On Location see the 27 March issue of Broadcast, out Thursday.