John McCarthy and Sandi Toksvig head further out into the Atlantic in order to reach the Outer Hebrides. Sailing at full speed up the Sound of Mull, they are suddenly engulfed by fog just as the satellite position finder stops working. On top of this, Sandi suffers a bout of asthma. After five weeks at sea, the strain of the journey is taking its toll.
Repeated tomorrow at 2.35pm