John and Michael's first task is to cross the Thames estuary, where they discover a genuine Dunkirk rescue boat and are challenged to eat oysters gracefully.
The duo embark upon the second leg of their voyage. Missing the morning tide in Portsmouth they visit HMS Victory before sailing to Cowes. They then make their way past the Needles to Poole.
Michael and John face their biggest challenge. In sole charge of the Bonaventure, can they make it safely from Falmouth to Brixham? But first, they must decide who is to be captain.