Britain and the Sea earlier but something more interesting came up.
I can't remember exactly what it was - maybe washing, or was it cooking? - for the problem is there isn't really enough meat in Dimbleby's show to keep one's attention focussed on whatever it is meant to be about.
I remember reading a review of the show asking what was the point? Or, to be a bit more accurate, "where is it going?", as the key thing about a TV documentary is to identify what it was meant to achieve.
Keep the focus must be a good message, as can be seen in another BBC documentary which is also about Britain and the sea though with a tighter remit.
In a program with a title like Shipwrecked: Britain's Sunken History you won't head off on tangents (such as Dimbleby's tours of an old castle's surprisingly boutique bathroom) but can expect some good stuff about the Spanish Armada, Shakespeare's Tempest, the castaway Selkirk and how a staggering one in five ships in the great age of explorers never came back.
A definite high spot was "Navigator and maritime adventurer" (what a great intro) Tristan Gooley showing how to measure your speed with knots and the latitude with a backstaff: