The Riddle of the Sands

The plot is complicated by esoteric sailing procedures, strange outdated social norms and some political intrigue. Set near the turn of the century just preceding the first world war. Michael York plays an English chart maker who stumbles upon suspicious activity along the German coast. He calls in an academic friend to assist him. Jenny Agutter is young and beautiful and we don't see enough of her in this. It's more than a bit dated now.