On the beautiful British waterways an inexperienced narrow-boater is pursued by a malevolent, murderous barge as she reluctantly cruises upriver alone to sell her Grandpa’s boat.

Leaning towards:
“A novice captainess must escape a malevolent barge when traversing the British waterways in order to sell her grandfather’s narrowboat”

Hope this helps, keep going!

Sounds like Duel on water. I like it.

Title of this 90min Feature: Boating for Beginners