A minor version of a captain's nightmare: in trouble with no hope of outside help.
The boat is bouncing on a sandbar because the captain tried to enter the harbor too long after high tide. When a wave lifts the boat off the bottom, the crewman tries to push it forward against the outgoing tide. The tide won, grounding the boat until lifted by the next incoming tide.
Given the small, diminishing swell and the boat's stout construction, the only damage was to the captain's reputation.
