Had such an encounter at Castries (St Lucia) involving a very large cruise liner.
The evolving pace of the event was sufficiently slow to debate if steam should give way to sail - aircraft depending on air, or if the minimum miss distance constituted a notfied approach hazard.
Increasingly obvious that the situation would be a DH, lateral and vertical, took the opportunity to view the ship and a tour of the harbour from a safe height.
As I recall, one of the Amsterdam runways required a change of landing minima if a barge was reported on the canal within the approach lights.