Coastguards are urging better training standards at sea after the master of a coaster was prosecuted for endangering other ships in the Dover Strait.
A computer image showed coastguards the ship's erratic course
Ukranian Yuri Moskalenko, 40, was fined £2,000 and ordered to pay £1,500 costs over the incident on New Year's Day.
Magistrates heard how he constantly altered the course of his ship during a period lasting nearly three hours.
Dover Coastguard Peter Legg said it was the most dangerous incident in the English Channel for nearly 30 years.
The Panamanian-registered Dreamer 1 had left Kings Lynn on 31 December with a cargo of scrap bound for Plymouth.
Mr Legg tracked the 1,600-ton vessel's meandering course on a computer as it passed through the Dover Strait and then made radio contact with Moskalenko.
The skipper claimed his ship had suffered a steering gear failure but officials dismissed claims that it was "safer" to continue rather than stopping the vessel to sorting out the problem.
The erratic vessel was eventually apprehended near Dunkirk, and taken to Plymouth, where the skipper was arrested.
At Plymouth magistrates on Friday, he pleaded guilty to endangering life.
Mr Legg described it as a dangerous situation "which had had tremendous potential to be actually disastrous".
He said coastguards were looking towards better training standards at sea for all nationalities and all companies operating vessels, particularly through the Dover Strait.