Early on the morning of April 30, 1969, the Hannes Knuppel collided
with the tanker Hamilton Trader in Liverpool Bay in the Irish Sea.
The Hamilton Trader was anchored near the Bar Light Vessel at the time of the collision.
A starboard tank on the Hamilton Trader was holed
and approximately 4,000 barrels of No. 6 Fuel Oil was spilled.
The spilled oil impacted approximately 50 miles of shoreline.
Cleanup was accomplished primarily with chemical dispersants on the oil slicks at sea.
No. 6 fuel oil is a heavy product with an API gravity that ranges from 7 to 14.
At around 1500 April 30, a Lancashire and Western Sea Fisheries vessel
reported a three-mile long slick extending southwest of the collision site.
On May 1, a slick six miles long extended to the northeast.
On May 2, the slick was 3 miles long by 2.5 miles wide and was 9 miles north of Rhyl, Wales.
The slick had dispersed somewhat by this time.
The oil moved west to a point 10 miles north of Great Orme Head, Wales and remained there for two days.
By May 7, the slick was 20 miles long and extended from 10 miles off Colwyn Bay to Red Wharf Bay.
Oil was driven to the north, and came ashore on May 11.
Three miles of beaches near Selker Bay, England were oiled.
By May 21, the oil had impacted various English beaches as far north as Allonby in the Solway Firth.
A total of 50 miles of shoreline were affected.