Complex sentence: The Thames skiff owes its origins to the clinker boat building technique, of over-lapping timber planking, that's known to have existed in the region from before the 6th century Anglo-Saxon Snape and Sutton Hoo ship burials.
Split into simpler sentences: The Thames skiff owes its origins to the clinker boat building technique, of over-lapping timber planking. That's known to have existed in the region from before the 6th century Anglo-Saxon Snape and Sutton Hoo ship burials.