As is usually the case, the optimum tackle to use for thornback rays will be dictated by the ground you are fishing.
Given that the species is especially common throughout the lower reaches of estuaries and sand, mud and shingle banks, areas that invariably are subjected to a fast run of tide, uptiding is a popular technique.
Generally, uptiding rods must be capable of casting 4-8oz sinkers and your bait away from the boat, with the power to handle big fish in fast tides too. Match your rod with a casting multiplier, such as the Shimano Torium 14 or Abu 6500/7000, or strong fixed-spool reel loaded with 18lb mono line.
In deeper water, fishing downtide is also very effective. You may be able to get away with a 12lb-class rod, but strong tides often require a 20lb or 30lb-class version. Use a lever-drag multiplier, such as the Shimano Charter Special TR1000LD, loaded with 20lb braid. In places with stronger tide, you may need 30lb braid.
For the more adventurous fishing in places like the Thames Estuary, it’s possible to fish light, such as a 10-40g spinning rod and fixed-spool reel loaded with 20b braid for both uptiding or downtiding.