Heres one of my occasional challenges to you all, as i’ve currently been unable to find any information on this boat or when it sunk.
It can be found at low tide at the entrance to Middlesbrough Docks, right next to the football ground.
Sunken Boat, Middlesbrough Docks

It looks like an old dumb barge, similar to the one that can be seen in the sand at low tide on Bran Sands.
I agree with Andy, or could it be a former ships lifeboat that had been converted ?–just a thought ! surely PD ports as successors to the Tees Conservancy Commissioners might have a record.
Judging by the beam it is definitely a barge
Both ends seem to have had a substantial deck at some time, is that a clue ?
A look at Google images came up with a Thames lighter which is very similar and some of the old aerial photos o the docks seem to show similar craft.
The wreck is a discharge barge or dumb hopper. The site was investigated in 1995 and an early 19th century pilot cobble was excavated and removed from the site. There is also a 36m long wreck of a dredger the ‘Tees’ which sank in 1908 and was never salvaged.
Further reading shows that the ’19th century pilot cobble’ turned out to be a 1944 Admiralty Whaler