This is the presumed site of the Leithead family shipyard, which operated between around 1844 to around 1857.

The Leithead's shipbuilding on the Wear commenced closer to the sea at Low Street, Bishopwearmouth in 1827. There, Andrew would stay for 6 years until a later move to the North Sands through to 1844. From 1844 ships were built on the south bank of the Wear at Pallion, though there's plenty of contestation between the specific location with some sources even referencing Arrow built at Southwick. However, all newspaper sources point to the site being at Pallion, and was probably one of the many along the quayside facing Southwick west of the Queen Alexandra Bridge today.

The Leithead's were a border family from Eccles on the Scottish side. Arrow appears to be the son of James with Andrew appearing to be a cousin of sorts (best explained by Searlecanada - https://www.searlecanada.org/sunderland/sunderland068.html).

At least 27 vessels were built at the Leithead yard, all for general cargo merchants across the North Sea, the Mediterranean and even to Australia. In fact, there's some fantastic shots of the Trafalgar owned by Duncan Dunbar in the 1860s here: https://commons.wikimedia.org/wiki/Category:Trafalgar_(ship,_1845). Ships were very likely built on scaffolding placed onto the quay, then shuffled into the water upon completion - Kind of like the side launches you still see today.

Most of the ships were built in partnership between Andrew and Arrow, right through to 1850 when the partnership was dissolved. From there, Andrew built over the river at Southwick which may explain the confusion cited in the previous paragraph. Arrow remained here until 1857, the year when the Doxford's moved into the area from Hylton. Eventually, they absorbed the whole area making it unrecognisable from these times.