No 4 Dock, including bollards and capstans

No 4 Dock, built between 1796 and 1797, is one of four dry docks made of granite and limestone ashlar. It is oriented on a north-east to south-west axis, with the dock mouth facing west towards the Hamoaze estuary.

The dock features altars that step down towards the center, with slides and steps around the sides for moving materials. The walls of the dock are rounded at the heads, and there are pedestrian steps leading down to the lower dock levels. The walls are marked at intervals with Roman numerals indicating the water height. As of 2015, there is no evidence that the iron gates, which were present in 1999, still exist.

Cast-iron bollards line all four docks, most of which are from the late 19th century and inscribed with the letters VR, with some dated 1897. Upturned muzzle loading cannons have also been repurposed as bollards. Hydraulic capstans, dated 1897, are located on either side of the dock gates to No 4 dock.

Several features within the dock area, such as metal barriers made from reused railway tracks, chain link fences, life ring stands, and metal security fencing, do not contribute to the special interest due to their late date and plain design. Additionally, fragments of early 20th-century dock rail track are not considered of special architectural or historic interest.