| Name: | UNNAMED |
| Type: | Caisson |
| Launched | n/a |
| Completed: | 1867 |
| Builder: | J Wigham Richardson & Co |
| Yard: | Neptune Yard, Low Walker |
| Yard Number: | 46 |
| Dimensions: | 120grt |
| Engines: | None |
| Engines by: | n/a |
| Propulsion: | None |
| Construction: | Iron |
| Reg Number: | n/a |
| History: | |
| 1867 | Millwall Dock Co, London |
| No later history known | |
| Comments: | A caisson for the dry dock inside the Millwall Dock |
| Caisson was held in place by the pressure of water in the main dock | |
| 1922: Replaced by a new one from Swan Hunter at Wallsend |