Erg was built at the Halifax Shipyard in 1915. The steam tug was first named Sambro and during the Halifax Explosion on 6 December 1917, while docked at the Graving Dock Wharf on the Halifax side of the harbour, sank to the bottom of the harbour from the force from the explosion. It is not known if there were any lives lost. The Explosion occurred 980 feet north of the Graving Dock and many yard workers were killed. Sambro was raised from the water in 1927 and renamed Erg.
During the Second World War the vessel assisted with the movement and repair of larger ships. On the morning of 6 July 1943, Erg was carrying workers and equipment on its way to service a Merchant Navy ship that was anchored in the Bedford Basin with an assembled convoy, and was hit by the Norwegian freighter SS Norelg, a larger ship weighting in at 3,382 tons. Erg was struck from behind, crumbled on the port side and completely tipped her over, sinking within six minutes. There were 24 men aboard and only five survived. A few escaped through the only exit door leading from the wheelhouse and the other nineteen men were trapped in the wheelhouse and the engine room below the deck.
On 19 July 1943 the Royal Canadian Navy raised Erg from the water and it was beached on the eastern side of the Bedford Basin. There they were able to recover ten bodies, but the other nine were never found. Erg's hull was too badly damaged to repair, so was taken to shallow end of the basin in Roach Cove and scuttled and sunk for the third and last time on 24 August 1943. A plaque was presented by the Halifax Shipyard during a ceremony to honour the lost workers.
Nova Scotia Underwater Exploration Society divers found the wreck in October 2000. The sunken vessel was described as being fully intact, sitting perfectly upright with its dented wheelhouse also sitting upright and its propeller still attached. The Erg’s back was broken with its back end slightly sticking up in the air. The divers were able to go inside the wreck and swim around viewing everything. The site was proclaimed a Protected Heritage Site under the Special Places Protection Act and divers placed this plaque beside the wreck.
