Preparations are under way for the removal of masts from the SS Richard Montgomery in the Thames Estuary.
Vessels have been seen near the explosives-filled World War Two ship wreck site, which is visible from Kent and Essex since the US military vessel sank in 1944.
The Department for Transport previously confirmed work would start in September to remove the masts in case they fell on to and detonated 1,400 tonnes of explosives that remain within the ship.
Engineers will work underwater to cut the masts off the shipwreck.
The artefacts will be conserved at Chatham Historic Dockyard after a campaign for them to stay in Kent, as they are technically the property of the US government.
The shipwreck, which has become a draw for tourists, is located about 1.5 miles off the coast of Sheerness.
Efforts to salvage the cargo vessel, known as a Liberty ship, in 1944 were abandoned when it flooded about a month after it ran aground.
The salvage project, first announced in 2020, is estimated to cost £9.5m.
