A Ministry of Defence team is due to restart work on removing oil from the wreck of the Royal Oak in Orkney.
The experts hope to be able to extract oil from two inner tanks which have lain untouched for decades.
There could still be a substantial amount of fuel still in the wreck in Scapa Flow.
The navy increased efforts to reduce the flow since the amount of oil leaking from the ship soared some 10 years ago.
This week the team will concentrate on previously inaccessible inner tanks which they think still contains a substantial amount of oil.
They developed the hot tapping system which allowed them to attach valves to the tanks.
The work is dangerous as there is still live ammunition on board but a sonar survey of the vessel shows the wreck is very stable and sturdy considering her age.
They will also remove oil from two well known areas where it has leaked from for several years.
The work is expected to take about two weeks but the MoD says that it is committed to carrying on the work for the foreseeable future.