The crane barge planned to lift the remainder of the Rena's accommodation block during recovery operations is now surplus to requirements and will head offshore next week.

Spokesperson for the ship's owners and insurers - Daina Shipping and The Swedish Club – Hugo Shanahan says the Resolve RMG 500 is expected to leave after plans to remove the second part of the sunken aft section were abandoned.

The Resolve RMG 500 barge. Photo: Tracy Hardy.

The Port of Tauranga schedule says the barge has been docked in port since June 14 and will depart next Friday. SunLive understands the crane barge is headed for Singapore.

A sonar survey earlier this year confirmed the underwater aft section had moved slipped further down the reef after Cyclone Lusi leaving it in a risky salvage position.

Hugo says the survey undertaken after the March storm shows the section of hull has moved on the face of Astrolabe Reef and the remaining accommodation block section now lies in water 24m to 53m deep, beyond depths typically accessed by recreational divers.

Instead Resolve continues to reconfigure the large RMG 1000 barge to resume operations to further reduce the debris field, which covers the area of seabed between the bow and aft sections, and alongside the wreck to a depth of about 30m.

A second crane is being added to the RMG 1000 for the operation, and a hydraulic grab will be used to recover debris, including parts of the ship structure weighing up to 10 tonnes.

Once the grab can no longer recover sufficient amounts of debris effectively, divers will re-assess the state of the debris field to identify and target specific areas that require further work.

Hugo says this stage will involve the use of dive teams and possibly a powerful magnet where debris will be sorted into three categories of steel, aluminium and non-metallic refuse before transporting to shore for recycling or disposal.

Resolve has now removed a 600-tonne port side piece, which has been recycled back in port.

Divers have also surveyed the area underneath where the piece lay, successfully recovering about 800kg of remaining plastic bead cargo.

The container ship Rena struck Astrolabe Reef at 17 knots early on October 5, 2011. The ship later broke up spilling heavy fuel oil and cargo into the Bay of Plenty. The oil and some of the containers washed up along the beaches.

With the removal of that section no longer pursued it now forms part of the resource consent application proposal to leave the Rena section on the reef filed with the Bay of Plenty Regional Council.

Hugo says current weather forecasts indicate work should resume today with both the Resolve Gladiator tug and Commander tug to leave port on that day.

The RMG 1000 is not scheduled to leave until Thursday.