A team of 20 employees and remote-controlled transporters moved the 1,221 tonnes of steel more than 100m across the shipyard. The hull section was then moved into position to line up with the rest of the block.
The two sections, which were brought together earlier in the week, form the midsection of the hull up to the hangar deck and are known as Lower Block 03.
Workers will now continue to outfit the block, which, on completion, will weigh more than 9,300 tonnes and stand more than 23m tall, 63m long and 40m wide.
It is set to embark on the next stage of its journey to Rosyth in the latter part of this year, where HMS Queen Elizabeth will be assembled in dry dock.
BAE is also constructing the main stern section at its yard on the Clyde, which the company said is the largest and most complex section of the carrier.
In Portsmouth, work is in progress to construct the forward and lower stern sections of the hull, as well as the pole mast, while integration and testing of the ships’ complex mission system is underway at the company’s Maritime Integration and Support Centre. Another team of BAE engineers on the Isle of Wight is testing the advanced communication systems.
The company is set to begin work on the two island structures, which house the bridge and traffic-control facilities, towards the end of the year.
Steven Carroll, Queen Elizabeth Class project director at BAE’s Surface Ships division, said: ‘Seeing the midsection of the carrier come together brings into sharp focus the sheer scale and complexity of this engineering feat.’