Pomorac was built in two halves. A two ship contract from Hong Kong, the contract was cancelled while the ship was under construction. This disruption to the building programme made A&P launch the aft end. Later, the fore end was launched and the two halves joined at Brigham and Cowan.
In the 1960s two 45,000 Dwt bulk carriers were built in two halves.
"Sygna" and "Happy Dragon" were both built at Austin and Pickersgills, Southwick yard and joined together on the Tyne. Sygna grounded off Australia and broke in two.
I THINK that the reason for two halves was the acute bend in the River Wear at Deptford (Laings yard), was such that ships of that length couldn't get around it, though the narrowness of the river at Southwick would also be a consideration for launching.