In the centre background is the floating dry dock holding the corvette HMAS Katoomba.
From the en.wikipedia.org
Down at the end of the quay, in a floating dry dock, is the Cambria, a 92ft Thames sailing barge, the last British-registered vessel to carry a commercial cargo solely under sail.
From the guardian.co.uk
The floating museum will go into dry dock in October for upgrades and repairs.