Purpose-built landing craft carrier pioneering the concept of amphibious assault ships (modern-day LHA and LHD). Landing crafts can be launched via flooded well deck at the stern, hatches at the side and the fore main derrick (further readings via Wikipedia, Navypedia and Combinedfleet.com)
Please note forward main derrick arm located underneath/inside the hollow space of the hull; boom abaft mainmast not included (see Shapeways stock vs. my rendered image)