Yes the black line is the waterline and there is more ballast on the first picture.
The hull is in GRP and I've made a master with wood and foam.
Then there is three hull with different length for two friends and me - We don't want to reproduce a real ship and prefer free lance but looks like ones ! The largest (around 2 meter) will be a like Island Constructor with derrick and helo deck. The medium one (1.85 meter) will be an Anchor Handling Tug Supply close to the Bourbon Orca. the shorter one (1.78 m) is mine and also will be an AHTS but not like the Bourbon Orca (ROV capacity - regular props ....)
The X1 (larger hull) and the mould
The X1 (larger) and the X2 (medium) the middle part (without form like a cylinder is removed)
Inside the mould prior the X2 construction - in fact there is two serarate parts moulded and then both part are "welded" later.
As the keel and aft part are different from ship to ship, each modeler built his own