The drinking water tank will be located under the berth in the port aft cabin. Fitting the floor and walls means the tank size can be measured and the tank ordered to fit the space.
The cabin ceiling creates a space above which will be used for lockers accessed from the side deck.
Electrical and plumbing service runs are planned and then the cabin walls are insulated and lined with plywood.
At the forward end the door opening is framed. There will be a hatch in the aft wall for light and as an emergency escape. The support frame for this is built into the bulkhead.