When you design a structural system, there are many considerations, among which is storage.
In the case of the workshop/crew cabin aft of the engine room, we are particularly interested in the bulk storage of engineering liquids. The framing system is laid out to efficiently store 20 liter/5 gallon containers. The area adjacent to, and aft of, the rudder posts can absorb 24 of these containers.
Forward of this, under the sole, is room for an additional eight to twelve containers.
Sounds like a bunch, but consider: two engines times roughly 30L/oil change times 5 oil changes equals 15 containers. Let’s add in a couple more for the genset, call it 18 20L pails. Now add four 10L containers of coolant, say two more for steering system hydraulic oil, and then four more 20L pails (minimum) of hydraulic system oil, and all of a sudden all that space under the swim step is close to full.
At the swim step level aft of the workshop are two large exterior lockers. Above, we are looking at the locker to port.
The spare props will store on the spindle. And above that there is a huge bulk stores area.
The flammable stores locker opposite can hold 18 of the 20L /5.3 US gallon containers.