The orange areas are flotation compartments; the black areas are water-ballast tanks.
RoG - Small Boats Monthly
Bateau.com user built boat gallery - boats/FL12
The cabin provides sitting headroom and a table for dining and navigation. The RoG's designer, JF Bedard, takes a look here at a chart of Florida Bay.
The cabin can sleep two. Note that the oar handles extend into the cabin.
Running wing-and-wing, the Rog shows the open transom that makes the cockpit instantly self-draining.
When the oars are not needed they can be stowed out of the way under the starboard deck. The cover for the access hatch is retained by an internal bungee cord.
Working in light air and in the lee of islands, the oars can be kept in their locks, ready for rowing when the sails aren't filled.