Curly Blonde Girl With A Hat In The Boat On The Lake

An enclosed space on a boat is referred to as a cabin. Several structures make up a cabin: the similar but usually lighter structure which spans a raised cabin is a coach-roof. The "floor" of a cabin is properly known as the sole, but is more likely to be called the floor (a floor is properly, a structural member which ties a frame to the keelson and keel). The vertical surfaces dividing the internal space are bulkheads.
The keel is a lengthwise structural member to which the frames are fixed (sometimes referred to as a backbone).
The front (or forward end) of a boat is called the bow. Boats of earlier times often featured a figurehead protruding from the front of the bows. The rear (or aft end) of the boat is called the stern. The right side (facing forward) is starboard and the left side is port.