Piaggio designed the P.23M specifically for flights across the North
Atlantic Ocean, intending it to have potential for development as a commercial
transport. It was a four-engine shoulder-
wing monoplane with inverted
gull wings and twin tail fins and
rudders. To allow an easier landing if the aircraft had to ditch at sea, its
fuselage was designed like a boat
hull, which Piaggio termed an
avion marin ("marine aviation") design, although the aircraft was not a
flying boat. The main
landing gear was retractable. The P.23Ms four
Isotta-Fraschini Asso XI R. V-12 engines were mounted on the wings in two tandem pairs, each engine driving a two-bladed
propeller; two of the propellers were mounted in a
pusher configuration and the other two in a
tractor configuration. Piaggio claimed a top speed of for the P.23M and projected its maximum range at a cruising speed of as . ==Operational history==