These light transports were derived from the earlier F13. Indeed the prototype was a converted F13 with a lengthened fuselage and more powerful engine, but with the fixed undercarriage retained. The W33 and W34 came in ski and float versions and copious other variants. There were nearly 200 W33s built, but the W34 totalled nearly 1800 examples, which were extensively used by civil operators. A total of 900 saw service with the Luftwaffe as trainers and transports during World War II. A W33 made the first east-west Atlantic crossing in 1928 from Dublin to Labrador.