The Delphin I was developed in 1920. It was an all-metal single-engine high-wing monoplane flying boat. It had an enclosed cabin for four-passengers with the wing mounted above and the nacelle-mounted engine above that. It was powered by a 138 kW (185 hp) BMW IIIa inline engine. The pilot had an open cockpit on the upper surface of the hull behind the engine which gave him a limited view forward. It first flew on the 24 November 1920.
Type Do Cs II 1 + 5 passenger carrying flying boat Do Delphin I 2+ 6 passenger carrying flying boat Do Delphin I 2 + 6 passenger carrying flying boat
Engine 1 BMW IIIa 1 BMW IIIa 1 Isotto Fraschini A 10
Dimensions Length 10.25 m, height 2.75 m, span 17.00 m, wing area 47.00 m2 Length 11.50 m, height 3.10 m, span 17.10 m, wing area 51.30 m2, cabin: length 2.65 m - height 1.60 m - width 1.25 m
Weights Empty 1350 kg, load 650 kg, flying weight 2000 kg Empty 1600 kg, load 600, fuel 200 kg,oil 15 kg kg, flying weight 2200 kg
Performance Max. speed 150 km/h, cruising speed 120 km/h, service ceiling 4000 m, range 450 km Max. speed 125km/h, cruising speed 110 km/h, service ceiling 4000 m, range 660 km
Type Werk.Nr Registration History
Cs II, Delphin I, Do L Bas 21 A-6055 Built in 1920 at Seemoos and Rohrschach. First flight 24/11 1920 (Pilot Lesch).  Modified with a longer bow after a landing mishap, named Delphin I after this change. Sold to the US Navy in 1921
Delphin I 25 Built in 1921 at Seemoos. Modified with an even longer bow. Sold to Fa. Kawasaki Dockyard Co. Ltd., Kobe/Japan. Delivered with 1 Rolls-Royce Eagle
Delphin I 26 Built in 1921 - 24 at Marina di Pisa, Italy. Tested with an Isotto Fraschini A 10
Delphin I, Delphin II 27 Built in 1921 - 24 at Marina di Pisa, Italy. Delivered back to Seemoos, equipped with 1 Rolls-Royce Falcon as a Delphin II (New WerkNr. 110 ? ).First flight 15/2 1924. Used by the Bodensee Aero Lloyd. Crashed at Lindau (Pilot Stroebel)