Drawing by Tapani Tuomanen
In 1938, the VVS VMS (Navy Air Force) required a seaplane version of the DB-3P to operate on the White Sea and Barents Sea and on the Pacific Ocean, where they lacked of sufficient shore based airfields.
A standard narrow-canopy DB-3 was converted into the DB-3TP (Torpedonovyes Poplavkovyj, Torpedo Float Plane) in early 1938. Two British-built floats replaced the retractable landing gear.
The plane was provided with a T-18 pylon for a 45-36-AN or 45-36-AV torpedo or a 900 kg mine, plus two side pylons for 400 kg of bombs. It was predisposed for the same defensive armament of usual DB-3s (3 ShKAS), that never appears on photos and probably was not installed during the tests. It was povered by two M-86 engines driving co-rotating V-85 propellers.
The prototype was flown by test pilot V.K. Kokkinati in early 1938 and found satisfactory, and a first batch of 15 was ordered, but the operative tests of the prototype in summer 1938 in the Black Sea revealed a lot of difficulties in loading weapons, maintenance of engines etc, for which the plane required specialized hangars; besides the plane was 27 km/h slower than the usual DB-3.
So, the production order was deleted, and it was preferred to increase the number of bases for traditional torpedo planes.
The plane was painted light grey overall (a low-quality precursor of the AE-9
paint), with red stars on the fuselage sides, and on wing upper and undersurfaces
according to the prewar use.