The vessel depict on this stamp is not identified but she belongs to the Oder-type icebreakers built in the DDR to keep the river Oder open for shipping during the winter.
Altogether 6 were built from 1957/58.
Builders were the Schiffswerft Dresden-Übigau, who built the prototype, the other 5 were built by Thälmannwerft Brandenburg.
Dim. 30.10 x 7.35 x 2.20m. (draught)
Powered by a 6 NVD 48A diesel, 540 hp.
The names under which this vessel sailed or still sailing are:
ANGERMÜNDE, FRANKFURT, GARTZ, HOHENSAATEN, KIENITZ and ODER.
DDR 1981 35pf sgE2364 , scott?
Source: http://www.ddr-binnenschifffahrt.de/index.htm