Kalev class submarine Estonia

Either the Estonian submarine EML Kalev circa WW2.

Estonia did have a submarine in 1937! Finnish–Estonian defence cooperation was the mainstay of defence plans in the 1930s and 1990s. The Estonian submarines Kalev and Lembit were imported from the UK due to the lack of native industry in Estonia. Both had been manufactured in the UK and began their military service in spring 1937.

Sources- [1] and [2].