Traditional surnames refer to things people do, characteristics of people, or the place from which they came. The Dubbelman name seems not to fit in. In the family are different stories narrated about the origin of the name. The statements are semantically, geographical or mytholigisch nature.
The name Dubbelman consists of two words. 'Dubbel' and 'man' in the current sense would be something like twice a man or someone who double stands his ground. An older (Germanic) meaning refers to the name of an important person, a 'dubbel' with a kind of hero status. The suffix "man" is an endearment and together it means something like 'beloved hero of the people. "
The river 'dubbel' once flowed where it is now the Biesbosch. A place Dubbelmonde refers to that river and was at its mouth. In the St. Elisabeth flood in 1421 disappeared Dubbelmonde underwater. The tradition in my family is that the people who went south from Dubbelmonde called themselves Dubbelmonders or Dubbelmen and then at last the name was just called Dubbelman.
A not actually verified geographical explanation of another family who find the explanation in the employers of a lord (possibly of Castle Maurik, which now lies drowned in the Biesbosch). These workers were called Dubbelmen. This designation would possibly be a corruption of Dubbelt Men who points out that these men received or were paying double rent.
In Russia, the name refers to a very strong person who was so strong that he was able to lift a horse up. Dubbelman is not written and does not sound like a Russian name. It may therefore be an English explanation of a double strong man ergo Dubbelman. The first Russian Dubbelman might have been the inspiration for this myth. He was propably Dutch.
Another explanation is that a hero came to the rescue of a child from a meadow with a raging bull. Double strong or beloved hero, Dubbelman.