I cannot answer your question based on the man's uniform, but the scene and the order to send women and children to the Boat Deck is reminiscent of Third Class Steward John E. Hart. He survived and his testimony at the British Inquiry is available here. Note that some here have questioned the authenticity of Hart's story, but he does testify that he went down to Third Class and ordered women and children to come to the Boat Deck. Some willingly stayed behind, and undoubtedly some did not understand the order given in English.
That's Desmond Llewelyn, best known as 'Q' in the early James Bond films. In the imdb cast listing he appears as an uncredited seaman (which is clearly wrong) but in the most detailed available cast list he appears as an uncredited steward. I have also seen a reference that he was playing one of the two Masters at Arms. Whatever, it's unlikely he was intended to be any particular identifiable individual. Take your pick.
He has what casting directors would have classed as a generic southern English working class accent. Like most of the bit players in ANTR, he is representative of a type rather than an individual - in this case a 'jobsworth' crew member who doesn't really know what's going on.