FitzRoy knew that commanding a ship could involve stress and loneliness. He was aware of his uncle Viscount Castlereagh's suicide due to stress from overwork, as well as Captain Stokes's suicide. This was to be the first time that FitzRoy would be fully in charge of a ship with no commanding officer or second captain to consult. It has been suggested that he felt the need for a gentleman companion who shared his scientific interests and could dine with him as an equal, although there is no direct evidence to support this. Professor John Stevens Henslow described the position "more as a companion than a mere collector", but this was an assurance that FitzRoy would treat his guest as a gentleman naturalist. Several other ships at this period carried unpaid civilians as naturalists.