When Rimmer made contact with his brother Howard aboard the Columbus 3, he wanted to pretend that he was a captain so as not to be embarrassed when his more successful sibling arrived. To this end, he convinced the Boys from the Dwarf to masquerade as his senior officers. They put on the dead crew's uniforms and insignia and took their places on the bridge.
When Howard beamed aboard with Sim Crawford, Arnold explained that he was the ship's captain and proceeded to introduce his officers.
The Cat was renamed as Flight Officer Gerald Hampton, assigned as the ship's navigator, but he forgot that he was supposed to be playing a role and didn't respond to his new name until prompted several times. He was apparently hired as part of the Space Corps "Interspecies program". The Cat wore one of the snug, elasticated jumpsuits from the crew quarters.
Arnold descibed "Gerald" as being a very able pilot and navigator, which he then had to prove by changing course for the Alldroid space station. Since the Trojan was being towed by the Red Dwarf, the crew had to pretend to turn with the ship. (RD: Trojan)