"I decided I had to take a stand because I don't think Shell have the right to go into the Arctic and cause the potential damage that may happen up there.
"I just hope that other people are inspired to stand up for what they believe in...stand up for what's morally right and have a voice."
Mr Smith, who spent a week on the drilling rig, had said he had planned to be there "for the long haul".
"We can stay up here for as long as possible to get a message through to Shell and make more people aware of what is currently happening.
"They've decided to go and start drilling for oil in the Arctic and we believe that it is one of the most pristine, and one of last pristine spots in the world and it can't afford to have an oil spill."
The Polar Pioneer was one of two drilling vessels heading towards the Arctic for Shell this year - according to Greenpeace - and is being transported on a 217 metre heavy-lift vessel called Blue Marlin.
The Greenpeace ship Esperanza followed the rig for 5000 nautical miles since it left Brunei Bay in Malaysia.
Shell spokeswoman Kayla Macke said at the time that the protesters had "illegally boarded the Polar Pioneer, under contract to Shell, jeopardising not only the safety of the crew on board, but the protesters themselves".