The float turned out scarier than anticipated, Silver-Vallance said afterwards.
A change in wind speed and direction threw a spanner in the works.
"I was going up … then I started coming down again, that's when it got hairy again," said Silver-Vallance.
South African born Silver-Vallance, who is a medical industry professional, landed safely after floating from Robben Island to the mainland using a cluster of helium filled balloons.
He carried out the stunt in an attempt to raise R10-million for the building of the Nelson Mandela Children's Hospital.
Higher than expected
Due to wind conditions, Silver-Vallance had to let the colourful array of balloons go as he was pulled in by sea rescue vessels and rubber ducks earlier than expected.
He fell onto a rubber duck and was not far from his target. He was meant to land beyond the breakers.
The plan was to use 200 balloons but after expert advice Silver-Vallance took off with 160 balloons.
The balloons floated to higher altitudes than expected, making the man dubbed 'Balloon Bloke' a little nervous.
"I got to about one thousand feet [above sea level], about the height of Table Mountain," he said.
Silver-Vallance tried to pop some balloons but the pellets just bounced off them.
He had to resort to spearing about 35 balloons, leaving him exhausted.
Pulled down
Silver-Vallance eventually dropped a rope and was pulled down to a sea rescue craft following his trajectory.
He waved excitedly at journalists in a navy vessell, as the rubber duck he was travelling in passed by.
The navy sounded four fog horns to congratulate him for his achievement.
His feat was not a complete failure as his landing place was only a few hundred metres from where his balloon journey was meant to end.
Asked whether he was disappointed, he said he was just glad to be safe.
He did however add: "Would we do it again? Probably not."
Silver-Vallance said he and a few others were planning "something a lot more fun" but would not elaborate.
He said he did not know how successful his main mission to raise money for the NMCH was but at an earlier count at least R70 000 had been raised.
"That was what it was all about … for people to spend five minutes on their laptop and make a donation." – Sapa