"She had some beautiful qualities. She was frank, honest and a patriot. France meant something for her. Everyday she showed great tenacity an courage. How could you not be proud of her?" Muffat said.
"Dropped" involves contestants being left in the wilderness and using their skills to find their way back to civilization.
The collision marked the second time in two years that a reality show produced by ALP for TF1 had been hit by tragedy.
In April 2013 the doctor charged with looking after contestants in the long-running "Koh-Lanta" endurance show committed suicide after one of the competitors died following one of the tests, complaining of heart pains.
Arthaud, 57, was one of the first women to carve a place for herself in the top levels of sailing.
She had a brush with death in 2011, when she fell off her boat into the Mediterranean. Rescuers whisked her out after she called her mother by mobile phone.
Muffat, 25, won 400 meters freestyle gold at the 2012 London Olympics. Vastine, 28, won bronze at the Beijing 2008 Olympics.
"I am sad for my friends, I'm shaking, I'm horrified, I can't find the words," tweeted Sylvain Wiltord, an ex-footballer for English Premier League club Arsenal and a fellow cast member.