Lihue, Hawaii ? The water was clear and there was no indication of danger when a 13-year-old surfing star went out on the waves with her best friend and her friend’s father.

But while Bethany Hamilton was lying on her board off Kauai’s North Shore, a shark bit once and then disappeared, taking off her left arm just below the shoulder.

“Nobody saw it happen. She just yelled, ‘A shark bit me!”‘ said her father, Tom Hamilton.

Tom Hamilton said his daughter was conscious and alert and in stable condition after the attack Friday morning. Doctors at Wilcox Memorial Hospital said her top condition as a competitive athlete helped her survive the attack.

Bethany, of Princeville, was attacked in an area known as Tunnels a quarter-mile off Makua Beach near Haena.

Bethany was surfing with best friend Alana Blanchard, also 13, and Alana’s father, Holt Blanchard, her family said.

Blanchard immediately applied a tourniquet to Hamilton’s arm using a surfboard leash, the family said.

After the attack, lifeguards from Hanalei went out on personal watercraft to warn people in the water, said Cyndi Ozaki, spokeswoman for Kauai County. Officials also closed the area between Ke’e and Wainiha beaches.

“The water was crystal clear according to people in the area, and there was no indication that there was a shark nearby,” she said.

The shark took a chunk out of Bethany’s surfboard that measured about 16 inches across and 8 inches deep, penetrating nearly to the center of the board, which suggests the shark was 12 to 15 feet long, Kauai fire Battalion Chief Bob Kaden said. It may have been a tiger shark, said Randy Honebrink, spokesman for the state Shark Task Force.

Bethany is a competitive surfer who already had secured sponsorships and was expected to go pro, according to the Hanalei Surf Online Web site.

In August, she won the explorer women’s division of the National Scholastic Surfing Assn’s Open and Explorer event on Kauai.