What appeared to be a harrowing story of survival emerged from Suisun Bay on Monday - that of a wayward rafter who spent five days stranded on a deserted island nibbling on vitamins and native plants and fashioning a crude "SOS" sign until the U.S. Coast Guard rescued him.

But after returning to shore, Brian "Goat Man" Hopper added a twist to the tale. He admitted that he failed to make use of a key piece of equipment during his stay on Roe Island north of Concord: a cellular telephone.

"I was embarrassed to be stranded on an island," Hopper, a 54-year-old artist from Encino (Los Angeles County), told The Chronicle. "I thought I could fix my boat and make it to land. ... I didn't want to spend the taxpayers' money to have the Coast Guard come rescue some stupid guy."

But on Monday morning, the Coast Guard did collect Hopper on a 25-foot boat after receiving a call from one of his friends - a man Hopper had telephoned directly.

Rescuers pieced together clues from Hopper - that he could see Naval vessels and could hear reveille, a military bugle call, every morning - and determined he must be near the Concord Naval Weapons Station. The Coast Guard also worked with Hopper's cell phone provider to triangulate his signal.

After finding him waving a red flag, the Coast Guard learned that the victim had gotten stranded after an unusual adventure.

Hopper, nicknamed Goat Man for his ability to scale mountainsides, said he started out Wednesday morning on the Sacramento River, where he loaded a $300 inflatable raft with camping supplies, two burritos, a bag of vitamins, a Bible and a mannequin of Gov. Arnold Schwarzenegger.

"This trip was a campaign," Hopper explained. "I wanted to bring more attention to social diseases."

Hopper hoped to make it to the Golden Gate Bridge, but disaster struck when his raft sprang a leak in Suisun Bay, east of the Benicia Bridge. He said he managed to guide the sinking vessel to shore, then figured he'd make camp on the island until he fixed the raft.

"He was lucky to make it to shore," said Lt. j.g. Laura Williams, a Coast Guard spokeswoman. "In those weather conditions, it's cold, the water is very cold, and it can be really dangerous."

Hopper said he tried to scout the island for life, but high winds pushed him around, making walking difficult. He slept the first night in a tent and spent the next morning gathering chunks of Styrofoam to plug his raft's leak. The Contra Costa County shoreline was about a mile away.

"I couldn't fix it the first day so I just figured I'd spend another night, even though I was out of food," Hopper said, referring to his burritos. "Thought I'd go to work and try it again in the morning."

The next night the island was pounded with driving rain and thunderstorms.

"The weather," Hopper said, "was not working with my needs."

By the fourth day, Hopper said, he began to worry that his energy was decreasing too quickly. He had picked mustard flowers, eaten the last of his vitamins and used duct tape to write "SOS" on a red tablecloth that he hung in a tree.

Still, his cell phone remained idle. He hoped a passing boat would scoop him up, making a 911 call unnecessary.

As he saw white clouds billow from refineries in the distance, he thought to fan his own smoky fire, hoping an overhead plane would take notice.

At night, to calm himself, Hopper read his Bible. In the mornings, there was the bugle call to wake him - a sound he assumed was coming from battleships he could see to the west.

"I did all the things I saw on TV," Hopper said. "I did everything I could to ensure my safety."

On Monday morning, Hopper finally used his cell phone - to call a cousin in Northridge.

Shawn Reeves, 51, said in an interview that Hopper didn't ask him to call authorities but described his worsening situation. Reeves got a sinking feeling that his relative was in real trouble.

"I could hear it in his voice," Reeves said. "This was a guy I grew up with: If he said he was hungry and needed help, he really needed it."

Reeves said Hopper once lived in a cave in Nevada for three months, had walked through Death Valley and had made a Northern California forest his home for an entire year. "When we found him," Reeves said, "he was naked and fishing in a stream ... He's been living off the land for at least 20 years."

After scarfing down a burrito he bought at the Martinez Marina on Monday in a bid to regain his strength, Hopper said he was glad his cousin called in the Coast Guard. And, looking back, Hopper said he should have called 911.

"It was," he said, "the right thing to do."