CASCADE, Idaho - The pilot of a motor boat that struck a set of rocks on Payette Lake, leading to the deaths of two people on board, may have confused signals designed to warn boaters of water hazards with those indicating safe passage, according to crash investigators.

Ronald Stevens, 54, of Boise, was arraigned Monday in 4th District Court on two felony counts of involuntary manslaughter stemming from the Aug. 13 crash. He was also charged with one count of gross and negligent operation of a watercraft.

Stevens was at the helm of a 23-foot ski boat carrying eight adults and four children when the craft struck a bank of rocks near Cougar Island, capsized and sank shortly after 10:30 p.m.

"He is extremely distraught about this whole tragic incident," Stevens' attorney, Mark Manweiler, said in court Monday.

Although Stevens told authorities he is an experienced boater, one investigator said the tragedy could have been avoided with a basic boater safety course.

Sgt. Jason Speer, of the Valley County Marine Patrol, said Stevens apparently confused danger beacons, identified by white lights, with channel beacons, illuminated by red and green lights and designed to indicate safe passage, the Idaho Statesman reported.

But police reports also show other factors may have been involved in the crash.

Investigators say Stevens acknowledged drinking before taking the boat out, and police reports indicate officers smelled alcohol on Stevens' breath afterward.

Police found a cooler filled with beer floating in the water and two bottles of wine at the bottom of the lake underneath the crash.

Police drew Stevens' blood for toxicology tests, but results won't be available for three to four weeks.

Stevens' girlfriend, Linda Catlin, 61, and her son, Shane Catlin, 41, died in the lake. Valley County Coroner Marvin Heikkila said Shane drowned. His mother, who didn't know how to swim, according to family members, died of hypothermia after possibly treading water in the lake for hours.

A 1-year-old girl, Madison Catlin, was treated at St. Luke's Boise Medical Center and released from the hospital over the weekend.

A police affidavit states that nobody on board the boat was wearing a life jacket, including the four children, ages ranging from 1 to 13, even though preservers were on board, some still wrapped in plastic.

Police documents also state that two people on board say that Stevens was facing the rear of the boat, talking with others, at the time of the collision.

Stevens' bail was set at $10,000. A pretrial hearing is scheduled for Oct. 6.