RUSKIN — On a clear, cool morning in February, two small boats on a collision course sliced through the calm waters of the Little Manatee River.Arthur D. Showley sat in the back of a 16-foot Sea Nymph, steering the aluminum boat west using the tiller on an outboard engine. Meanwhile, Steven Boomer piloted a 19-foot fiberglass Sundance from the center console, heading east.The two captains made futile efforts to change course before colliding in a violent crash that killed Showley, 75, and injured other passengers in the boats.The new details of the Feb. 23 incident are included in a final report obtained by the Tampa Bay Times through a public records request. Boomer, 59, of Ruskin was later cited for violating navigational rule 14, which requires boats approaching from the opposite direction to steer to their respective starboard, or right side, to avoid a collision, according to the report. Had he survived, Showley would have been cited for the same violation. The crash happened about 8:20 a.m. near the mouth of the river, east of Shell Point Marina. The two captains tried to avoid a collision, "making several alterations to course upon seeing each other in the head-on situation," FWC Investigator William Freemon wrote in the report.The Sundance ramped over the starboard side of Showley’s boat, traveled along the craft’s gunwale and struck the two other men on board, David Sheppard and Edwin White. White was knocked into the water. The bow of Boomer’s boat then hit Showley on the right side of his neck, throwing him into the river, too.Investigators estimated the boats were traveling between 21 and 40 mph at the time of the crash.Boomer jumped in to help Showley, who was face up in the water, unresponsive. The report says he suffered a spinal cord injury and cuts to his aorta and carotid artery, but the cause of death is listed as drowning.Sheppard, 81, of Nova Scotia was treated at the hospital for contusions on his arm and shoulder. White, 65, was also treated at the hospital for contusions and cuts on his arm and chest. Boomer and his passenger, 61-year-old Thomas Nicol, escaped injury. Boomer declined to comment when reached by phone.Showley was a retired farmer from Kewanna, Ind., a town of about 600 people, according to an obituary. He spent about half the year in the Tampa Bay area and the rest in Indiana.A former county commissioner in Fulton County, Ind., Showley had been married to his wife, Dorothy, for 52 years at the time of his death. The couple had three children and four grandchildren. "His Indiana family, friends, and strangers alike enjoyed the produce from his garden and fruit trees, while his Florida neighbors delighted in eating the abundant quantities of fish he pulled from Tampa Bay," the obituary said. "To the Red Cross he donated his blood regularly, to St. Anne’s Food Pantry in Ruskin he donated his time weekly, and to the Habitat for Humanity of Fulton County he donated his skill faithfully."Contact Tony Marrero at [email protected] or (813) 226-3374. Follow @tmarrerotimes.