Todd Kerr, who was 39 at the time of the Aug. 2, 2008 accident on Shuswap Lake, was charged with dangerous operation of a vessel causing death and dangerous operation of a vessel causing bodily harm.
But B.C. Supreme Court Justice Robert Powers ruled in a decision released Thursday that while Kerr's actions were negligent, the Crown had not proven criminal liability.
"It is important not to simply leap from the consequences of the actions and the fact that the driving was clearly negligent to criminal liability," said Powers.
The judge noted Kerr's evidence was not "seriously challenged in court," and one of the women injured in the accident said Kerr was "generally conscientious" about the boat's operation.
As a result, Powers said he had a reasonable doubt.
The court heard the nine-metre speed boat was travelling at about 48 kilometres an hour in the dark, and nobody onboard saw Copper Island, an uninhabited island in the lake with steep, rocky sides, until the collision.
The court heard the boat struck the island about 150 to 300 metres west of a flashing-green navigation light.
According to court documents, mariners travelling up stream should keep flashing green lights on their port side, which is on the left.
The boat then travelled about 4.7 metres up the shore and struck a tree, before sliding back into the water.
Pattie Lynn McKenna, one of two young women who'd been picked up at a marina before the crash, died as a result of the injuries she sustained.
Several others in the boat were injured.
Not only did Kerr not see the island — visibility was limited to about 6 metres — he did not understand the meaning of flashing navigational lights, "except that they marked a hazard of some sort and should be avoided," said Powers.
He also said Kerr was travelling "at a higher speed than a reasonable person would have done in the circumstances.
"His failure to appreciate the significance of the lights that he could see and his decision to operate at the speed he did was negligent."
--by Keven Drews in Vancouver