Scott MacDonald said he was with nine family members on July 3, 2010 after a fireworks display and heading back to his father-in-law's property on the north shore of the lake.
"We started heading up lake toward Fraser Bay, just taking our time. We were just cruising very slowly. It was hard to see. It was a really, really dark night."
MacDonald told B.C. Supreme Court that before he spotted the speedboat, he noticed strange lights on the lake.
"Before we got to the houseboat, we see an odd blue light about 10 or 15 feet up above the water," he said of what turned out to be a blue LED rope light on the houseboat.
"It wasn't until we got right beside the boat that my father-in-law said, 'Oh, that's a houseboat.'
"I was kind of shocked that I came up on him and I didn't see him. There was no light evident on the houseboat and that kind of concerned me. So, I just focused on moving forward."
MacDonald said he passed the houseboat and then noticed the lights of another vessel in the water.
"We saw the lights from a boat doing donuts and zigzagging — driving erratically," he said. "I remember commenting that he was pretty close to shore to be doing that because there's always boats tied up."
MacDonald said he took an extra wide path around the boat to be extra careful.
"I was concerned we'd get crashed into, so I just veered off."
B.C. Supreme Court has heard the speedboat driven by Leon Reinbrecht slammed into the houseboat, killing Ken Brown.
Reinbrecht is charged with one count each of criminal negligence causing death and criminal negligence causing bodily harm. (Kamloops This Week)