Been around boats all my life. Know that CO is deadly but didn't know it was in this envronment. Sad and scary.
https://www.hccommunityjournal.com/article_2c3903cc-f1fb-11ea-9314-0f8c02b6e971.html?utm_medium=social&utm_source=facebook&utm_campaign=user-share&fbclid=IwAR2MjTwGxe2fTFe6Gyb3Q9IWZ5YuOsaKhQCY4_xQ30oPlQkhPVsztGLVk54
Truly a sad story.
Back in the early 70s my friend owned a pickle fork flat bottom boat we used to ski on the Sac river.
The thing would swamp on a small swell, needed to keep moving to avoid sinking. Really, it was a racer, not a pleasure craft.
One day he said he was selling it, said CO almost killed him. Because it sat so low on the water, CO had nowhere to go but to pool around the boat.
He had a cove he always pulled into so as to avoid passing crafts waves that would most assuredly sink it. It was this dead cove where he discovered the exhaust issue that damn near killed him had the engine not stalled by itself.
Said he woke up in the night with a splitting headache. He loved that boat, but life took precedent.