We used to float down the skook in inner-tubes and rubber rafts. Speaking of sweepers and log jams, my mom and brother nearly drowned when their raft found a fallen tree where the skook spills into the chehalis. A passing boater (on the chehalis!) luckily saw them and pulled them out (my mom was actually stuck UNDER the tree).

Only boat launch I've seen near the skook is the one just downstream from the skook mouth on the chehalis. Is is possible that these guys came from that far down? Or is your spot too far upstream?