Someone reported that sims can't fish on a houseboat with a basement. They also can't fish if there is a hot tub on the deck. Once I removed the hot tub, my sim was able to fish.
Another bug I'm experiencing is stacking straight and spiral stairs on a houseboat that is more than 2 stories tall. With a stacked straight staircase my sim walks to the top of the stairs and comes right back down. With spiral stairs sims can go up, but go into route failure when they try to descend.
I'm playing a vanilla game and have all EPs and SPs.