Mark sez, "In the original Anaheim Disneyland it may be a Small World after all, but that world's inhabitants are getting bigger and heavier almost by the day, so much so that some of the rides may have to be re-engineered. This has already been scheduled for the Small World ride, which will be closed for almost a year beginning in January for retooling. When the ride finally reopens, the flume will be an inch or so deeper and the boats more buoyant, thus allowing for several hundred more pounds of capacity."
The Small World ride now must accommodate adults who frequently weigh north of 200 pounds, which it often cannot do. Increasingly, overweighted boats get to certain points in the ride and bottom out, becoming stuck in the flume.