If you look at the logs, themselves, then you'll see that they have wheels on the bottom of the boat (and I've never been a fan of partially empty troughs where you're just rolling on the bottom) and along the sides of the boat, but still on the bottom, to keep you floating along in the trough. There was a case like this at Six Flags Over Georgia, years back, that really hurt someone and resulted in a lawsuit. You want to keep the trough full, though, as you can have a nasty accident if a log is coming down the drop and there's no water there to slow it down and float it at the end of the aforementioned track. Everyone else just floats forward until they bump into the log in front of them. Other than that, as mentioned before, if you need to emergency stop then you just stop the lift hill and stop any action in the loading/unloading area. They push those up enough to where it either catches the boat or stops it and you load/unload. They have the rubber conveyor belts there that lift you out of the water at Splash Mountain and provide a stable surface for loading and unloading whereas traditional log flumes would have the underneath-brake which is a set of wood/metal planks with rubber padding. I think Splash Mountain uses gates, if I remember. There are brakes in the station and sometimes they use gates. There may be some jets in flumes like Splash Mountain to keep you going. At that point, traditional log flumes will be gravity based until the next lift hill or station. It keeps you straight and safe in the process. This fills up the splash zone where you touchdown which, again, is mostly done with the wheel and tracks up to the very end of the splash. If you look, there's typically a basin underneath the drop hill where a lot of water is being pumped in (huge pipe and pump). You're going down the hill on the wheels on the bottom of your boat and tracks just to the side instead of down some water plume. The lift hill is "dry" and there's a pipe that goes to the top to have water cascade down the drop side. Most of the ones I've seen push up from the bottom. Now every time my kids and I go on the ride, we hold our breath when we get to the part where we were stuck, hoping we make it through.
LOG FLUME RIDE ACCIDENT FREE
We all got free paper fast passes to use on any ride for our inconvenience. It was kind of a scary experience when it was happening, but was interesting to see the ride with the lights on, and to see the back of the park. There were current and old floats back there, and a large shelf with spare parts for some of the rides. We walked down about 2 or 3 flights of metal stairs behind the ride, and ended up in the maintenance/back stage area behind the ride. We stepped out of the log, and had to wait along side the wall until all of the riders in our "area" were out of their logs, and then they walked us about 30 feet to a door that opened to the outside. After about 10 minutes (which seemed like 30) about 5 CMs appeared and had to unlock the restraining bar in our log with a large tool. We were about three logs from going down one of the smaller drops. An announcement informed us that the ride was having technical problems, and we would all be evacuated, and to remain in our seat until a CM came to escort us out.
We sat there for about 2 minutes, thinking we would start back up, but then the music stopped and all of the lights came on. In May 2015 we were on Splash Mountain and the ride stopped.