When all works as designed the rope-chain splice goes in smoothly. There is a stripper that's a spring-load arm that holds the rope/chain against the back side of the capstan until it is directed down to the locker. Sometimes the rope doesn't flow smoothly for example if it is too stiff and the top of the pile is near the top of the locker it may back up and cause a jam. Usually that can easily be cleared by reversing a foot or two then pull from below while trying again. Sometimes if there's a jam the stripper arm can get under the rope then you need to pry it up with a screwdriver or other blade while pulling from below to get the line back against the capstan with the stripper outside it again. You get the idea... that's why people like to be "there" as it comes up to make sure it all goes well and stop the motor quickly before a jam gets difficult to clear. Mine usually goes well, even at the splice, but sometimes... not.

All-chain doesn't have these issues, unless the pile builds too high. Some people need to knock down the pile if dealing with a lot of length.