Sorry the 20' of line out is meant to say trolling with 20' of line out, however I read the book wrong and it was at 40' where it exceeded casting depth of 10'....I guess what Im not understanding is we move the bait with the reel from a stationary boat, trolling, the boat is moving but not the reel... is the difference in depth due to boat speed or line out? I was always of the understanding that a bait will only hit a certain depth no matter of the speed of retrieve, sorry for the confusing post Im not really sure how to word this question? So in a nutshell their saying that trolling the same lure with 40' of line out acheives a greater depth with the same bait than casting the bait 100'