I was trolling at the slowest speed on my 60 hp merc 4 stroke, which I don't have an exact mph but it's slow yet fast enough to get the crankbait deep enough. Last year I found an area by the dam that was stacked with walleyes, mostly 14 inchers, but some keepers too. I mean they were thick suspended in 30 feet probably half way down. They stayed there for a month or so before disapearing. My wife and I sometimes caught them on every pass. Lots of shorts but steady action with the possibility of big crappie to either side of them. Lots of fun. Watch the guys trolling, where they are. They are there for a reason usually. I've learned more by watching others than on my own. I don't get too technical, lol, more so a creature of habit along with trial and error. There are lots of areas like that around the lake that produce like that when the trolling bite is on. It's a good way to relax, eat cheese and summer sausage, maybe one cold one, and take in the sights.