Let me preface my reply,that i spent the first 25yrs of fishing on erie casting with weight forward or harnesses west of bass islands in boats my father owned.I bought some trolling rods and inline boards because was interested in fishing another way.Back then,there was no internet or fishing sites to learn about trolling techniques.Unfortunately,my dad never let me try out the trolling gear except for a couple hours a season.A buddy of mine bought a lakehouse on Johnson island about 15yrs ago,so took my trolling gear over to his place and tried trolling off his boat.Needless to say,we didnt really know what we were doing at first.Luckily i had a new patient show up around then that was a big troller.He pointed us in the right direction at the beginning.From there,experience and reading fishing websites have taught us a great deal.
Now,why troll instead of cast.When it comes to gear,all you need is a few spinning rods and harnesses to cast.To troll,it's probably a couple thousand bucks to get gear to troll.Big difference there.I don't own a boat,so i rely on my buddies to take me with them.Now, i help them set up their boats to troll and be able to catch fish without me.I feel it's easier to catch fish trolling when first starting out than it is to catch casting as long as you have the proper gear.And,if my buddies wanted to cast instead of troll,i would do whatever they want.But the guys i fish with want to troll and expect a good cooler of fish for the time and expense they put in to fish that day.
Now,if i had my own boat,and had two other good casters with me,we would be able to catch a limit,or close to it at certain times of the year.During the prime walleye casting months of late May thru July,you could do very well casting with harnesses.Especially if there are alot of younger legal fish that you can find.But there are times where even good casters can find it difficult to catch fish.When that happens,the trollers will usually outfish the casters.Those conditions are after a prolong blow and low pressure system that affect water clarity.Casters are also limited by the amount of wind.Not enough or too much wind and casters will struggle.I have also found it much more difficult to catch casting if the water was deeper than 30ft.So when the fish move east into deeper water, as the water warms,the trollers have a huge advantage.To top it off,the trollers will almost always catch bigger fish than the casters.
Have seen the fishing evolve from those huge packs of casters in the 80s to most of the boats trolling now.I know there are a few charters that still exclusively cast and they do quite well and have alot of repeat customers that only want to cast.Ideally,would be best to be set up to both cast or troll.Based on the success and conditions.Got a trip set up in June to do just that.Buddy wants to start out casting.But bringing the trolling gear just in case need to switch over to fill the cooler.