You can use a fly and bubble. You put on a casting bubble and I use a small lb flourocarbon leader to attach the fly. You can also attach a second fly to the first one. I usually pull it in a couple feet pause for a bit and reel in the slack and repeat to the shore. WIll
PoPoJiJo is right on. A casting bubble, the type you can add water to, and have the line slide through is the ticket. Slide the line through the bubble, attach a swivel for a stop, then a 2-4 ft leader, and a fly. Nymph patterns size 16-12, grays, blacks, peacock and browns are great starts for trout.
Flilng it out, give a quick pull to straighten things out and then a slow retrieve and you're in business. I did a lot of fishing that way before I figured out how to use a fly rod and still recommend it as a way to introduce people to fishing with flies and lures.