Flyfishing does work very well in the seaway. I dabbled with it for a couple of months in 2013 and caught a few fish with it, but nothing big. It takes quite a bit of practice to get good at it, particularly getting the fly in the right zone. Flyfishing in the seaway is less casting and more like deep fly. Letting your line sink to the bottom and stripping it back. The most common flyline used is a striper IV and they even add pea sized sinkers to the end to really get the fly down fast. Best fly is a white bucktail fly with a red belly and a bit of flash.
There are two older guys who only flyfish and they do catch some nice fish, Vince and Andrew. Andrew(guy with the beard and straw hat)is the top Flyfisherman and catches more fish in the seaway than anyone I know. He does fish hard though. If you can get Andrew to talk to you then you’ll learn alot about flyfishing the seaway.