I have put some thought into this because Coho seem to be good for off the beach with only a few reports of Chinook. The only way I figured a fly rod could get down 30 to 60 feet, one would have to troll (I know that is a bad word) say an 1100 grain Big Boy, or 30 feet of T-14 on #35 slickshooter, really slow. If a fly had too much of wobble, you would need a swivel in the leader. I think a large squid imitation of 6 to 8 inches where the tentacles really wiggled around would be better than a fly that twisted your line up. I'm just guessing here. I don't really know and wonder if Les Johnson has tried this. I saw Tres Combs at the sportsman show a year ago and he was really into fly fishing for Salmon off Vancouver Island. He might have an idea too.
Spey casters do it with longer rods