|Well I once held the world record, for catching fish on a cast fly at depth. Specifically, I was targeting yellowtail, on the very deep reefs around Loreto, and out beyond Punta Lobo, on Isla Carmen.|
I was able to hook, and land with a stripped fly, that was 300 feet deep.
I used a full 30 foot lead head, made by inchworming 30 feet of 4-Amp lead fuse wire, into a 45 pound braided Dacron squidding line. Don't use resin core solder.
It required, a Scientific Anglers, System 12 "Great Equalizer" fiberglass rod to cast it, and I used 25 pound, thereabouts Amnesia running line. This was in the good old days of fair dinkum 15# max, SWFROA class tippets. I used pretested Hurricane mono line for tippets. The spool came with a three break test right on each spool.
So the trick was to get upwind of the seamount, where the YTs were hanging out, and strip out a hundred feet or so of Amnesia, and then toss a big Lefty's Deceiver, as far down wind as you could. The deceivers were big and bushy, to move a lot of water. Some of Dan's Whistler patterns also worked really great. They became my favorite yellowtail flies. Green over white RG (red / Grizzly), and green over yellow RG.
Now I also had to shoot a little slack you understand; well excuse me, I meant to say a heck of a lot of shooting slack to get all hundred yards of Amnesia out there.
By the time the boat drifted down to where the fly was, well the line was straight down, and you could feel it pull tight at the bottom (of its descent).
Then begins the fun part. You start stripping, until you have no more than 50 feet on the deck. Then you drop the line while reeling frantically to get some of that 50 feet of Amnesia, back on the reel. So the fly drops again doing this, and comes to rest at a lesser depth. Eventually I would get a grab, and the tussle would be on.
A few times, I got a grab in the first three strips. I discovered early, that you have to do the fifty foot and reel thing, because one time, I had 150 feet of 25# Amnesia on the deck, and I got bit. A monster birds nest went whistling up my Fuji ring guides, and stripped the tip top off the rod. Bang ! gone was my bushy fly, half of my Amnesia, and my thousand grain Earthquake Lead Head.
I reckon, I landed a dozen YTs in the 25 -30 pound range, over a couple of trips to Loreto; maybe it was three trips.
So it is lunatic fringe fishing; hardly cricket; but a genuine fly hand stripped and actually casted for part of the trip down. Yes, deepest grabs, with 335 feet of line, head and leader, and three strips for the grab, so I reckon the fish were at 300 feet down.
I've fished 100 feet down, with Earthquake heads, at San Luis main lake by the tower gizmo near the dam, for stripers.
Yes, just an exercise in "can you do this."
Not for everyone. I have two better rods now. A custom TFO (thank you Rick), S-glass, rod for Los Angeles Class submarines, and also A very nice SAGE rod built from a S-glass blank. (thanks to Jerry Siem, at SAGE.
So you can get down deep and fast , but any plastic coating on the head, slows it down a bunch.