There are several ways of using flys when going after a toothed fish. The most popular involve bite leaders and shock tips.
(1) Short wire leader, piano wire and wires of that ilk. 6 to 10 inches long for most applications.
(2) Short heavy mono-filament 35 to 50 pounds as needed, for the fish to chew on and not cut through.
(3) using a tube fly w/wire or shock tip.
The fly is tied on a metal of plastic tube (straw) and slides over a wire leader down to the hook.
When we were young these were called Quill Flys, because a goose or turkey quill was used with the van (the feather part of the feather) removed, then trimmed (cut) to the desired length, slipped over a dowel and a fly was tied on the quill. This method allows you to tie large flys and use short shanked hooks. When a fish strikes and you set the hook. The fly will slide up the leader leaving a short shanked hook in the fish, which is harder for the fish to throw than a long shanked hook because the fish can't get much leverage.
(4) Came upon this one a couple of weeks back.
The tag end of a loop knot fly line connector with a slider on it is tied on the hook first, then the fly is tied over it. The hook point is cut of at the top of the bend, leaving the fly with no hook and a loop knot w/slider ticking out about 3 inches in front of the hook eye. When fishing with this fly, use a bare hook with short wire leader. Put hook through the loop of the fly's knot leader and push the slider up against the hook. This puts the artificial bait about 4 to 6 inches behind the hook and prevents the fly fisher from gut hooking pike, and other toothed fish.
Now, That I've explained all that. I know of several cases where blind dumb luck and skill did the trick.
For Example: On my second day at work in the fly shop, a gentleman came in with the shakes and eyes the size of the old silver dollar. I asked if he were OK, and was told yes. I mentioned he looked a little shaken and offered to get him a chair.
"No thanks" he replied. I then inquired if he could tell me what had happened, thinking that he was about to describe a traffic accident.
"I just caught a 4 foot hammer head shark".
"On the backside of Tybee."
'Neat, what did you catch it with?'
"A big streamer, on my 5 wt"
'That is amazing! What did you use for a bite leader?'
'I'm very impressed!, How long did it take to land it?'
" Just over 2 hours."
'How may I be of service?'
" Sell me a 9 weight!"
And that is just what I did: Rod, Reel, Backing, line, leader and bite leaders. I didn't even point out the difference between a Bonnethead and a Hammerhead. When you are looking at the business end of a fish with big sharp teeth and eyes sticking out each side of its head, on the end of your line. The difference is unimportant.
I've never fly fished or know much about it but I honestly expected Jessica to jump in here with a smart alec comment about catching fish with your teeth LoL
Seriously though, I need to be wealthy and retired because there is soooooooooooooooooooooooo many things that I at least want to try in the outdoor world. More than anything... there just aren't enough hours in the day nor days in the year and I can certainly see myself doing a lot more fishing of any type!!
LOL.........I must be slipping.....No..just been real busy this week. Real Estate is booming..The high rollers are buying again......$$$$$$