Someone educate me on fly hooks, please....

My wife always tells me that I observe too much, but, it is just something I do and now I have observed something that I need someone "in the know" to explain and educate me on fly tying hooks.

Fly tying hooks can be TDE (turn downed eye), TUE (turn up eye) or straight shank. Most of the straight shank eye hooks are streamer hooks of some sort which I understand the purpose, but, when I look at the rest of the hooks they offer, I find that 95% or more of their hooks are TDE hooks and very few TUE hooks. It does not seem to matter if the hook is for dry flies or wet flies. Most of them are TDE. There had to be a reason for making TUE hooks and I would like to know what that was. As I look at different vendor's hooks, I notice they offer maybe 15 to 19 different hooks and out of that number there may only be 4 or 5 that have the TUE. I did notice that when you look at saltwater hooks, there are more either straight eye or TUE hooks then TDE hooks.

Just curious and nothing more and I feel someone here is in the "know" and can educate me on this.

Thanks in advance....

Cannot quote you a source, but I believe there was a time when the up eye was favored because it was easier to snell. The straight and down eye were just later evolutions as materials, techniques, and preferences changed. In addition to the ones you mentioned, there are also jig eyes of various forms, loop eyes, flat-eyes, and 'no eye' hooks. Curious that what you say about saltwater hooks (conventional and fly), because almost all the ones that I'm familiar with are straight or down eye, except for the 'octopus' style hooks perhaps.

There are some that will argue that the different eyes have different hooking abilities, which explains why various styles have developed over the years. Manufacturers have tried different styles over the years to entice fisherman to buy different styles of hooks, and market differentiation resulted in the plethora of choices we enjoy today. If you are looking for a 'rational' reason for why there are all the hook styles there are, other than marketing, I think you are going to be disappointed.

Warren,

As are most things in fly fishing (I'm sure you know that), it depends on who you ask. I'll get to that shortly. Different types of eyes on fly tying hooks: TDE, TUE, Straight Eye, Looped TUE, Looped TDE, and No eyes(for snelled flies). I may have even missed 1.
WHY : Some writers consider the angle of the pull of the point important and the direction of the eye a key to that angle. Maybe yes, maybe no. Some prefer the 'look' of a fly tied on one or the other. The 'looped' eye does not have anything rough on which to cut the tippet so it's more secure but added wire results in a heavier hook. These are used mostly for wets/nymphs and streamers although in xfine wire can be used for low water salmon flies. The eyeless hook is 'classical'. The manufacturers, at least some of them, offer choices. Then we select what we do based on how we've been influenced and what's available.
I've never measured the shank length of say a Mustad 94840 TDE and a 94842 TUE in the same size but I 'think' or I've heard that the TDE offers a tad bit more tying length. Not sure if that's true. On the tiny stuff, 24 and smaller, I think that a lot of tyers prefer the staright eye.
Have I cleared this up? LOL.

Allan

As Allan said, there are lot's of reasons for the different configurations of eyes on hooks. (I think he left out tapered eye.)

I think that much of the preference for TDE is the ease with which a right handed tyer can trim, say, the wings on a winged wet. TDE, he just lays the the scissors more or less along the eye and snips. It's a lot harder to trim something on top of the hook with a TUE. Also, some people believe that a TUE has a tendency to pull the hook out of a fish's mouth, a TDE in. (I don't think this has been proven one way or the other.)

On smaller hooks, TUE or straight (aka "ring") eyes don't get in the way of hooking a fish.

The Turle knot, now seldom used, only works on TDE or TUE eyes, not on ring loops. Even if the Turle knot isn't widely used anymore, it was at one time, and tradition still counts in fly fishing.

Now, let's talk about bends ... is Limerick better than Sproat?