Having read through the thread thank you for all your imput
It also occurs to me that Malcolm's single may have slid out of the fish's mouth because it was fishing on its side - Hugh Falkus was insistent that one should check that a fly swam properly before starting to fish. I think the increased weight of 'keel' from the two points of a double increases the likelihood of a fly fishing right way up, which is important not only for secure hooking but also proper presentation (unless, like the Willie Gunn, your fly is tied 'all round' without a defined top wing).
The fly as far as I am aware was fishing up right, it was an Ali shrimp and it looked good before I sent it forth.
Willie Gunns tied on a tube with a single hook, How would you ever know wether the hook was up down or side ways, more worries. The gillie says I worry about the science of it all I should just choose a fly and fish it, changing flies just wastes nylon
As usual you talk sense, but do you always use tubes? do you ever use standard dressed flies? I could see why you don't.
I will have to try these Loop Doubles.
Offset single hooks may improve hooking very slightly in the situation you describe. I used to fish an offset Gamakatsu single hook. I no longer bother with offset single hooks and notice no drop-off in hooking-to-landing ratios
I was thinking about bending an off set into all my singles but if you find no difference I will save myself the effort.
Now that three days have passed and I have relaxed maybe it was just on of those days. I hate loosing fish I can remember fish lost as a boy over 30 years ago much better than the ones I caught. Saturday was a pig of a day the wind was 25-30 MPH downstream,if you couldn't Double Spey it was too dangerous to fish.