Yes, that is what the literature says, but I only had to look once at the difference between my low water fly tied with a loop and the same fly tethered with a turle knot to realize that that I was far more likely to get chances to prove or disprove the value of the direct pull theory! In other words - Iknew that I'd hook more fish on the lively quivering loop-rigged fly than on the admittedly secure and direct-pulling - but dead looking turle knotted one. And as we all know - we fish flies we have confidence in much more effectively than those we don't.
When I get home (I'm still at work - though the day is over) I will post a sketch of the knot I use.
Malcolm, I use a a knot that has become known as the Trilene Knot. It is basically an unimproved clinch knot except you form an open loop through the eye of the hook and when you pass the tag end back through it passes through this as well. When I get home I'll attempt a sketch of this as well.
Tight lines - tyler.
Still Living Large!