Arthur,
Whats a cone or wedge anchor? Ive done quite a lot of sailing and regurlarly use lots of different joining techniques and Ive never heard of them. Wouldnt whipping or splicing be simpler, cheaper and lighter? I realise sailing isnt going to vibrate knots as much as in a robot but wouldnt these methods be just as suitable?
I dont know what the coefficient of friction is for fishing line but thats also very low and quite stretchy and the knots never come undone. Incidently the dynema lines used in kite flying are normally joined using knots very similar to fishing knots e.g. tucked blood knot.
Ive never load tested any of these techniques though and I assume youve looked into them, but I just wondered why you considered they werent suitable?
cheers
Mark