Braided makes more sense. I was wondering how the line held up being submerged, seeing how sinew doesn't like getting wet. Did you oil or rub fat into it at all? I have some retted tulip poplar inner bark. It was strong enough to make a bow string with. It might work for a fishing line, worth a try anyway.
Rob- That certainly would put it to the test. I don't know if I have enough sinew to make a string long enough to allow for a steelie to play it self out. I might be able to just muscle it out of the water while it's still fresh and strong. I used to do it that way when I was a kid, 20# braided line with the drag cranked up. I went through 5 or 6 brands of hooks before I found one that didn't bend straight from the fight.