I believe you are right Murray. Quite apart from scientific exegesis, logic alone tells me that if Rabbi Jehoahin uses a bow to tie his string, despite believing string was not used, while Rabbi Saul says string was used because the string was tied in such a way as to be easily removed (obviously using a bow) then they have contradicted each other.
So we are left not knowing anything – which is beginning to feel more comfortable the further we go.
Mal