The public right of navigation is so ancient that no-one can identify a time when it didn't exist. Much of the evidence for it is also old and has sat on dusty library shelves for centuries. But now, thanks to the internet and programmes digitising old documents and texts, this evidence is being made available and recognised again.
One such document is "Instructions for Jury-Men on the Commission of Sewers" a 61 page publication from 1664 which educated and briefed Jury-Men on the law and their duties in applying the law. It contains some very clear references to the nature of navigation which was protected by the Commissions of Sewers. Such as
and"Now the Commission of Sewers, in a matter of such great import as this of Navigation, is very exact and careful
1. First in respect of all Navigation,
Whether it be with Vessels of the greatest bulk, as ships
Or Vessels of the smallest kind, as Boats
Or with Vessels of a middle nature, as Ballingers; ..........
2. Secondly, In this Point of Navigation the Commission is very exact in respect of all Waters that be in any manner Navigable; ..."
There is no indication in these "Instructions" that public navigation rights were confined to tidal waters or to a few "Great Rivers" and yet if such limitation did apply, they would clearly be mentioned. Every few weeks we find more evidence of this nature and it all supports the notion that all rivers (and streams of flowing water) were considered navigable subject only to the physical constrains of the rivers and the nature of the craft using them."..... and though this, as all other streams of this nature, be Navigable but with boats, that is with Vessels of the smallest size only, yet as I formerly told you, such Navigation is to be preserved."