I have a question I would like to ask about historiographical methodology, namely how one would go about determining whether a river was navigable in the past and up to what point upstream. However, unless a specific academic methodology existed for this purpose (which I don't think it does), the answer sounds to me as if it would be:
- Extremely dependent on what time period and area we were talking about.
The alternative for this is to ask my question as, e.g., "How far up the Gauja River could a Bremen trader sail in the early 13th century?", but this, for me, is:
- Extremely specific & therefore unlikely to garner many replies;
- Easy to miss if a similar question was to be investigated (e.g., if the next person was interested in the Niemen and not the Gauja);
- For many places, extremely dependent on adequate primary sources to prove that the vessel had been that far upstream which could be data that simply is not in existence (if it ever was).
I am unsure of the tightrope between these two extremes, although it could be that, e.g., "How far upstream could a cog sail?" would be the best version which would then have to be supported by either primary sources, the length/breadth of the cog, and its draft as well. Yet, this would also mean that we could have fifty questions on essentially the same issue (although, of course, it would make more sense to ask "How far upstream the Nile could Thebans sail in the 20th dynasty?" over a specific vessel type in that specific location...).