How did the Hansa accommodate the transition from sea to river trade along a trade route? Would river travel have been controlled by one group of people, e.g., Guild of the River Oder Merchants? Would the river traders have been moving all through the river's extents, or from one portage to the next (and have someone else pick it up there? Would it make more sense to portage ships or own ships on both sides of the portage area?
I've specified this question to relate to the Hansa League who had numerous cities (Thorn, Magdeburg, Dorpat) upstream from the North and Baltic Seas.
I have been meandering towards such a question for a while now. I'll first refer to the Meta where I asked about how I should do this: you can see my hesitation but also my aim there. This relates, like my accompanying question 'How did toll castles operate?', to the Late Medieval period of the 14th and 15th centuries trade.
Tangent: I started thinking about this while out & about crossing rivers (on bridges), and looking at the main flow channels, etc. My question (especially knowing that settlements, such as towns, manor, villages, would exist upstream at least since the 13th century) was whether these were suitable for river travel / transport of some kind.
My main sources derive from the Osprey series' books relating to North Europe and the Baltic (only because those are the Ospreys I am most familiar with). This is also the area I am most interested in at present -- focussing on the HRE territories bordering the North and Baltic Seas, roughly corresponding to the Hansaetic trading league's territories. Potentially, a difference might exist in these lands compared to the rest of Europe due to Roman power never extending this far; although, I am not convinced that would affect the importance of river travel nearly a millennium later.
The vessels used for river trade seem to have been very specific (and seagoing vessels, like the cogs mentioned in my Meta question, would not have been used). Conversely, the special design of these vessels would also have made them unsuitable for use on the seas.
In Livonia, river boats known as bofskip played a major communications and military transport role, linking the otherwise scattered komtur administrative districts, each of which was governed by an advocatus, or bailiff, based in its main castle. [Nicolle, 'Lake Peipus 1242: The Battle of the Ice']
The Scandinavian countries, most notably Norway and Denmark, continued to use later modifications of the old Viking Age longships right into the 14th century. This style of ship, known as a snäcka [the author means a snipa, which is the proper Swedish term while snäcka applies in Norway and Bohuslän] in Sweden, was an ideal vessel for transporting troops, being able to carry around 25 men plus their equipment, and being extremely seaworthy. It was equipped with oars, which made it less susceptible to being becalmed, and which also enabled such vessels to navigate estuaries, rivers and lakes. This versatility, along with its shallow draught, made the snäcka suitable for both transporting and putting ashore men and equipment during various crusading campaigns. [Lindholm & Nicolle, 'The Scandinavian Baltic Crusaders 1100-1500']
I understand that straightforward downstream transport of goods could have been done by (unmanned) barges, or by floating the goods (such as logs). I don't know if there are examples of this in European sources but this is well-popularised in American films depicting the 19th century.
Riverine ships in Scandinavia and the Baltic are described as shallow-draft, clearly indicating their suitability for traffic in variable depths (but including very shallow areas). Also mentioned are portages due to frequent cataracts, as on the Daugava which is unlikely to unique insofar as rivers go:
As the Daugava nowadays has been radically controlled by dams and hydroelectric schemes it is difficult to appreciate that at the time of the Teutonic Knights the greatest river in Latvia was notorious for the large number of rapids along its 640-mile stretch. Over 100 rapids were identified and known. [Turnbull, 'Crusader Castles of the Teutonic Knights (2)']
Cataracts form natural strangleholds on the river where the boats would have to beach. However, these places would also have strong defensive potential, such as for constructing toll castles or townships (perhaps to sell goods?).
Additional Question #1: Do we have extant records of pricing? How does river travel compare to marine and land travel in cost?
Additional Question #2: North Europe has numerous seasonal rivers which freeze in winter. The Hansa would have been very familiar with these circumstances. What would the river traders have been occupied with during this season (presumably, the sea would also be more hazardous so less goods would have been transported to the mouth of the river to begin their journey upstream)?
Let me know in the comments if either of these additional questions warrants their own topic.