This is intended to be the start of a series on the texture of the ACKS standard setting, the Borderlands of the Auran Empire. Understanding the texture of a dungeon is generally simple: a Melan diagram, maybe color-coded by faction, and you are set. Hexmaps, lacking walls to confine player movement, are daunting at first. But a good hexmap provides paths of likely travel, and the Borderlands is a good hexmap. Let’s see how it works
River Depth and Transport
We are going to talk about trade patterns shortly, but first, we need to establish where those trade patterns happen. The roads of Borderlands are obvious, standard Auran paved roads, but what about the rivers? Are they navigable? How deep are they, what boats will float along them?
A spreadsheet (available on request) shows that cargo passage per stone-mile on a large barge costs 114% of on huge barge, while a small barge is marked up to 147% a huge barge. Meanwhile, a small sailing ship costs 55% of passage on a huge barge, a large sailing ship costs 42%, and a huge sailing ship costs 80%. (these calculations based on an investment ratio per month of 33 and hiring labor at each end for loading/unloading) This tells us that huge sailing ships are impractical ego pieces, and that huge barges are generally inferior to large sailing ships (large sailing ship and huge barges have the same draft). These results are aesthetically pleasing and realistic.
Thus, we can conclude that there are 5 levels of river navigability that we are concerned about: deep enough for large sailing vessels (10 foot draft), deep enough for small sailing ships (5 feet), deep enough for large barges (3 feet), deep enough for small barges (2 feet), and not navigable (except by rowboats and canoes). Note that these all actually require a channel of depth 2 feet deeper than their draft to avoid the occasional sandbar, but I will stick to referring to rivers by the draft of boats they can handle instead of the depth of the channel.
Up The Mirmen River
One issue in assessing the depth of the rivers in the Borderlands is that our best sources were written in the before-times, when boats had wildly different drafts, costs, and depths. As such, the listed ships in AX3 aren’t very helpful. However, we do know that the Mirmen is as much as 50 feet deep in places, so it is fairly reasonable to assume that ships of any draft can make it to Cyfaraun. It seems reasonable that Arganos (off map) finds much of its traffic sailing right by. However, at Cyfaraun, we hit our first real limit: the bridges have five arches to cover 125’. Given that a sailing ship has a beam of 24’ or 25’ feet (small and large), we can feel confident that sailing ships will stop here. Since the ability to sail upriver without transshiping onto a barge is valuable, it is likely that this is also where the river gets shallow enough that at least large sailing ships bottom out, and only ships with 5’ draft or less can go further. A sharp change in depth here is justified by the layer of volcanic tuff that covers much of Old Cyfaraun. Notably, 6 and 8 rower galleys can proceed no further, while 2 and 5 rower galleys can, barely.
Turos Quell is the next settlement on the map upstream, and it is built on an eyot where the river shallows and widens. It is connected by bridges to the west and to the southeast. It also connects by a flooded cutoff to Lake Laman, which in turn drains slightly back into the Mirmen river closer to Cyfaraun. The Viamir marshes are to the southeast. Notably, Turos Aster is the absentee landlord of the lands to the west of Lake Laman, and the Viamir marshes almost exclusively border either Laman or the Palatinate of Sidanos, which does not include Turos Quell, yet Quell is tasking with patrolling this area with flat-bottomed skiffs. This implies significant dilution of responsibility, but for our current purposes, it is sufficient to note that the river shallows here, likely to the point where ships no deeper than 3’ draft can continue upriver. This may seem pointless, since even the small sailing ships were stopped by the bridges at Cyfaraun, but the 4 and 5 rower galleys must stop here. Since the Auran empire generally does not build its lighter ships as cataphracts, this means the ships get much weaker even as the danger increases (Turos Quell is where civilization shades into the borderlands). In all likelihood, there are some purpose-built cataphract 3-rowers for this stretch of river.
The town of Sidanos, according to the AXIOMS article on the Patreon, has a substantial waterfront presence. This sort of town is often seen at the head of navigation, and matches a pattern of one town at the river mouth (Arganos) one at the point where the river shallows (Cyfaraun), and one at the uppermost limit of navigation. It is likely that only vessels with drafts of 2 feet or less can head upriver of Sidanos. This means only small barges and sailing boats, no purpose-built warships.
Turos Telle sits on an island in the Mirmen. Its primary role is to anchor the southwestern end of the Unbroken Line, but such island usually form where the river slows down and deepens, so it is reasonable that it is also the uppermost limit of 2’ draft vessels. Turos Erin is supplied from here (its territory actually cuts above Turos Telle), and perhaps Turos Drav. Turos Luin is supplied from Sidanos by the eastern road (as can be seen from its territory stretching back along the road), and Drav is closer to Luin than Erin. Guarding these ships is a challenge, and usually only done for military supplies. Going further can be done on rowboats and canoes.
We actually aren’t done, though. In elder days, the Redoubt on the Earthway carried ore down from Azen Kairn to market. This was likely done using rafts. While the listed raft is less crew efficient and slower than even a small barge, the one-way nature of this trade means it can be done using single-use rafts, which would use the Crude Construction rules and cost around 1/5th as much. The rafts would be chopped up for firewood at the end of the route. Because the route is entirely downriver, the crew could be neglected in favor of simply allowing the current to pull it downriver. Much of The Adventures of Huckleberry Finn takes place on such a raft. Beyond the Redoubt, though, not even such 1’ draft vessels can continue. Canoes can go a little further, but, since the mountains are right there, not far.
In sum, canoes from the mountains to the Redoubt, rafts to Telle, small barges to Sidanos, large barges and non-battle-line galleys to Quell, reasonably-sized galleys and a few stranded small sailing ships to Cyfaraun, anything goes from there.
Up the Krysivor River
We need to get one thing out of the way: the Legate of Turos Aure is a felon. Per Capital of the Borderlands, it is a major import location for spices and ivory from Ulrukan. However, why would long-duration voyage vessels stop at a tiny Class V market instead of might Class III (or even II?) Arganos. Why transship their goods through a mode change (by hand, with lossage from sticky-palmed dockworkers) across dangerous outlands and around 100 miles of road, just to get to a city (Cyfaraun) that they could likely sail to directly? Overland travel is expensive! As I said, the easy explanation, supported by the entry in Capital, is that “Legate Retunus Natherian is a greedy and grasping man”, likely tariffing the luxury goods as common goods for 5% instead of 20%, then pocketing 10% in bribes. Given the advantages of Large sailing ships, especially for long voyages, it is likely that there is a channel 10’ deep into Turos Aure. However, as we will see, the Krysivor shallows rapidly, and beyond Aure it is likely only safe for draft 5’ vessels, if that.
Turos Veren is at a place where the river is not fordable in any season, so I put it at still around 5’.
Turos Gundan has a small ford, so I’d say the river narrows to unsafe for 3’, safe for 2’ (remember, this means 4-5 feet deep). Only small barges can reliably go further.
However, by Turos Augil, the river is no longer fordable, and draftier ships could be built here… and be trapped. This is unlikely. The river is too small, the border too contested.
We have nothing to base our assessment of the fordability of Zelictium on, likewise, Turos Morn is a cipher.
At Turos Spen, however, we learn that the confluence of the Blood River and the Krysivor is shallow and at times fordable. Small barges can likely get past this but likely do so rarely. Little is south of here that couldn’t be moved affordably on wagons, safe on the west bank of the river. The Blood, by the way, is named for its sediment, and is probably a complete mess of sandbars. Canoes, rafts, and rowboats only. It is into the wild, though, so who cares? (adventurers)
Turos Aster sits on another ford, staring across at an out-fort occupied by bugbears. This is probably the beginning of regular fords and the end of reliable boating. Turos Tem is quite detailed in Sinister Stone, and has no waterfront at all. It does have a ford, though. Turos Luin is at a deep point, but few boats are built here. Turos Drav sits at a useable ford. The Kyrsivor runs through a few more grassland hexes, likely too fast to safely ford but still shallow, then heads up into the Madoan Hills.
In sum, canoes to Drav, rowboats to Spen, small barges to Gundan, large barges and non-heavy military galleys to Aure, which can handle big ships (thanks to dredging).
Next, we discuss the trade patterns of the borderlands.