New Features in Under the Southern Cross Part II

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Part I in this series can be found here.

Last time, we looked at how Under the Southern Cross (USC) deals with shoals and sandbars in the various river battles included among the almost two-dozen scenarios of the game. In this installment, we’ll see how river and tidal currents are modeled and how the rules for gunboats have been refined, and in so doing, try to give interested gamers an insight into the design process.


As many of the battles in USC are set in rivers, there had to be a way to represent the effect of the river current on the ships engaged. As I initially approached this task, I was convinced this would be one of the easier new rules to implement. After all, river currents had been a part of other naval games—Yaquinto’s Ironclads comes to mind—and it should surely be fairly straightforward to simply port those rules over to our game and be done with it.

For those not familiar, Ironclads used a rule where ships in the river current were displaced one hex in the direction of the current flow, so that a boat working up stream would make a sort of “three steps forward, one step back” progress. That seemed like a tried and true way to handle currents in USC, so the initial version of our game did just that. Current strength was modeled by the frequency in which ships had to displace: the stronger the current, the more often the one hex displacement took place. However, as we started to test some scenarios, the simple displacement drift caused more problems than it solved. It also created the not entirely realistic effect of “bending” a ship’s course:

Here we see the Spanish schooner Cisne (“Swan”) working upstream at the Battle of San Nicolas (March 2, 1811). Certainly sailing on a broad reach, even in light winds, will help, but the original current rules meant that Cisne’s course will zig-zag on its way up river.  Of course, that’s not how a vessel actually moves. This also means that for part of the turn, she could be in gunnery range, or clear of a shoal, while at the end of a turn, her position will suddenly change, potentially putting the ship in a hazard the helmsman could have avoided in reality. Those of you who have sailed (or flown airplanes for that matter, the principal is very similar), know that to track a straight course, the helm/rudder is held deflected to adjust the ship’s heading to correct for the current as the ship moves forward on the desired course.  In my day job (airplane pilot), we do something very similar when we navigate with strong crosswinds: the airplane’s heading is adjusted to remain on the desired course.  While it’s not depicted this way in any games that I’ve played, the true effect of a current isn’t really on position, but on speed. A sketch of the vectors involved illustrate this quite well. In aviation, we call this a “wind triangle” problem, in marine navigation, it’s called “set and drift”:

The mathematically inclined can use the Pythagorean Theorem to determine the actual ratios of ship speed to its progress along the plotted course, but clearly the ship in question is in effect, moving “slower” along its course.

So, once we had determined that speed is the most relevant adjustment to make to account for current, the question remained, how best to incorporate it? You can probably guess the solution. In keeping with the design goal of simplifying where possible to maintain continuity with the elegance of the Flying Colors core system, we have adopted the following: Ship’s pointing “upstream” have one less movement point than normal, and those pointing downstream have one more. Thus, reimagining the earlier example, instead of moving ahead 4, then displacing one hex at the end of the turn, Cisne has only three MP to spend while she points into the current or within one hex side of the current direction:

The ship’s position on the map throughout the game turn, and therefore the depiction of its course, are much more realistic.  What of ships that are adrift, or even becalmed? They will displace one hex in the direction of the current at the end of the turn, which could cause them to drift over a shoal or towards (or perhaps away from) some other hazard. By the way, all of these changes will be summarized on the player aid cards for the game, and we hope, with some practice, the new rules will become as comfortably familiar as the core rules have been since the inception of the series.


Gunboats play a prominent role in many of the battles portrayed in USC, far more important in this game than in any previous volume of the series. While the FC system was originally conceived to model large, line-of-battle engagements such as Trafalgar and the Glorious First of June, it is a tribute to the flexibility of the design that with a few minor adjustments, it can recreate even fierce melees between schooners and oared gunboats in the rivers of South America.

Players familiar with the FC system recall that gunboats have always been a part of the game (the “T” rated ships) but because of their prominent role in USC, we felt the need to further refine some of their characteristics.

This is the Battle of the Jaguari Creek, fought between the United Provinces of the Rio de la Plata (UP) and the Empire of Brazil during the Cisplatine War (1815-1828).  The front line of each side’s fleet are composed entirely of gunboats, the Argentine’s single pivot-gun armed boats, while the Brazilians boats are each armed with two pivot guns, one mounted in each broadside.

Historically, this battle was a frustrating failure for the Argentine flotilla, as the gunboat line exhausted themselves rowing into range of the enemy and the ensuing exchange of fire did little damage before a storm separated the two sides.  The bow mounted guns of the Argentine boats, in common with many gunboat designs from this period, were intended to allow the boats to point the guns primarily by pointing the bow of the ship at the target. Under the existing FC series rules though, the UP gunboats would fight at a disadvantage if the controlling player employed historical tactics in that gunfire outside of the broadside arc is performed with negative DRMs. Under the new rules, single-gun gunboats, which we define in the rules as (1-T) vessels with oar power available, are allowed to fire without penalty into their forward arcs like so:

While other T rates, including the (2-T) gunboats of the Brazilians use the more conventional broadside tactics from the existing rules. The rate of fire of single-gun boats is limited to a single shot per turn as well, and because they are firing generally along their long axis, there are no wind effects of their fire, like there is for broadside armed ships.

As I write this article, we are seriously considering some changes to the core rules that will allow an additional sail state (“Short” sail) for use in limiting ship speed when operating in shoal waters and to reduce the risk of rigging damage when fired upon. If adopted, the rules would be portable to the earlier games of the series if desired and special markers provided to indicate Short Sails. But more about that later…

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2 thoughts on “New Features in Under the Southern Cross Part II

  1. Thanks very much for the update! When Under the Southern Cross was first announced on P500 I wasn’t particularly enthusiastic about the topic, but I pre-ordered it anyway because I have all the other games in the Flying Colors series, and I thought, well what’s a collection unless it has all of the editions. Now with this report about how current is handled and the gun boats, plus the short sail idea, I’m really excited about the game! I’ve also been delving into the history of the battles a little, and not only will USC be a fine addition to my collection, I’m eager to put the game on my table to explore these battles! Thanks again for the report, and here’s hoping more pre-orders will come flooding in!

    • Thank you, Jan for the kind words! It’s been fun seeing the work of many years research slowly becoming reality.

      I think you’ll like the variety of battles that are included.Not only are river fights included, but there are of course more traditional ocean battles as well, and more than a dozen one-on-one and two-one-two ship duels, that reintroduce the special rules, map and cards from Serpents of the Sea.

      I can recommend the work of Brian Vale for the best information in English on the Argentine/Brazilian part of the story. For the other battles, sources in English are pretty rare and not terribly detailed. If, however, you can read Spanish (or Portuguese), there are great many good sources!