How do I load out a Large Sailing Ship?

I’ve been running sample calculations for trade ships, and I’m having trouble figuring out how to take advantage of the extra shipping capacity of a large ship.

To start, let’s assume we have a Class II market. This is a pretty sizable market, and is probably loading dozens of ships a month, so I figure it’s large enough that it should be sensible to send a large trade ship there, or even a small fleet of trade ships.

A market this size is going to yield 2d4+1 merchants (let’s call that about 5), and each of them will have about 4d6 (average 14) loads. If each load weighs an average of 70 stone, then I get around 4900 stone of cargo, assuming that all the reaction rolls fall my way (not impossible, with a good CHA bonus, but still optimistic).

That about half-fills a small sailing ship. I can fill the other half with an equal number of shipping contracts, plus a few odd passengers. This works out nearly perfectly to match the listed 10,000 stone capacity of my small ship. Great!

Now I’m ready for the big leagues. I buy a large sailing ship, with 30,000 stone capacity. But I’m still making all the same rolls above. So now my large ship is only 1/3 full. How do I find the cargo for the other 2/3rds of the space? I’ve already saturated the markets for that month!

Even if I run the same calculations for a Class I market, I still only about half-fill the ship. Worse yet, really good traders tend to be able to procure cargo that consists mostly of valuable luxury goods that have very low weight. That gives them even less need for a large trade ship.

I can avoid this whole problem by running two small ships, and having them arrive on alternating months. But it seems like cheating to get twice as much available cargo this way, and I don’t see why it should be necessary from a simulation standpoint. Showing up with two different small ships rather than one large ship shouldn’t change any need for transportation services, from the perspective of a selling merchant!


  1. Large sailing ships are only meant for routes that make lots of stops, not just running between two ports.

  2. Large sailing ships stick around in port for multiple months, building up a full hold. (While any perishable goods are protected by some kind of food preservation cantrips?)

  3. Large sailing ships hire additional traders and procurement specialists to fan out around the city and locate more local merchants faster. (In game terms – you can split up your party and have them each locate the full number of merchants, using the best CHA character in each sub-party.)

I suspect that historically the answer was usually #3, so I think that’s the way I’m going to house-rule the problem. But I want to make sure I’m not overlooking some mechanism already in the rules that solves this problem.

I’m actually pretty curious about this too. I’m really into deconstructing the source of “Campaign” XP.

My best guess is that a large sailing ship rolls along a coastal/island region with several cities, taking shipping contracts along the way of course, but also buying anything cheap in that market and waiting until they arrive in a market where that good is in demand to offload it. It would certainly make for a complicated caluclation of campaign XP though!!!

1., 2., and 3. all sound likely.

Also: are you accounting for the weight of water and food for the entire crew?

Are we supposed to account for that sort of thing? I know for rowing based power there’s supposed to be extra weight because of all the water needed to keep the rowers hydrated, but I guess I assumed the weight of water and rations would be negligible compared to the weight of the crew and the cargo.

I’d say it might make more sense to just reduce the cargo hold some amount to focus only on the “usable” cargo space, but then I guess that would abstract away the dynamic between long and short journeys.

Historically, this problem was solved by warehousing.

You start in city A which has a negative demand modifier for the item or items you are shipping.

You ship it to your warehouse in city B which has a positive demand modifier.

You then sell the item(s) over the course of the next few months; your ship(s) can either continue the round trip if the cities are far enough away, or it can visit a third or even fourth city where you, ideally, own more warehouses.

As far as food and water, I assume you are intended to account for it, but you are also correct that it’s minor compared to the cargo capacity of a large sailing ship. A large sailing ship has a crew of 20 sailors (not sure if that includes captain and navigator; I am assuming it does but it would make very little difference if it does not). Two months worth of food and water for 20 men weighs 1500 stone. (1 stone of water plus 1/20th stone of barrel plus 2 pounds of food, times 20 people times 60 days.) The cargo capacity is 30,000 stone.

You need 1 stone per day per person on board of food (2 lbs) and water (1 gallon); see page 94. Rowers need 3 gallons of water per day, so it’s 3 stone per rower per day (page 96).

Granted, on a small sailing ship, that’s only 12 stone per day for the crew, which is a tiny fraction of the capacity. Even if you stock up for 30 days, that’s only 360 stone.

Generally, you’re only going to carry so much: never leave port with more than 60 days per person of iron rations (they spoil after two months; and after one month you get scurvy), and you’re probably planning to make landfall here and there (as often as you like on coasts) to get fresh water (free from any lake or river etc.). Open ocean voyages are harder - running out of fresh water was a real danger.

Dang you, cleverly accounting for barrels!

Re: Warehousing, aha, it sounds like somebody else has played Patrician IV (or any other number of similar economic sim games). This immediately makes me wonder what happens when you go and buy your iron ore from a mining town where the demand modifier is -5 and ship it to a city big enough to hire an army of master blacksmiths to craft armor with it.

One thing to keep in mind in some of these more advanced discussions is that mercantile ventures award XP specifically for journeys that a PC or group of PCs and henchmen are personally responsible for, and the extent to which it rewards you is based on how profitable it is in a short period of time. Perhaps from this vantage, the massive holds of the sailing ship aren’t as relevant to personal growth as negotiating ability and finding large price differentials on expensive goods.

This is another example of what ought to be a diminishing returns situation of the same type I was puzzled about with thief guilds earlier.

Having 10 traders out scouring the city ought to turn up a larger number of opportunities than sending a single trader, so there ought to be a bonus for bringing along a larger crew of trade-skilled PCs and henchmen. But it probably shouldn’t be a strictly linear function, since some of them would end up competing over the same merchants. It needs to be a function that rises sub-linearly, and eventually saturates after every last merchant in the city has been contacted.

I like to default to using a square-root approximation in situations like this. For example, if you have a crew of 15 characters, you can send out about 3-4 groups of 3-5 members each, since sqrt(15 = 3.87). That feels just about like what I’d expect a real trading ship would do, if it wanted to quickly locate a lot of cargo after arriving in a foreign port.

Once you had established yourself as a regular participant in the new market, you’d want to set up your own trading company facility with warehouses and offices and local employees, so ships would have cargo ready to load the moment they arrived. But as “adventurers” I assume a big part of play is setting yourself up with no starting assets, in the early period before you’ve arrived at a higher level of organization.

When I modeled the revenues of large sailing ships, I assumed they traveled from one Class I route to another, a distance of 500 miles which took 4 weeks. At each port, they stayed for three weeks, where they picked up 6 passengers and 9 shipping contracts, then filled up the rest of their cargo bay with arbitrage cargo. I assumed margins on arbitrage work at 5%. As a result, most ships make most of their money from shipping fees, not from arbitrage.

One of the interesting questions is how much trade should be going on in any given city. In a civilization of 6M families there is approximately $4.3B gold pieces of net worth, or 716 gp per family.
From there, the bottom 77% own 15% of the wealth.
The top 23% own 85% of the wealth.
The top 5% own 75% of the wealth.
The top 2% own 55% of the wealth.

Let’s assume city dwellers are drawn from the top 23%, who therefore own $3.65B gold pieces across 1.4M families. That means the average city family’s net worth is 2,607gp. That, in turn, translates into a per-capita monthly income of about 80gp per city dweller (remember ACKS’s secret 1/33 ratio) per month.

That gives us a sense of the demand for goods of a city - 80gp per family. A Class I city with 20,000 families therefore has a demand of 1,600,000gp per month for goods. An average load of merchandise is worth 180gp, so approximately 8,888 loads of merchandise can circulate through a Class I city each month.

Per ACKS, in a Class I city, average number of merchants willing to do business with a PC each month is 9, while average loads per merchant is 27, or 243 loads per PC. 243/8888 = .027, or 2.7%. So at any given time, there are actually probably (9/.027) 333 merchants available, enough for (1/.027) 36 PCs to do business.

A typical large merchant ship carries about 350 loads, so that would be 25 large sailing ships per month in port, or 300 per year. Is that plausible?

Rome, when it peaked at a population of 1,000,000 was served by 1,200 large vessels carrying food each year. At 1,000,000, people, that is 200,000 families, or 10x the size of our basic class I city. So we project 3,000 vessels docking at Rome per year. Looking at the Merch tables, about 30% are foodstuffs of various sorts, so that would suggest ~ 1,000 food vessels, not too dissimilar from our totals.*

*To be fair, ACKS skews grain to a smaller proportion and increases salt, meat, beer, etc. to a higher proportion than history would suggest. This was purposeful as otherwise the merchandise tables are rather dull… Oh, more grain!

It’s worth noting as well that virtually ALL trade was conducted in the various towns and villages of the landscape. So the amount traded could actually be higher.

The bottom 4.6M families own $645M in wealth, or 143gp each. That means they earn 12gp per month. Of this, they consume 3gp for themselves. The remainder is tradeable - 9gp per month in demand.

So the overall tradeable goods are (4.6M x 9gp) + (1.4M x 80gp) = 41.4M + 112M = 153M gp in goods being traded in town. With a population of 6M families, 600K families live in town, and if we assume ALL trade is in towns then trade per town family is actually more like 255gp, or about 3 times more.

In any event, the point is that it’s quite unlikely your PCs will hit the point of diminishing returns on trade…

I had been operating off the assumption that it would be pretty rare to find two Class I markets particularly close together, and that the most profitable trade routes would be connecting a Class I market to its Class II satellites. In my defense, that seems to be supported in the Core rules: “Large sailing ships and huge 30-40 wagon caravans are assumed to ply trade routes between Class I and II markets, while small sailing ships and caravans ply the secondary trade routes between Class II and III markets.” That’s at least part of the reason for the discrepancy. Yes, I could probably buy more cargo at the larger market, but then I’d still be stuck trying to sell it at the other end.

I always enjoy these posts that peel back the rules to reveal some of the demographic scaffolding, and I admit that I probably write some of my questions just to goad Alex into writing them!

In the case of my current campaign world’s example trade route, which runs from a large city with a population of about 60k families to a smaller city with a bit over 5k, the bottleneck for finding merchants is definitely at the smaller city. It sounds like a city that size would probably support around 10 adventuring traders, instead of 36. That suggests I could probably have two or three ships running through there every month without too much disruption, but trying to go too far beyond that would require gaining some kind of trade monopoly over regional traffic.

I still imagine that new adventurers have to be in competition with existing trade companies with more established reputations. So even if the city could hypothetically support 10 adventuring crews, getting all of the merchants to switch to new shipping arrangements (mine!) would be a bigger challenge. So I still envision competition would be tight enough to create an experience of diminishing returns, with economic expansion being subject to marginal rather than absolute demographics. (Not “how much total shipping can happening here”, but “how much can shipping expand beyond where it already is”.) If you send in multiple ships with multiple crews all competing for the minority of merchants who aren’t locked up in contracts with an existing preferred carrier, then you risk cannibalizing your own expansion.

That being said, ignoring this kind of complication makes the system less formidable, and I imagine that there’s not much of a market for RPG players who would worry that ACKS is still an insufficiently detailed simulation engine for trade.

“I imagine that there’s not much of a market for RPG players who would worry that ACKS is still an insufficiently detailed simulation engine for trade.”

For whatever reason, that quote really made me laugh!

Hmmm… these numbers to yield some interesting perspective on the hijink issues we’ve seen. If an urban family has an average disposable monthly income of 80gp, pulling 40kgp in monthly hijinks is consuming about half of the earnings of a 1000-family town, which is… substantial. And at >80kgp / mo in hijinks, your average citizen is taking a net loss per month and is likely forced to either go into debt or flee.

Where did you come up with 40,000gp in monthly hijinks for a town of 1,000 families?

Is that assuming a thieve’s guild that is made up of nothing but spies-for-hire? I responded to an earlier thread on this topic… I think that something like that would be dynamically unstable within the game world and prone to collapse. Just as the nobility, army, and other hierarchies in ACKS assume a progression of 0 level to high level, so do the thieves’ guilds, or they fall apart.

Keep in mind you can find the Maximum Number of NPCs in Various Realms in the chart in “Secrets” Chapter. Thieves are about 20% of NPCs. Since there is 1 4th level character per 375 people, there ought be no more than 1 spy per 1,875 people or 1 per 375 families.

Following ACKS demographics and about six pages of linked spreadsheets I worked out that the Thieve’s Guilds in cities earn the following
Class I (20,000 families): 107,1010gp/month of 1,600,000gp per month
Class II (5,000 families): 42,565gp/month of 400,000gp per month
Class III (2,500 families): 23,173gp/month of 200,000gp gp per month
Class IV (625 families): 7,912gp/month of 50,000gp per month
Class V (250 families): 3,087gp/month of 20,000gp per month
So it always hovers around 15%.

Yeah, those were the sort of numbers we were seeing with all-spy guilds, if I recall correctly (it was a while ago, but some rough back-of-envelope math suggests that 100 spies (cap for class IV market), each Spying with a 25% success rate and earning 4 * 700 gp in expectation per success, could pull about 70kgp / mo, minus wages, fines, bribes, and legal fees. My players did not have maxed-out all-spy guilds, but many of their operators rolled Skulking or Lip Reading during random proficiency selection or selected them while levelling, and they tended to mitigate legal fees via control of the courts).

Limiting the number of available spies sort of conflicts with the availability rules, though, unless you assume that an available spy across months is the same one and won’t replenish if hired (which doesn’t seem to be the assumption with most other specialists, I think?). My players were importing spies (and cataphracts) from across the land, including a semi-distant class II market, in any case… I do not recall the total population of the area they were recruiting from, but it’s possible that their number of spies was within tolerances for their recruiting region as a whole (just exceptionally concentrated). Would be interesting to see DaW:C hiring logic applied to ruffian recruiting; I might have to take a look at that.

I rather like a simple “12 gp per family per month is consiered a normal level of crime in a city with established guilds, and going beyond that will have suitable consequences” rule, though.

There has to be some sort of cap. Even if I managed to perfectly correlate the number of ruffians such that hiring within a Class III market you can’t hire so many spies as to disrupt the game, that wouldn’t prevent a player from hiring spies in a Class I market and then bringing them to a Class III market.

Here’s a new RULING: Maximum Syndicate Membership is measured in levels of experience. 0-level ruffians count as 1/2 HD for these purposes.

EXAMPLE: Viktir establishes a hideout in the town of Cyfaraun, a class IV market. Initially, he spends 10,000gp on his hideout. Based on the value of his hideout, the maximum membership of his syndicate is 50 class levels. He hires 10 spies (40 class levels) and 20 carousers (10 class levels). Later, he spends another 10,000gp on his hideout, increasing its value to 20,000gp. The maximum membership of his syndicate rises to 100. He hires 20 footpads (20 class levels), 20 more carousers (10 class levels), and 5 more spies (20 class levels). The year following, he expands his hideout to a 75,000gp mansion. However, the maximum membership of his syndicate does not increase, because a Class IV market can only sustain a 100-member syndicate.

Hmm… and then as your ruffians level, you go over cap and some of them leave of their own accord, presumably?

Sounds about right to me - if there’s no openings at their level in the current syndicate, they seek opportunities elsewhere, or go make their own (adventuring, banditing, becoming enemies in modules, etc.). It’s obviously a rough abstraction, but gets a plausible result.

Also, Alex, great rule (even if it’s just a stopgap); I’m nowhere near needing to tackle this problem, but I was thinking about tying maximum membership to guildmaster level or something (which would also encourage PCs to delegate “local branch” guilds to henchmen).

Not sure this would work out at all, but just as a thought experiment to turn this around a bit:

Is there any value in having market availability for hijinks? A “Black Market Availability” table, as it were?

The current system only accounts for success/failure, and not if there’s anything to do in the first place.

Given the smaller market sizes, is there always really someone around who wants someone assassinated, or someone doing something worth spying on, etc. etc?

The assassinating/spying hijinks certainly imply there’s a third party somewhere paying the guild for this information, and in even the larger markets there’s not going to be a number of them every month that just so happens to meet or exceed the number of asassins/spies any guildmaster can conceivably hire, unless the expectation is that you’re actively soliciting for targets. (hey buddy, want someone dead? dirty deeds, done dirt cheap, here’s my card)

Smuggling & Stealing may have that somewhat baked in, already - over in Mercantile Ventures we’ve already rolled for the number of merchants working and loads being traded - should hijinks work against that number (or, a second Market & Merchants table based on the number of merchants willing to shave some costs with smuggling, perhaps) rather than creating their own economy out of whole cloth?

That all being said, that could open the hijinks system up into more of a “Shadow Ventures” chapter that mirrors the Merchant Ventures - and attach some rules up onto that that once your hijink activities start to brush up against some limitation via market class the blowback from the “real economy” and the authorities starts to affect the guild, either via cumulative penalties the bigger you get or via DM action.