Scaling & Pacing a Seacrawl

[Sparky McDibben]

So, weird question for y'all.

I'm planning on running a hexcrawl at sea for my players. Looking at Ghosts of Saltmarsh, your basic sailing ship can travel 120 miles per day. My map is about 15 x 22 hexes (any smaller and I'm going to run into problems reading the hex numbers).

My question: how big should my hexes be? I'm looking in multiples of 12 miles, since the ships can cover distances per day in multiples of 24. I've done some math, and these are the ranges:

12-mile hexes: Sailing ship can cover 10 hexes a day, crossing the whole map in about two days
24-mile hexes: Sailing ship can cover 5 hexes a day, crossing the whole map in about four days
36-mile hexes: Sailing ship can cover 3 1/3 hexes a day, crossing the whole map in about six days

This is problematic for a number of reasons. One, it means I have to use a different scale for overland and at sea exploration, which means I need different maps. Two, I'll run into problems with pacing. I'll either need to stock each sea hex with several items (especially if I'm using a 36-mile hex!) or bump up the likelihood of triggering an encounter per hex to avoid pacing that seems glacial, or both.

Follow up questions: Has anyone else seen anything that could be used to run a seacrawl? Is there a better structure to use? How would you solve the problems I've outlined?

[Lunali]

So, weird question for y'all.

I'm planning on running a hexcrawl at sea for my players. Looking at Ghosts of Saltmarsh, your basic sailing ship can travel 120 miles per day. My map is about 15 x 22 hexes (any smaller and I'm going to run into problems reading the hex numbers).

My question: how big should my hexes be? I'm looking in multiples of 12 miles, since the ships can cover distances per day in multiples of 24. I've done some math, and these are the ranges:

12-mile hexes: Sailing ship can cover 10 hexes a day, crossing the whole map in about two days
24-mile hexes: Sailing ship can cover 5 hexes a day, crossing the whole map in about four days
36-mile hexes: Sailing ship can cover 3 1/3 hexes a day, crossing the whole map in about six days

This is problematic for a number of reasons. One, it means I have to use a different scale for overland and at sea exploration, which means I need different maps. Two, I'll run into problems with pacing. I'll either need to stock each sea hex with several items (especially if I'm using a 36-mile hex!) or bump up the likelihood of triggering an encounter per hex to avoid pacing that seems glacial, or both.

Follow up questions: Has anyone else seen anything that could be used to run a seacrawl? Is there a better structure to use? How would you solve the problems I've outlined?

Trying to do travel with the recommended number of encounters per day makes for a world where travel is extremely dangerous. If you're going to base your campaign around it I'd suggest using different rest rules. As for the hex scale, I would go with 6 times the scale you use for overland travel.

[Boci]

Trying to do travel with the recommended number of encounters per day makes for a world where travel is extremely dangerous. If you're going to base your campaign around it I'd suggest using different rest rules. As for the hex scale, I would go with 6 times the scale you use for overland travel.

Depends on the encounter table you use. The Sylvan woods encounter table in the DMG has 19 encounters only a few of which are explicitly dangerous, stacked to be the least likely rolled.

[Lunali]

Depends on the encounter table you use. The Sylvan woods encounter table in the DMG has 19 encounters only a few of which are explicitly dangerous, stacked to be the least likely rolled.

True, but for travel to be reasonably safe for non-adventurers, you have a combat encounter every few days at most. This makes for a pretty low encounter rate for adventurers.

[Tanarii]

24 for the large scale maps. That's also the distance covered in a single days normal pace March. For land based exploration (islands, inland expeditions) you'll want to map local land areas in 6 mile hexes to allow for granularity of Fast or Slow paced travel, plus forces marches of 2 hours. As well as it being more fun to make an exploration choice every 2 hours and more precisely locate multiple adventuring sites / encounters in the local area.

Edit: for random encounter checks, divide up your map into wilderness/frontier/civilized and set different encounter rates for the different areas. You might not even want to bother in civilized / well patrolled areas or sea lanes.

Edit 2: per the PHB a sailing ship covers 2 miles an hour.

[Sparky McDibben]

Ok, this is good feedback, because you're both right; I forgot to tell you the design intent!

I'm looking for an experience where (h)exploration and discovery are key. Where the heroes are constantly discovering things, even in territories they're familiar with.

I think I can generate a hex key that delivers that (h)experience, leveraging some excellent work done by the Alexandrian. But, all that discovery relies on the heroes getting through at least 3-4 hexes per day, and more is better (more hexes equals more location and encounter checks, and more cool stuff to find).

This is where pacing gets tricky. I'm envisioning a play sequence that will generate encounters where exploration, combat, and social play all mix (see, any episode of Star Trek). But, if they're only going through one or two hexes, they might not find anything, which equals boring play. Conversely, too much equals overwhelming play, not to mention a lot for me to keep track of.

Furthermore, I don't think it feels like heroic exploration if you can cover the whole map in a day or two. Which is why I came to the brain trust here at GitP!

[Laserlight]

120 miles a day would be "if the wind is favorable all the time". That can be true if you pick your route carefully and you're in an area with well known and reliable winds. I assume that if the area was well known, they wouldn't need adventuring.

Probably it's also "if you're sailing at the same speed day and night." Merchantmen might well reduce sail at night, both to avoid running into unseen trouble and as a precaution in case of rough weather coming on them while they crew was asleep. (A warship, which is normally heavily crewed, doesn't have to worry about it as much).

[Sparky McDibben]

Edit: for random encounter checks, divide up your map into wilderness/frontier/civilized and set different encounter rates for the different areas. You might not even want to bother in civilized / well patrolled areas or sea lanes.

Edit 2: per the PHB a sailing ship covers 2 miles an hour.

Excellent suggestion, thanks! I'm using the movement rates from Ghosts of Saltmarsh, but using different statblocks for a sailing ship isn't a bad idea. Thanks!


120 miles a day would be "if the wind is favorable all the time". That can be true if you pick your route carefully and you're in an area with well known and reliable winds. I assume that if the area was well known, they wouldn't need adventuring.

Probably it's also "if you're sailing at the same speed day and night." Merchantmen might well reduce sail at night, both to avoid running into unseen trouble and as a precaution in case of rough weather coming on them while they crew was asleep. (A warship, which is normally heavily crewed, doesn't have to worry about it as much).

Well-known and not dangerous aren't exactly the same things, but I think you hit on an interesting point. Well-known to whom, and not dangerous to whom are good distinctions! An example is a heavily patrolled stretch of water that sees merchant and naval traffic. This is very well-known territory, but dangerous for pirates. Another good idea is to seed the area with fixed, mobile, and semi-mobile navigational hazards. Excellent input and thank you! Your idea about stopping for the night is a good one, too, because it's a choice the heroes can make. How to make it meaningful?

I could say it shifts the threat landscape. Traveling by night makes navigational hazards more likely, but anchoring leaves you more vulnerable to hostile action? Still, that's not a great choice. Any other ideas I can use to make the choice matter more?

[Laserlight]

Your idea about stopping for the night is a good one, too, because it's a choice the heroes can make. How to make it meaningful?...Traveling by night makes navigational hazards more likely, but anchoring leaves you more vulnerable to hostile action? Still, that's not a great choice. Any other ideas I can use to make the choice matter more?

Three choices:
1) anchor in a bay / atoll / protected waters whenever available. Greatest protection from weather, best opportunity to resupply, but slows your travel rate and exposes you to any island inhabitants.
2) easy sail at night--almost certainly not anchoring because you're in deep water ( although you could use a sea anchor, which slows you although it doesn'tstop you). Slows your journey, some risk of weather.
3) full speed. Gets you there the fastest, unless of course a sudden squall costs you sails or a topmast because your crew was asleep, or unless you run onto a reef in the dark.

So how much risk do you want vs how much speed?

[Lunali]

Ok, this is good feedback, because you're both right; I forgot to tell you the design intent!

I'm looking for an experience where (h)exploration and discovery are key. Where the heroes are constantly discovering things, even in territories they're familiar with.

I think I can generate a hex key that delivers that (h)experience, leveraging some excellent work done by the Alexandrian. But, all that discovery relies on the heroes getting through at least 3-4 hexes per day, and more is better (more hexes equals more location and encounter checks, and more cool stuff to find).

This is where pacing gets tricky. I'm envisioning a play sequence that will generate encounters where exploration, combat, and social play all mix (see, any episode of Star Trek). But, if they're only going through one or two hexes, they might not find anything, which equals boring play. Conversely, too much equals overwhelming play, not to mention a lot for me to keep track of.

Furthermore, I don't think it feels like heroic exploration if you can cover the whole map in a day or two. Which is why I came to the brain trust here at GitP!

I think I would go with at least the 36 mile option then, 40, 60, or even 120 would also be reasonable. Remember that the number of hexes they visit per day isn't nearly as important as the number they visit per session. If they go a few days without finding anything, that may be boring play, but it's also only a couple of minutes at the table as long as you don't bog it down.

Alternatively, throw the map out and go for the more narrative version that would be appropriate for something like Star Trek.

[Tanarii]

Excellent suggestion, thanks! I'm using the movement rates from Ghosts of Saltmarsh, but using different statblocks for a sailing ship isn't a bad idea. Thanks!
Interesting. I hadn't noticed they boosted it. Comparing to a human base speed, it looks like it should be 4.5 miles an hour, rounded up. And then they used the rounded up value to go to 120 miles.

So it probably should be:
Into wind - 1.5 mph / 36 miles for 24 hours
Normal - 4.5 mph / 108 miles for 24 hours (3*36)
With wind - 6 mph / 144 miles for 24 hours (4*36)

Based on that I'd make your Sea Map 36 mile hexes, since all sailing ship corrected rates are divisible by that.

Edit: I don't see rules in gm for tacking a max of 45 degrees being necessary to go into the wind but I only skimmed.

[Laserlight]

Sailing ships were slower than most people seem to think. They weren't used because they were the fastest means of transport (which depended on the route); but they were vastly more efficient, in terms of cost per ton/mile, than land transport.


Ellmers (197: 250) has compiled a table of documented voyages with their distances and the length of time they took. From this it seems that an average 'speed made good' of three to six knots was to be expected. The difference between a sailing ship's actual speed through the water and 'speed made good' is brought about by three factors. The first is the impossibility of sailing directly into the wind. It is necessary to sail a zig-zag course ('tacking') to windward. (The other two factors are current and leeway).

Feel free, when it suits you, to say "You're making 2 knots through the water, but you're tacking and you're also going against a 1 knot current, so...that island on the horizon isn't much closer, four hours later."

[Lunali]

Sailing ships were slower than most people seem to think. They weren't used because they were the fastest means of transport (which depended on the route); but they were vastly more efficient, in terms of cost per ton/mile, than land transport.

(The other two factors are current and leeway).

Feel free, when it suits you, to say "You're making 2 knots through the water, but you're tacking and you're also going against a 1 knot current, so...that island on the horizon isn't much closer, four hours later."

Even with tacking and a 1 knot current, if you're managing 2 knots through the water after 4 hours you should be pretty close the the island that was about 3 miles away.

Sailing's greatest advantage in speed was in the ability to travel three times as long each day, which is represented in the rules.

[Laserlight]

Even with tacking and a 1 knot current, if you're managing 2 knots through the water after 4 hours you should be pretty close the the island that was about 3 miles away.

The horizon is rather more than 3 miles away. Exactly how far depends on the height of your masthead.

And if you're doing 2 knots through the water, but that's all zigzagging as you're tacking, and you also have an opposing current, you could easily end up farther away than when you started. "Speed through the water" only matters if you're in a chase; "distance made good" is what gets you to your destination.

[BurgerBeast]

You need to spend some time thinking about how frequently you want the PCs to discover locations or have encounters. It’s nice to have hexes within which you can build simple time-costs for things like travelling through a hex and exploring a hex in search of interesting things.

It’s totally possible to run with 120-mile hexes if you’re doing sea-based and there’s not much on the open sea. You could still check multiple times per hex for encounters.

If you want there to be multiple points of interest within smaller areas, you should move to smaller hexes.

I like my hexes to be around 1/6 of a day’s travel distance. So usually about 4 miles (but maybe 2 miles in the jungle). Then I tend to say the party can spend 4 hours exploring a hex, during which time they find a new location in the hex.

I would let the density of interesting geographical features determine my hex size. I like three interesting locations per hex.

It seems to me that there’s be significantly less interesting features per area on the open sea... but obviously that depends on multiple factors.

[Tanarii]

Feel free, when it suits you, to say "You're making 2 knots through the water, but you're tacking and you're also going against a 1 knot current, so...that island on the horizon isn't much closer, four hours later."
From my reading of that quote, that's 3-6 knots (a bit more than 3-6 mph) after accounting for factors.

[Sparky McDibben]

This thread is super useful, y'all, thanks!!!

I'm seeing three points of commonality in what y'all are saying:


I'm going to need separate maps of the islands at 6-mile hexes. Not ideal, but I'm glad no one could figure out a better way to do it!
If you want the map to feel bigger, they shouldn't be able to sail straight across it; clutter with islands, weather, naval patrol routes, etc. Excellent ideas!
Finally, there are variable factors to ship travel, which means it's time for my favorite RPG tool: RAAAAAAANDOOOOOOOOMMM TAAAAAAAABBLEEEEEEEEEEEESSS!!!!


I could have the random tables generate wind and sea currents...or I could skip straight to the thing I actually care about and see what their speed is. Thinking a 2d6 table, with 2 being 25% speed, 3-5 being 50% speed, 6-8 being 75% speed, 9-11 being 100%, and 12 being 125%. So they're always making some progress, but not necessarily good progress.

Now, check frequency...once per hex is pretty good; if we're using 36-mile hexes, though, that could mean they spend an entire day in a single hex if they roll a 2. But that has just the same likelihood of rolling a 12, going 5 miles an hour over 24 hours, and covering like 4 hexes.

Maybe I should give them a bonus to Perception checks based on speed? Except that's a lot to be determined by a random table, with no choices made by the characters. Thoughts?

[da newt]

If the area is known, decent charts exist, and the CAPT is experienced, they will know the major currents and trade winds, and will route accordingly. For example the surface currents in the north Atlantic flow clockwise around the perimeter with minor variations in location and speed and have for hundreds of years, the trade winds in these latitudes go this way, here there are doldrums (little wind) here the trades go the other way but there are some variations with season etc (this is a bit of an oversimplification, but not much).

On an earth like planet, exploration should be concentrated near shore / features - the open ocean contains very little worth noticing for a ship transit - it's mostly just blank. Out there weather is your primary concern. Open ocean transits are boring. But your world will be however you want it to be.

I'd recommend generous time jumps where you simply hand wave distances covered in X amount of time to get the party to an area where something is.

[Sparky McDibben]

If the area is known, decent charts exist, and the CAPT is experienced, they will know the major currents and trade winds, and will route accordingly. For example the surface currents in the north Atlantic flow clockwise around the perimeter with minor variations in location and speed and have for hundreds of years, the trade winds in these latitudes go this way, here there are doldrums (little wind) here the trades go the other way but there are some variations with season etc (this is a bit of an oversimplification, but not much).

On an earth like planet, exploration should be concentrated near shore / features - the open ocean contains very little worth noticing for a ship transit - it's mostly just blank. Out there weather is your primary concern. Open ocean transits are boring. But your world will be however you want it to be.

I'd recommend generous time jumps where you simply hand wave distances covered in X amount of time to get the party to an area where something is.

That's a good take, and thanks! I'm thinking this will be in an area similar to the Indonesian Archipelago, so the sea won't be terribly deep most of the time. Lots of island chains, volcanoes, et cetera, to generate constant discoveries and continual content. But I think that in a fantasy world, there should be just as much to discover beneath the sea as above it (which is one of the reasons the floor will be relatively shallow). Also, there's plenty to see on the sea, especially in a D&D world, whether that's just color (merfolk running near the ship, flying fish schools), tracks or evidence of other actors (flotsam, jetsam, seafloor wrecks, the wake of a vessel stirring up bio-luminescent algae), or the other actors themselves (a pirate ship emerging from the storm, a dragon turtle stalking the sea lanes, or sahuagin swarming the decks).

But with the various magical influences, I think you can create a swirling series of currents, storms, and other factors. Though that does beg the question of why anyone bothers sailing here. Gotta be because going around it either is (a) prohibitively more expensive (possibly a dragon turtle or something that requires tribute, or just it takes an inordinate length of time), or (b) every other passage is worse (more pirates, less certainty, or both).

So for whatever reason, this archipelago sits amid a confluence of factors that makes it the best possible route for maritime shipping. Or, maybe it's just the best possible route for fast, high-value cargoes? Maybe this is where the stuff that spoils quickly has to be sent, including high-value magical components, soldier's pay, etc. Ooh...this is interesting. Man, this is good stuff. Thanks, guys!