Building an Aquatic Hexcrawl

[Flallen]

The game I am running is going to have the party doing a lot of diving under water to search for a specific shipwreck. I want to run this part of the campaign as a hexcrawl in order to give them some variety in experiences since they've had some fairly linear campaign in the past and have also done a bit of the mega-dungeon crawling stuff. The party is level 8, so the way am hoping to run this is that they could defeat the Aboleth I've got planned for them.

Has anyone done a semi-hexcrawl like this before? I'm finding the amount of work this takes is way higher than just running a few pre-planned encounters. How did you manage the prep work?

Any ideas for points of interests or interesting bits of subnautical intrigue or cool creatures to stuff in as top predators?

[JNAProductions]

Look at the game Subnautica for big scary monster ideas.

I'd google it myself, but I'm scared. :P

[Sparky McDibben]

I tried doing this myself, but my reach exceeded my grasp.

My thoughts on hexcrawls are that they are heavily front-loaded in terms of prep, but once prepped and stocked, you can run them with a minimum of at-table prep or improv. They're really good that way. They also give you a solid mechanical structure for moving around the map, something which is missing in D&D currently. For an example, check out the Alexandrian's blog on this.

My tips are to keep the maps small, make sure content isn't self-deleting (like a lost triton you have to guide back to safety), and if there are lairs on the map, make sure the hexes around that lair have that monster on their random encounter tables (or the monster's tracks).

As far as ideas, here's what I had:

• Enormous statue of a woman (possibly elven?) clutching something to her breast. Any attempt to interact with the statue causes a major image to appear, requesting the password (image speaks Celestial). Password is "Adora," and the statue will release a holy avenger (unabashed She-Ra fan)
• A permanent storm swirls over this section of the ocean, churning the waves. Lighting flashes in curious intervals. Observers who pass a DC 15 Int check can determine the pattern is a Fibonacci sequence (1 lightning bolt, then another, then 2 bolts, then 3, then 5, topping out at 55 bolts simultaneously before starting again 5 minutes later). Success on this check gives advantage to sail through the storm.
• Sahuagin outposts
• Crashed nautiloid (mind flayer vessel)
• Arcanophagic currents, a roaming hazard that affects those traveling underwater. The currents eat magic, including water breathing spells and potions. Coming into contact with one (and they're nearly invisible) causes a check to see if any spells or magic items are drained. [I used these to keep the players from resting outside the underwater dungeon]

[Flallen]

I tried doing this myself, but my reach exceeded my grasp.

My thoughts on hexcrawls are that they are heavily front-loaded in terms of prep, but once prepped and stocked, you can run them with a minimum of at-table prep or improv. They're really good that way. They also give you a solid mechanical structure for moving around the map, something which is missing in D&D currently. For an example, check out the Alexandrian's blog on this.

My tips are to keep the maps small, make sure content isn't self-deleting (like a lost triton you have to guide back to safety), and if there are lairs on the map, make sure the hexes around that lair have that monster on their random encounter tables (or the monster's tracks).

As far as ideas, here's what I had:

• Enormous statue of a woman (possibly elven?) clutching something to her breast. Any attempt to interact with the statue causes a major image to appear, requesting the password (image speaks Celestial). Password is "Adora," and the statue will release a holy avenger (unabashed She-Ra fan)
• A permanent storm swirls over this section of the ocean, churning the waves. Lighting flashes in curious intervals. Observers who pass a DC 15 Int check can determine the pattern is a Fibonacci sequence (1 lightning bolt, then another, then 2 bolts, then 3, then 5, topping out at 55 bolts simultaneously before starting again 5 minutes later). Success on this check gives advantage to sail through the storm.
• Sahuagin outposts
• Crashed nautiloid (mind flayer vessel)
• Arcanophagic currents, a roaming hazard that affects those traveling underwater. The currents eat magic, including water breathing spells and potions. Coming into contact with one (and they're nearly invisible) causes a check to see if any spells or magic items are drained. [I used these to keep the players from resting outside the underwater dungeon]

I like some of these and will be using them. The Nautiloid is a funny one since they're actually traumatized by mindflayers by this point and are (unknowingly) retrieving a sunken spelljammer vessel. XD

So far I'm keeping it to 11 Hex tiles that will be just off the coast of the Nelanther Isles. I was going to try to have separate notes for above and below the surface but I think that's too much work. Let's just hope they don't decide to swim to land any time soon.

I'm thinking about dropping a Sea Dragon (Tome of Beasts) in one of the extreme depth hexes and I have the Aboleth, but I don't know what other creatures would work as lair monsters. Maybe some ridiculous Kuo-Toa godling? I'm too far out to sea for a hydra, I think.

[Yora]

I wanted to run The Isle of Dread as a straight oldschool hexcrawl sandbox. But unexpectedly, the journey to get there took us 12 sessions, during which so much had already happened and the players got focused on pursuing the lure to the isle with focused determination, that we all agreed to forget about the whole hexcrawling thing and just continue directly with the quest that so much effort had already been put into.

I don't feel hexcrawl mechanics don't have much purpose when pursuing a specific goal. They become more of a nuisance and padding that keeps the players from dealing with the things they are actually interested in.

I think looking for a wreck requires a more specific plan than simply combing the entire ocean floor. The players need to follow clues about its position to narrow down the area. With visibility underwater being maybe a few meters at most and not having GPS data about the last known position, finding a wreck just by looking wouldn't work.
I would do it more like an investigation to follow clues and rumors to find some sea creature that accidentally saw the wreck and can tell the players how to get there.

[Dr paradox]

What size of hex were you picturing? Do you imagine that they'll be moving from hex to hex underwater, or will each hex be a distinct dive from the surface? Do you want every hex to be interesting, or will some of them be merely cosmetic?

[Flallen]

I wanted to run The Isle of Dread as a straight oldschool hexcrawl sandbox. But unexpectedly, the journey to get there took us 12 sessions, during which so much had already happened and the players got focused on pursuing the lure to the isle with focused determination, that we all agreed to forget about the whole hexcrawling thing and just continue directly with the quest that so much effort had already been put into.

I don't feel hexcrawl mechanics don't have much purpose when pursuing a specific goal. They become more of a nuisance and padding that keeps the players from dealing with the things they are actually interested in.

I think looking for a wreck requires a more specific plan than simply searching the ocean floor. They already have an idea of where they need to look, so they aren't running in and just searching wherever. The players need to follow clues about its position to narrow down the area. With visibility underwater being maybe a few meters at most and not having GPS data about the last known position, finding a wreck just by looking wouldn't work.
I would do it more like an investigation to follow clues and rumors to find some sea creature that accidentally saw the wreck and can tell the players how to get there.

I'll have to see how this works, but I don't think it is going to hinder them from engaging with things they want to engage with. The party has a sea elf and the other two are going to have access to swim speeds, so I'm not treating their vision as being a couple metres, they will get their full vision range assuming nothing obscures it.

What size of hex were you picturing? Do you imagine that they'll be moving from hex to hex underwater, or will each hex be a distinct dive from the surface? Do you want every hex to be interesting, or will some of them be merely cosmetic?

I hadn't really thought about having some hexes be decorative. So far I have 9 of the 11 Hexes being full of encounters which I think is going to end up being about 90 000 exp, which is plenty for a level 8 party. Is it usual to have hexes be just decorative? The hexes are 8 miles across and I'm thinking about keeping them to just about a dozen hexes for now since I don't want them to be overwhelmed with options.

If you have any ideas for interesting set pieces I would love that! I'm trying to come up with a shrine to Umberlee that would look really cool (and from which they can either steal Mariner's Armor or offer tithes and receive a blessing to help with water breathing).

There are three main things I have going on around the hunt for the shipwreck: a paranoid sea elf village where rumour of a Malenti are creating internal strife, a conflict between the sea elves and the sahaugin, and an Aboleth seeking to use its kuo-toa servants to expand its empire to include the sahaugin and sea elves. I'm thinking about having a Marid as well who has declared himself Saeadat il Malak Samak, Lord of all the Fishes in the Sea [the Arabic being roughly translated as His Excellency King Fish], but I don't really have a purpose for him yet... the initial idea was to have an unusual traveling salesman, but I don't have any ideas for what he would be selling or why someone as regal as himself would be doing the fin-work himself to begin with or what his ambitions should otherwise be. I don't want to go the route of "he wants slaves to do his bidding" because that would be grounds for a fight which the party wouldn't survive and would also ruin what seems like it could be a fun RP encounter.

[Dr paradox]

I hadn't really thought about having some hexes be decorative. So far I have 9 of the 11 Hexes being full of encounters which I think is going to end up being about 90 000 exp, which is plenty for a level 8 party. Is it usual to have hexes be just decorative? The hexes are 8 miles across and I'm thinking about keeping them to just about a dozen hexes for now since I don't want them to be overwhelmed with options.

If you have any ideas for interesting set pieces I would love that!

I'm running a hex crawl campaign myself, and I'm doing one mile hexes with a lot of non-combat hexes - minor ruins, monuments, notable natural and geographic features. It might be a benefit spacing out your combat hexes with some of those, so the ocean floor doesn't feel like a raging warzone. A few chances to absorb the somber beauty of that sunken, dark, and marvelous world might enhance the mood.

A few simple ideas.

1. A coral reef inhabited by a panoply of fish, all sparkling like gemstones beneath the water-dappled sunlight.

2. A sunken lifeboat that foundered in a storm last year. The bones of the two castaways are being swallowed up by the sea floor - one of them had plainly sustained a head wound, and the other had been caring for them. Possibly their ghosts speak, plaintively asking that they be put to rest on dry land, or maybe you just let the tableau speak for itself.

3. The bones of a whale rest on a sandy shelf overlooking an abyss. The leviathan's ribs, like the spars of an ivory ship, are now the playground for a colony of crabs.

4. A long trail of scattered marble statues along the sand mark the course of a ship holed below the waterline and obliged to dump its cargo. Bound for a king's new seaside palace, the statues were a series of masterworks, all the king's forebears. They now gravely reign over the groupers.

5. A battallion of luminous jellyfish blanket the floor and fill the water of this undersea valley. In the midst of them, a bronze diving bell is moored to the ocean floor - the abandoned underwater study of a scholar who was once fascinated with the creatures.

6. A great fissure in the Earth leads down into the darkness, where a small volcanic vent provides for an oasis of bizarre sea life.

7. A sparse forest of petrified trees, limbless and forlorn, is the silent hunting ground for a school of tiger sharks. Eons past, a volcanic eruption buried this forest in ash, and atom by atom the wood was replaced with stone. Geologic forces drowned the ashen plain, and the tires scraped away all but the hard stone of the trees. The sharks steer clear of the players unless commanded by sahuagin - they know the difference between predator and prey.

8. A broad underwater desert, scattered with rusted bronze tridents, helms, and spears. Here and there one can make out the footprint of an ancient vessel, long decayed. Centuries ago, Galleys and Triremes clashed on the surface. Thousands were butchered and the water was stained crimson from wave to seabed. Now, nobody remembers the names of the kingdoms that warred here.

9. An abandoned sea-elf temple is little more than an empty shell of itself, a pillared circular structure that shelters an anemone the size of an elephant, nestled in the foundations. It's harmless unless you really try to get killed by it.

10. Eighty foot towers of kelp strain toward the sun along the top of a ridge that just barely grazes the habitable zone. The surrounding lowland is dark, rocky, and barren, but up on the kelp island, barracuda and their prey eke out a living on blue shrimp.

There may or may not be treasures at any of these locations. The anemone and the diving bell would seem clear opportunities, but I'll leave that up to you. You could put non hostile locals like the sea elves in small traveling bands to give some social context, where appropriate: maybe the temple with the anemone is still a site of pilgrimage.

[Flallen]

I'm running a hex crawl campaign myself, and I'm doing one mile hexes with a lot of non-combat hexes - minor ruins, monuments, notable natural and geographic features. It might be a benefit spacing out your combat hexes with some of those, so the ocean floor doesn't feel like a raging warzone. A few chances to absorb the somber beauty of that sunken, dark, and marvelous world might enhance the mood.

A few simple ideas.

1. A coral reef inhabited by a panoply of fish, all sparkling like gemstones beneath the water-dappled sunlight.

2. A sunken lifeboat that foundered in a storm last year. The bones of the two castaways are being swallowed up by the sea floor - one of them had plainly sustained a head wound, and the other had been caring for them. Possibly their ghosts speak, plaintively asking that they be put to rest on dry land, or maybe you just let the tableau speak for itself.

3. The bones of a whale rest on a sandy shelf overlooking an abyss. The leviathan's ribs, like the spars of an ivory ship, are now the playground for a colony of crabs.

4. A long trail of scattered marble statues along the sand mark the course of a ship holed below the waterline and obliged to dump its cargo. Bound for a king's new seaside palace, the statues were a series of masterworks, all the king's forebears. They now gravely reign over the groupers.

5. A battallion of luminous jellyfish blanket the floor and fill the water of this undersea valley. In the midst of them, a bronze diving bell is moored to the ocean floor - the abandoned underwater study of a scholar who was once fascinated with the creatures.

6. A great fissure in the Earth leads down into the darkness, where a small volcanic vent provides for an oasis of bizarre sea life.

7. A sparse forest of petrified trees, limbless and forlorn, is the silent hunting ground for a school of tiger sharks. Eons past, a volcanic eruption buried this forest in ash, and atom by atom the wood was replaced with stone. Geologic forces drowned the ashen plain, and the tires scraped away all but the hard stone of the trees. The sharks steer clear of the players unless commanded by sahuagin - they know the difference between predator and prey.

8. A broad underwater desert, scattered with rusted bronze tridents, helms, and spears. Here and there one can make out the footprint of an ancient vessel, long decayed. Centuries ago, Galleys and Triremes clashed on the surface. Thousands were butchered and the water was stained crimson from wave to seabed. Now, nobody remembers the names of the kingdoms that warred here.

9. An abandoned sea-elf temple is little more than an empty shell of itself, a pillared circular structure that shelters an anemone the size of an elephant, nestled in the foundations. It's harmless unless you really try to get killed by it.

10. Eighty foot towers of kelp strain toward the sun along the top of a ridge that just barely grazes the habitable zone. The surrounding lowland is dark, rocky, and barren, but up on the kelp island, barracuda and their prey eke out a living on blue shrimp.

There may or may not be treasures at any of these locations. The anemone and the diving bell would seem clear opportunities, but I'll leave that up to you. You could put non hostile locals like the sea elves in small traveling bands to give some social context, where appropriate: maybe the temple with the anemone is still a site of pilgrimage.

This is really helpful, thank you! I had planned on doing non-hostile locals in the town, but you are right that there should be some other ones around the area too. I'll try to thin out my hexes to be a little less combat intensive.

Do you think I should reduce the size of the hexes to a smaller scale and have more of them?

[Dr paradox]

This is really helpful, thank you! I had planned on doing non-hostile locals in the town, but you are right that there should be some other ones around the area too. I'll try to thin out my hexes to be a little less combat intensive.

Do you think I should reduce the size of the hexes to a smaller scale and have more of them?

Ah, it really depends on how you're handling travel and the experience you want. I use one mile hexes because I put a big emphasis on different terrain types, travel times, and random encounters. It's perfectly reasonable to take a slightly more modular approach, where each hex is half a day of travel. This is particularly true if you don't want to have specific rules for travel paces on different terrain types, which is only really useful with random encounter tables.

I think eight mile hexes are fine in your case. One thing I do that could be useful for spicing things up is Monster Lairs: figure some distinctive monsters, place their lairs, and designate their hunting grounds. Whenever they're enter a hex in the hunting ground, you can roll a check to see if this monster finds them, which could add some combat to an otherwise peaceful location, or turn a pre-existing combat into a three-way battle. Picture Giant Squid, Sea Serpents, Jaws, Sharktopus, whatever you're feeling. Maybe only one or two monsters like that, if you decide it's a good idea.

[Segev]

Not besmirching any of the scale choices suggested here, nor necessarily recommending this, but Chult, in Tomb of Annihilation, is a massive hex crawl with 10-mile-long hexes, each being roughly a day's travel on foot by the rules that module sets out. The random encounter rules are one of the things I think weakest about it, encouraging nova-ing because you get, on average, less than one encounter per day, and many of them are non-combat, so even if you have multiple encounters, you can safely nova on one of them. And you WILL take a short rest after each encounter; there's no reason not to. It has some great sites, but unfortunately paltry reason to go to many of them. (Yellyark is random as heck to go to, and yet is key to getting the most out of another encounter you only have slightly more guidance to point you to.)

The Alexandrian's advice about having a SET encounter in every hex makes it a lot more prep work, but also makes for more interesting travel. Having more of those be sites-of-interest will icnrease true encoutner rate, too, to something more approaching D&D's expected values.

Ideally, you would have lots of "slow days" with nothing interesting that you can gloss through, and then a busy day that meets the usual D&D expectations for encounter rate. Chult, as written, doesn't really support that well. I tried to alter that by rolling up their expected encounters based on their planned route, and then moving them around a bit and making something of a narrative out of them, so some days would have 3-4 encounters that were embellishments on earlier or later signs and portents that were randomly rolled.

[Yora]

I think with random encounters in the wilderness, their purpose is really to meet new interesting people. You can have significant battles with wilderness encounters, but those would be against particularly dangerous opponents. Which in many cases wouldn't have their treasures with them and you'd still have to find their lairs to actually gain something from it.

[Flallen]

Not besmirching any of the scale choices suggested here, nor necessarily recommending this, but Chult, in Tomb of Annihilation, is a massive hex crawl with 10-mile-long hexes, each being roughly a day's travel on foot by the rules that module sets out. The random encounter rules are one of the things I think weakest about it, encouraging nova-ing because you get, on average, less than one encounter per day, and many of them are non-combat, so even if you have multiple encounters, you can safely nova on one of them. And you WILL take a short rest after each encounter; there's no reason not to. It has some great sites, but unfortunately paltry reason to go to many of them. (Yellyark is random as heck to go to, and yet is key to getting the most out of another encounter you only have slightly more guidance to point you to.)

The Alexandrian's advice about having a SET encounter in every hex makes it a lot more prep work, but also makes for more interesting travel. Having more of those be sites-of-interest will icnrease true encoutner rate, too, to something more approaching D&D's expected values.

Ideally, you would have lots of "slow days" with nothing interesting that you can gloss through, and then a busy day that meets the usual D&D expectations for encounter rate. Chult, as written, doesn't really support that well. I tried to alter that by rolling up their expected encounters based on their planned route, and then moving them around a bit and making something of a narrative out of them, so some days would have 3-4 encounters that were embellishments on earlier or later signs and portents that were randomly rolled.

I've got them on a gritty realism rest cycle where they can get back 1/4 max HD (2) per short rest and have access to Healing Surge as a combat action. It's been effective so far, but I'm trying to pay careful attention to this since gritty realism was initially the "in town" rule. Each hex has pre-determined encounters that are approximate to the 18000 adjusted exp per day they should get (this is assuming I go back to normal rest rules). I don't expect they will actually fight all of these necessarily, and I'm now rethinking this a bit based on what Dr. Paradox said about turning the ocean floor into a raging battleground. I might leave a few really hostile hexes and thin out the rest to function on the slower rest cycle.

[Sparky McDibben]

The random encounter rules are one of the things I think weakest about it, encouraging nova-ing because you get, on average, less than one encounter per day, and many of them are non-combat, so even if you have multiple encounters, you can safely nova on one of them.

Agreed, because hit points and spell slots are the wrong resources to target on a hexcrawl (which the designers ought to have made more clear).

Hexcrawls are simulated movement from point to point - that's all they are. They're supposed to simulate what happens if you get lost, what you can run into, etc. They're a game structure for wilderness travel. In other words, they aren't a dungeoncrawl, so let's stop taxing the same resources. What we should be taxing is how long the players can survive in that environment. If they can only stay in the wilds outside the dungeon for a few days (because that's all the food and water they can carry), they'll think very carefully about 5 minute adventuring days inside the dungeon. This feeds into the dungeoncrawl as well.

Let's suppose you've got a 5th level cleric who can cast create food and water, or a 5th level ranger with access to multiple goodberries. Those don't solve wilderness travel - they simply mean your caster is down a spell slot (particularly significant in the cleric's case, since that's one less spirit guardians they can cast) when they go into the dungeon. In short, the wilderness travel is already starting your PCs off at sub-optimal resources, meaning some of the work of attriting the resources is already done for you.

What this means is that even if you have a party with multiple mid-level casters, you can use the environment against them. Include weather events like thunderstorms or blizzards that reduce visibility and risk the PCs contracting disease through prolonged exposure. The longer they stay in one spot outside the dungeon increase the probability of random encounters overnight. Adjust your tables to let the dungeon denizens reach out and attack the PCs.

This puts time pressure on the PCs. Their resources are running out, they can't afford another long rest. Ergo, the resources you should be hitting PCs with on the hexcrawl are the threat of spoiling (or stealing) rations, hitting PCs with levels of exhaustion, draining Hit Dice, degrading their equipment, etc. Basically, anything that doesn't reset on a long rest. You want the party to feel pressured, threatened, and unsafe. Thus danger, thus stakes, thus adventure.

Also, this model makes escort missions a lot more fun as a DM, because the "cargo" (refugees, couriers, lost princes, etc) become a resource you can target.

(For anyone who brings up the Outlander background or the Ranger's Natural Explorer feature, just homebrew the background to restrict where it works, like only in the area the PC grew up in, and let the Ranger enjoy being an awesome wilderness guide).

[Segev]

In my case, letting the ranger be an awesome wilderness guide was part of what diminished the alternate resources game. That and I probably was too generous letting them forage for food, but honestly, the foraging rules are pretty generous in and of themselves.

[Sparky McDibben]

In my case, letting the ranger be an awesome wilderness guide was part of what diminished the alternate resources game. That and I probably was too generous letting them forage for food, but honestly, the foraging rules are pretty generous in and of themselves.

The ranger's poor implementation in 5e is why I'm OK highlighting how hard the wilderness is...and then letting the ranger solve several of those problems.

I get around the foraging rules by either allowing (a) one character to forage during the day, or (b) up to half the characters to forage for an hour after they halt.

The first case limits how much food and water the party can acquire.

The second case imposes a risk because I also make random encounter checks during that time for each character. Any encounter check that leads to combat (I vary encounters by starting distance, attitude, and whether either party surprises the other) automatically nullifies their foraging result. I usually narrate something like: "As you close in on the magnificent buck you've been stalking the last forty-five minutes, you take aim with your bow. A slight breeze tickles your cheek. A dead silence falls over the forest. The fletching reaches your ear...as a smell like wet dog reaches your nose. Trusting your instincts, you narrowly avoid being disemboweled by the eight foot tall werewolf that leaps out at you from cover! As you look back, the prize buck has fled, but the werewolf bares its fangs at you in a hideous snarl. Take 18 points of slashing damage and roll initiative, please."

[Flallen]

So far, this is going well! They found some of the more peaceful hexes first (by chance), so I've gotten to marvel them and creep them out. Now I just need a fitting curse for someone who stole from a shrine to Umberlee. I'm thinking about having it be that all animals are hostile to them, which will make traveling the sea a little less peaceful.

Thank you to everyone who chimed in!

[Segev]

So far, this is going well! They found some of the more peaceful hexes first (by chance), so I've gotten to marvel them and creep them out. Now I just need a fitting curse for someone who stole from a shrine to Umberlee. I'm thinking about having it be that all animals are hostile to them, which will make traveling the sea a little less peaceful.

Thank you to everyone who chimed in!

Umberlee? Isn't she the drowning goddess? The one who likes drowning everyone?

If she's not going to give them the Aboleth curse of being able to breathe water but not air, have them always exhale seawater. They can breathe...but they're always exhaling water, making it hard to talk and making them FEEL like they're always about to drown.

[Flallen]

Umberlee? Isn't she the drowning goddess? The one who likes drowning everyone?

If she's not going to give them the Aboleth curse of being able to breathe water but not air, have them always exhale seawater. They can breathe...but they're always exhaling water, making it hard to talk and making them FEEL like they're always about to drown.

That is excellent. This is excruciating enough without being too punishing. I'll probably have it last either two tendays or a month which will force them to actually explore the aquatic area for longer than they had intended and put some pressure on their deep gnome's hesitance to swim.

[deljzc]

I think the new Ghosts of Saltmarsh does one of the adventure steps as a ship wreck. And there is a stop at a tropical type island with tons of undead as well.

Since most campaigns have some degree of exotic trade to tropical, dangerous areas, it seems plausible to have to find a bunch of "clues" leading to where the ship wreck happened or using the ship wreck as a clue towards finding a lost captain or finding some important artifact or treasure.

[Dr paradox]

Keep us posted on your findings! I'm very interested.