***This post contains spoilers for Tomb of Annihilation***

So my crew of adventurers have been buying supplies in Port Nyanzaru. I wrote some shops myself for more jungle type shops, including a sort of tinkerers shop that sells expert survival gear for Chult.

One of my players asked if the shopkeeper had a compass for sale and I reasoned that he would for a decent sum of money. It is an official tool of a cartographer's kit so it seemed fine. Only after they bought it did I realize that getting lost in the Chult jungles is quite critical to the story of the whole adventure. Since last game I have been thinking about how I could make it so that the compass does not mean they hardly ever get lost. I mean I really appreciate their effort to think of buying one so I do not want to make the compass useless, just not too good. I haven't really thought of a good way to deal with it yet.

The jungle might have impassable terrain or overcast skies which would make it harder to navigate normally, but with a compass one would always know if they are going the wrong direction, right? How should I play this?

Thanks in advance for any suggestions.

A compass lets you know what direction you’re going, it doesn’t tell you where you are. You can have a compass and still not know where the hells you are. What happens if you travel too far, or don’t travel far enough? With a compass, you’ll be able to make the right turns, but you still might make them at the wrong places.

The DMG gives players advantage on navigation if they can see the stars, as that way they’d be able to tell which direction is which. That’s the same thing a compass does. So, I’d give them advantage on their checks, but nothing more.

I'd also add that when I played ToA the DM only had us roll a few times for getting lost.

We had decent guides and honestly, getting lost doesn't really do much to the narrative and gets either frustrating or boring very quickly. Traveling in the jungle is slow and painful anyway. Combine that with the weather (some days you can't travel due to torrential rain), random encounters (undead, dinosaurs and other jungle life), general lack of content in the jungle and eventually both the players and the DM can't be bothered wasting anymore time with yet another random encounter in the jungle and an extra day used up just because someone failed a survival check. The players are operating under a quest clock due to the death curse on the sponsor of the trip. Travel through the jungle in Chult is slow ... 1 hex/day ... possibly 2 on a river.

This means that you are looking a minimum of about 30 days to Omu if you go direct and don't do any side quests. The party has a time limit on the order of 80 days. A time limit that isn't much fun and the players don't actually know exactly how long it is.

The bottom line is ... I wouldn't worry about the compass ... give them advantage on survival checks for direction.

I don't know about ToA, but I do know about compasses.

A large piece of ferrous metal (iron or steel) will throw a compass off.  If there is a dead adventurer in plate or chain nearby, just under the surface, that would be an example of throwing off the compass.  Likewise, if any PC is wearing metal armor or even carrying a ferrous metal weapon larger than an arrowhead, the presence of the metal will throw off the compass.

In the army I had to remove my helmet and place my weapon below my knees when standing to get a confident read on my compass.  But that was a long time before GPS.

I would also rule that magic sometimes affects compasses, particularly any Lightning Magic.   

Thanks all for the suggestion, I will incorporate this!

On a more specific note, how would I deal with rolling the D6 to determine in which direction they get lost, when they do? It feels weird to have them backtrack to a previous hex if they decided to move forward and have a compass to check they are going more or less where they want to go. I.e. how would I explain them they accidentally did a full 180? I was already maybe thinking of rendering the compass useless due to a sudden sheer cliff or giant river filled with crocodiles.

Quote from MusicScout >>

I don't know about ToA, but I do know about compasses.

A large piece of ferrous metal (iron or steel) will throw a compass off.  If there is a dead adventurer in plate or chain nearby, just under the surface, that would be an example of throwing off the compass.  Likewise, if any PC is wearing metal armor or even carrying a ferrous metal weapon larger than an arrowhead, the presence of the metal will throw off the compass.

In the army I had to remove my helmet and place my weapon below my knees when standing to get a confident read on my compass.  But that was a long time before GPS.

 that is so cool!

You could have their guide mislead them on purpose. Following the guide it is possible the PCs will not even look at their compass. Even if they do, the guide could tell them something like, "You going to trust that little bit of wood and metal, or somebody like me who has lived here all his life?"

> Give advantage on checks or give a bonus of some sort (expertise in survival when using it or something).

> If they get lost they can't get quite as lost. If they're heading South, they might end up SE or SW for example. That would be easily achievable by navigating around an obstacle or something.

Getting lost is not a vital part of this campaign. It adds nothing to the actual story, and it can potentially make an already VERY long journey even longer and more frustrating. Your players have put in the gold to help avoid it, so play along with them rather than thinking you have to be the "antagonist". FWIW there are other ways to make the getting lost part trivial, including a prodigy feat/rogue/bard investing expertise bonuses into survival, having a ranger with the correct preferred terrain. Even picking some of the guides can make life easy since some of them have ~+7 to survival.

IMO don't try to nerf this compass in anyway unless your party have specifically said they're looking forward to a long hex crawl.

Quote from Tecnik >>

Thanks all for the suggestion, I will incorporate this!

On a more specific note, how would I deal with rolling the D6 to determine in which direction they get lost, when they do? It feels weird to have them backtrack to a previous hex if they decided to move forward and have a compass to check they are going more or less where they want to go. I.e. how would I explain them they accidentally did a full 180? I was already maybe thinking of rendering the compass useless due to a sudden sheer cliff or giant river filled with crocodiles.

 Just because hexes are being filled in on a map doesn't mean they are correct.  Let them keep going forward (in their eyes) and you just keep their true position.  When there is questions about landmarks being in multiple places or that mountain looked like the last one, let them figure it out.  The best thing is to never tell them where they truly are until they enter something that is important.  In the end, the map isn't the important tool (nor the compass)... the progression of the story is the important tool and you are the only one that can use it.

Like SwiftSign said. They get a little lost. Instead a d6 just do odd they left of the hex they want. Even they right of the hex they want.