The Brass Koi (Patreon)

When I first started drawing this map, I was trying to avoid making it look too modern, since most people are probably going to use it in a fantasy setting. Then I saw a picture of a fighter jet and I thought about how cool a canopy like that would look on a submarine, so I drew one in. I still think it's within the realm of "something a gnomish inventor might build," but I apologize if I went too far. You've gotta admit, though-- that canopy is pretty sweet.

I'm giving out the annotated version of the map to everyone so I can explain the various parts of the sub, since not everyone knows how a submarine works. Let's start with the ballast tanks (5). In order to make the sub dive, you have to make it heavier. You do this by opening the ballast tanks to fill them with water. To ascend, you force the water out with air tanks and pumps (6, 11). This is how you control the depth of the submarine.

If your party has a submarine, they probably need to be able to get out of it underwater. That's what the lockout chamber (16) is for. You enter from the top, seal it shut, then open the door to the outside. The lockout fills with water, but the rest of the sub doesn't.

And then there's the light (3). Gnomish inventors probably aren't building you a sonar system, so you're piloting this thing the old-fashioned way. And since it's dark underwater, you need a lamp. The Koi has a lamp and reflector in the bow so you can avoid crashing into rocks or running over any passing kuo-toa. Or maybe you want to splatter the kuo-toa. It's up to you, but you need to be able to see them either way.

I hope that helps everyone understand the map a little better. As I said before, I'm going to make a spelljammer version of this map as well. You know, the more I think about it, the more I like the idea of an amphibious spelljammer. Anyway, I'll have that for you tomorrow. Until then!