Hello again! We've been back and forth on how engines and fuel work, and this is the latest refinement. We're interested in what you think.

The basics! Ships carry Fuel. Running the engine or switching the lights on uses up Fuel. Run out of Fuel, and you're adrift in the dark. That won't end well. Fuel takes up cargo space, so you can go longer distances but then carry less other stuff.

A problem! Something we realised quickly in playtesting. It's hard to decide what the top of the fuel gauge means, if we don't have a dedicated fuel tank. If we have 100 units cargo space, then is the gauge 'full' at 10 units, or 20, or 50? And what happens if you swap ships and get 200 units? Either we have an arbitrary top end, or the top end is always ALL YOUR CARGO space in which case the gauge is usually half-empty even when you have loads of fuel.

Another problem! Either the ticks in which fuel is used up are quite far apart - which leads to weird and exploity behaviour - or fuel is used up every second - in which case either we have to track half-used barrels, or fuel gets used so quickly that it takes up all your space.

We could just have got round this by having a dedicated fuel tank - but we really like the idea of fuel being cargo. It ties into some story and it allows people to make hard decisions about what they can afford to take across the zee.

Our solution! When you undock, your stokers will load a unit of fuel into the engine (you can't leave dock without at least one). Your boiler starts warming up: as it does, your maximum speed and light radius increases. Pretty soon it'll be toasty, and you'll be up to cruising speed. The fuel gauge shows the fuel currently in your engine, being used up incrementally, and we also show a merry flame icon to indicate that your boiler's warm. When the fuel in your firebox is used up, your stokers load another unit of fuel in, and you get a low-key notification about that. You can see the amount of firebox fuel at a glance, and flip to cargo view to see how much you have in your hold.

If the fuel in your engine runs low and you don't have anything in your cargo hold, you get a warning. If the engine runs out of fuel and you don't have any more, the boiler temperature starts dropping rapidly... and your max speed and light drops with it. You have a narrow window of grace to get somewhere you can refuel, but you're beginning to coast, and the light is dwindling. Grim!

We think this makes the ship feel a little more like a steam-driven vehicle, as well as rationalising some of the resource decisions nicely.

A further refinement! We like the idea that you could instruct your stokers (with a mouse-click) to load extra fuel into the boiler, increasing the temperature beyond normal, before you run out of fuel. This would really burn through your fuel, but mean the engines would run faster than usual. It'd take some fiddling to get right, and we'll test it, but we wondered how you feel about that extra bump of complexity. If you're choosing a course, wondering which port to trade at, steering round enemy ships and watching your secrets tick up, do you also want to be working on how to keep your engines at max speed? Does that feel like an extra fun wrinkle, or a little too much? There are hybrid solutions, of course, where we could set the boiler preferred temperature or something - but we could just leave that complexity out.

Let us know your reactions!