My rover needs an electric trolling motor.

[keoki]

I'm in career mode, and I'm realizing that to explore the worlds with liquid on them, it might be nice to have an electric outboard motor that I can run off of solar power to get around. Spinning rover wheels in the water seems to have no effect, in fact the oceans have no current, it seems. I can turn, and splash, but no directional movement seems possible. Has anyone figured an electric form of liquid surface propulsion? I know I could use jets or rockets, but that isn't what I'm looking for.

Edited November 16, 2013 by keoki

[Traches]

The only ways I can think of to do it stock would either be exceedingly difficult or exceedingly slow, but the firespitter mod has some electric propellers you could try. You could make an airboat? I'm not sure what would happen if you put one in the water.

[Kasuha]

You could try a plane. On Laythe you can use jet engines. On Eve, you need rocket engine or Kethane engine from the Kethane mod.

[Jason Patterson]

It's fuel driven engines or mods, unfortunately. You could probably bodge together something crazy that uses the torque from a disconnected command module with fins, sort of a command module-propeller combo, but that kind of thing is going to be a curiosity rather than a practical ssolution.

[boomerdog2000]

Ion engine might work. Be pretty slow though. Of course if you're travelling by water that doesn't seem to matter, since it takes forever to go anywhere on the surface anyway.

[ultrasquid]

Boating is certainly possible, but the dynamics are not well optimized. Travel over "water" is invariably noisy and splashy. Some work will have to be done in the game engine to improve that, and I don't think it's a priority at this stage of development. The Firespitter mod (mentioned above) provides many of the things you'll need, though, including electric propellers, floatation pontoons, and high-capacity batteries.

[keoki]

Yeah, where there is water, there is air, so flying is a good option... Fuel is the main issue. Electric power helps keep things light. Honestly this came up because I ran out of fuel trying to de-orbit onto a small island for a landing, and it occurred to me that it would be nice to be able to recover by boating to land. We have rover autopilots now, so throw open some solar panels, and set a course, and go do other things while the rover-boat trolls along.

As for the pesky ion engine, I would love to make use of that for something, but until we can warp while throttled up, I'm not sure what good the ion engine is for game play. Hopefully we can have some autonomous deep space probes to explore other star systems in a future version of the game.

[boomerdog2000]

You can physics warp with it on, but in the water that would probably be even hairier than in space or atmo.

[Geschosskopf]

In stock games, the only way to do boats that move at all is to power them with regular rocket or jet engines, and these have to be mounted on hulls where the fuel tanks don't touch the water. Either build a comlete hull out of structural panels or use just a few panels steeply angled upwards on the ends of I-beams as hydrofoil fins. If fuel tanks stay in the water, you'll never move more than your own length before running out of fuel. Check out the challenge about building the fastest boat for ideas.

So that will get your stock boat moving and speeds up several hundred m/s are possible. HOWEVER, there's still the problem of maneuvering. Above about 10m/s no amount of rudders above and/or below the waterline will have any effect. So what you have to do is move in straight runs, stop the engines, wait until you slow down to less than 10m/s, then pivot to the new heading and fire up the engines again. Maybe RCS would work better but I haven't tried that. Also note that apart from retrorockets (which I don't recommend on hydrofoils) there's no way to brake, you just have to coast to a stop, which can take a long time.

With mods, you have several options. Probably the easiest is Firespitter, which has pontoons. While intended for seaplanes, they make for great boats if you saw the wings and tail off the seaplane. With these, you still need a conventional engine in the fuselage. Maximum speed is about 120m/s, beyond which the pontoons explode. However, the pontoons have special rudders built into their rear ends that allow full control even while moving fast.

There's also the Boat Parts and Sub Parts mods by Infinite Dice, which makes excellent boats. Problem is, none of these were intended for space, just staying on Kerbin. Thus, they're very dificult to attach to rockets to take elsewhere. Also be advised that these mods make substantial changes to how water behaves, which might impact anything else you have in the water, although it probably won't. Just keep that in mind.

Then there's Hooligan Labs' submarine mod. Last I looked at this, it only provides a means of getting underwater; control systems and propulsion are up to you. As seen in Scot Manley's "Eve or Bust" videos, you can use B9's compressed air RCS system with a user-modified air intake to do both of these tasks, although you won't move very fast. Also note that with Hooligan subs (unlike Infinite Dice subs), the buoyancy of everything in the game is changed. The Hooligan sub parts actually don't make you sink, they make you float. Without these parts, EVERYTHING (including Kerbals) sinks like a stone and going below 600m causes instant death.

[keoki]

Everything sinks? No, everything floats. Kerbals float, and they can swim. My all metal rover floats. No buoyancy mods here...

Driving into a shallow puddle will get the rover stuck, I have to get out and swim my kerbal behind it to push it till the wheels touch bottom, about a meter deep. In the ocean, that would take months to get to shore. In a shallow sea, if I could sink, I could probably drive to shore on the bottom. Don't need to build a boat, just need an outboard motor.

Edited December 12, 2013 by keoki

[Geschosskopf]

Everything sinks? No, everything floats. Kerbals float, and they can swim. My all metal rover floats. No buoyancy mods here...

Yeah, that's normal. I was saying that one of the effects of the Hooligan submarine mod is to make everything sink.

Driving into a shallow puddle will get the rover stuck, I have to get out and swim my kerbal behind it to push it till the wheels touch bottom, about a meter deep. In the ocean, that would take months to get to shore. In a shallow sea, if I could sink, I could probably drive to shore on the bottom. Don't need to build a boat, just need an outboard motor.

Well, AFAIK there are no outboard motors. Boats are not something that's gotten much love either from Squad or modders.

As suggested above, you MIGHT be able to use one of the Firespitter electric airplane propellers but be warned those are both heavy AND require scads of electricity so are probably impractical for a small rover. And besides, there's still the issue of trying to push something through the liquid, which ain't easy unless you have mod parts specially designed for that.

The closest thing I can think of to an outboard, as in small, light, and not taking much juice, would be to make paddlewheels using Magic Smoke Infernal Robotics parts. This WILL move you along but VERY slowly.

[Kasuha]

As long as that thing in the picture below can run on water, you could probably make the ring a bit wider and run a rover inside like a hamster in hamster wheel.