I'm current;y writing an entire shadowrun team that mostly takes missions involving the water (Aquacologies, piracy, etc....) that I'm going to give my group as pre-gen characters so I can run a short campaign using the underwater rules.

I want one of the team to be a rigger so I've used the vehicle design rules in Rigger 3 to create some Sea Sled chassis drones and some Hovercraft chassis drones for him to use. My question is...... do radio signals travel as well underwater as they do in the air? If they don't (which i suspect may be the case), do they travel at all, in which case a reduction in the rating of the RCD for Flux range purposes would be required. Or would the rigger need to use some other method of transmitting order (like a long cable).

Any real world physics knowledge and rule suggestions would be appreciated. If it is too unrealistic I may just throw reality out and have him rig like it's abbove water.

If anyone's interested, the rest of the team is going to be a Shaman (some water type animal totem), a cyberred guy with cybergills, internal air tank, cyber fins, electronics skills and shooting/fighting skills and a SURGEd adept (with underwater SURGE effects, may have to make up a couple) for fighting/swimming power.

No, you can't rig underwater by radio waves. There is a page in R3R (No book access ATM) that specifies all underwater drones/remote control is done by lengths of fiberoptic cable. Theres also some rules regarding the cable getting cut due to bad maneuvering/taking fire. Good standing order for those drones is, if communication lost, return to main boat.

I'll try to dig out the page sometime, provided I remember. Don't forget, sea sled chassis can pull along divers as well, speeding up their movement underwater and actually making them effective.

Another note, gyrojet pistols, spear guns, and the water carbine are the only 3 underwater designed weapons that come to mind. You might want to play a bit with cannon companion to make something else should you want it.

IIRC, the part of the electromagnetic spectrum that best penetrates water is visible light; and even then it's not very good. A laser link would have the best penetration, but would be blocked by a stray fish. Basically, there's no good way to communicate underwater. And of course, the ultra-low frequencies that they use to communicate with submarines could never manage the bandwidth for simsense. Basic instructions at best, and even then very slowly.
Everything needs to be on a cable or autonomous.

As a technical question, could one use sound waves to carry high bandwidth data?

Define "high bandwidth"? Over short distances it can carry at least 300 baud.

Being a stickler for terms, the answer is yes, as you can modulate a tone from 20 to 20,000 hertz, a pretty wide frequency band approaching the size of the 802.11b/g channels.

~J

well, when i had a 300 bps modem, 33.6 kbps would have been defined as "high bandwidth", but in no way, shape, or form would i consider it "high bandwidth" now - i would consider it extremely hobbled and "low" bandwidth...

...it would certainly not be enough for simsense data...simple comms (voice only), data, yes, but that's about it...

learn to speak "whale" (or would that be orcish??)...

But would it be enough to send "simple" commands to a drone brain?

Thanks, I'll have to go look for those rules about the fibreoptics.

Define "simple" this time

~J

The kind a drone brain can understand? Is that just vocie command level or simsense level? I don't know enough about the rigger rules to say.

Sound waves??

yeah, you could try, but interference would be killer, and effectiveness would be lost once you moved at any decent speed.
stick with fibreoptic wires.

How is the resolution on sonar? Presumably, if you could build an arbitrary sonar image, you could transmit as much information as the usual sonar image…

~J

AN/WQC-2A Sonar Communication Set

You're saying Sonar doesn't work over 20 knots?

...and it doesn't work reliably through thermoclines, ect...

Subs are like a big game of hide and seek.

That's cool, but it doesn't make fiberoptics much better of a communication feature unless you need to rig the drone directly. And then there is sationary underwater platforms and mining drones. Of course, you could have induction grids in those cases, similar to GridGuide.

My suggestion?

If he isn't paying for them himself, give the drones a solid sensor array(Rating 4+), a rating 3 pilot, a rating 3 gunnery chip, and some pre-set orders that you activate with morse code or one-word orders. Maybe "STRANGELOVE" triggers the "KILL KILL KILL" order, "DUNKLE" triggers the "RUN RUN RUN" order, etc. Other than that, they should be able to handle themselves fairly well underwater as long as you heavily armor them. There seriously isn't much that can handle sustained firepower from a drone.

Addendum to the underwater weapons listed above - There's a few underwater weapons listed in the Rigger 3 weapons stuff. Don't forget the ink grenades and such - Squid-fu yo.

Almost off-topic, but not quite - I just had an idea. Have some high-speed high-strength drones whose only purpose is to grab hold of other drones or people in order to make it easier for their teams drones to rip them to shreds.

plus, there's the kinky anime factor. "oh noes! the SS Virgin Panties is enwrapped in horrible, squirming tentacles!"

Ok, I'm having some trouble. Can anyone give me some help for making the underwater drones? I was going off a base of a Medium Sea Sled Chassis with a Large Electric Fuel Cell Power Plant. I had intended to give it a torpedo tube or two but when I'd done most of the work I discovered that for the autoloader equipment it would need it is over 50,000kg which only a nuclear power plant can really support (is this an errata? it's not listed on shadowrunrpg.com as one.). Maybe the sea sleds should just be for transport and rely on torpedos dropped from hovercraft/boat/air drones for anti seacraft offense, but they'd still need an autoloader?

What weapons is it possible to give an unmanned drone? I couldn't find those tentacle things somebody mentioned, could you give me a page reference?

I did find the reference to the fibreoptic cables though it didn't say how much it costs for how long a cable, any guesses? The torpedo probe comes with a 15km cable so I guess it's not too expensive and I wouldn't expect they'll ever want longer than that.

Underwater drones should be able to mount Gyrojet pitols and rifles on hardpoints or firmpoints (or turrets really). I'd think a spear gun (CC pg31) could be mounted on a sub or a harpoon gun (R3 page 88). What about just loading torpedos on missile racks? Do rail guns work underwater?

Target Wastelands page 131 has the Ares Snake-Spine Blade Arm, but you can also find them under vehicles in the NSRCG.

Fibreoptic cable is covered in Matrix. ¥1 per meter.

~J