Can railgun fire underwater?

[slade2501]

I never thought about it till this campaign, where the PCs are doing a lot of river crossings with power armor and giant robots. if they get attacked under water, do railguns fire as normal? or are they inopperable or reduced range/accuracy?

[ShadowLogan]

Per RAW in WB7 there are x7 examples of Rail Guns that fire at reduced range underwater (Triax and Kittani designs, plus a few of the Orca "Power Armor"), we also see at x1 example in SB4 (Sea SAMAS, though the naval version of the CS spider-skull walker doesn't include adjustments, possible oversight?).

So, to answer your question, yes rail guns can fire underwater (w/n the RPG rules) but do so at reduced range. There is also indication that those cited examples are not strictly purpose built since the RUE Glitterboy writeup includes notes about firing the Boomgun underwater (but like the CS Spider-Skull Walker in SB4 does not list any range modifiers as found elsewhere). Now most likely the GB and CS-SSW RGs (and all other RGs) do suffer range penalties underwater even if it isn't listed (I thought there was a generic modifier section for weapon systems when firing underwater like in 1E RT for Rifts, but I don't know where it is off hand and I did not see it in WB7/SB4).

[WesleySnacks]

Per RAW in WB7 there are x7 examples of Rail Guns that fire at reduced range underwater (Triax and Kittani designs, plus a few of the Orca "Power Armor"), we also see at x1 example in SB4 (Sea SAMAS, though the naval version of the CS spider-skull walker doesn't include adjustments, possible oversight?).

The entry for the Beachmaster in Northern Gun 1 mentions that the variant with the Heavy Rail Cannon cannot fire the cannon underwater, suggesting railguns do have to be built for underwater purposes.
Or someone forgot that it was previously established that they can fire underwater.

[slade2501]

awesome answer, thank you. In my campaign, the Minion war is over and Triax is selling more "older" (read book 1) equipment in tHe US, including the X-622 Kaefer or Bug. Its got the "Man-killer" as its primary forward facing weapon, and the players love its water capabilities (it fears no river or lake). But they were worried about firing it underwater, understandably.

[glitterboy2098]

Per RAW in WB7 there are x7 examples of Rail Guns that fire at reduced range underwater (Triax and Kittani designs, plus a few of the Orca "Power Armor"), we also see at x1 example in SB4 (Sea SAMAS, though the naval version of the CS spider-skull walker doesn't include adjustments, possible oversight?).

Wb7 also says that you can make railguns work properly under water using special ammo shapes. Presumably this requires special barrels and such.

[taalismn]

Supercavitating ammunition is my answer to making more efficient underwater rail guns.
But also pay more attention to cleaning them between immersions, to clean out salt/crud build-up.

[slade2501]

no mega damage brass alloy on rifts earth, gotta scrub all the metal regularly to prevent fouling for sure.

[ShadowLogan]

Per RAW in WB7 there are x7 examples of Rail Guns that fire at reduced range underwater (Triax and Kittani designs, plus a few of the Orca "Power Armor"), we also see at x1 example in SB4 (Sea SAMAS, though the naval version of the CS spider-skull walker doesn't include adjustments, possible oversight?).

Wb7 also says that you can make railguns work properly under water using special ammo shapes. Presumably this requires special barrels and such.

Citation please. The only place I found any mention in WB7 is with the Kittani Underwater Railgun (pg173) that stats "A rail gun that is designed to operate at maximum efficiency underwater. The rounds are either tiny metal balls or needle-like spikes." The shapes listed here are of course more restrictive than normal list (from RMB) and this example does get better UW/Air Range ratio than other RGs in WB7 (about 10% more range underwater).

I can get behind the special ammo shapes contributing to improved performance if the new rounds seek to minimize drag while moving through the water.

[glitterboy2098]

looks like you are right. that's what i get for relying on memory. i probably generalized that in my own games (since IRL there have been a lot of research into such things, from russian underwater assault rifles to the US navy researching CIWS ammo they can use to intercept torpedoes)

i will say that WB 32 Lemuria seems to have the definitive for this sort of question.. pages 59-60 has rules for underwater combat, including how it effects weaponry. it lists railguns as being 50% range reduction.

[ShadowLogan]

i will say that WB 32 Lemuria seems to have the definitive for this sort of question.. pages 59-60 has rules for underwater combat, including how it effects weaponry. it lists railguns as being 50% range reduction.

which is actually BETTER than the stats presented in WB7/SB4 for underwater vs air range for almost all of the previous mentioned railguns (though I do agree 50% reduction is simpler and easier to implement) for these weapons which are presumably designed for UW operations.

Spoiler:

Listing Examples:
Kittani Underwater Railgun (WB7 pg173): 1000ft underwater vs 2500ft (40%)
Kittani War Crab's Forward Rail Guns (WB7 pg182): 2000ft underwater vs 4000ft on land (50%)
TXP Quad Rifle (WB7 pg198): 1400ft underwater vs 6000ft (23%)
X-6000 (WB7 pg200): 1200ft underwater vs 4000ft surface (30%)
TXS-800 (WB7 pg202) : 1200ft underwater vs 4000ft surface (30%)
TSX-600 (WB7 pg201/203): 1200ft underwater vs 4000ft surface (30%)
Sea SAMAS PA's #2 Rail/Ion Gun (SB4 pg50-1): 2000ft underwater vs 3000ft on land (66%)

6x examples have their range reduced by more than 50%, 1x example reduced by 50%, 1x example that is reduced by less than 50%.