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Hi all,

I was curious as to whether these would work underwater?

lasguns
For lasguns i'm leaning towards the fact that they would, since it's not a projectile of sorts, more of a short burst of energy. If they can the other problem i can see is if firing on full auto the water would get quite warm i imagine
Also firing into water, would there be diffraction?

Boltgun
I imagine this wouldn't be too much of an issue since they're self propelled, so they'd hit with less force from the water resistance but the explosive nature of them would still be sufficient enough to do almost the same amount of damage as if on dry land/space/anywhere not in liquid

Any references as to these ever occuring? Or any typical weapons(plasma, melta) being fired underwater?

Theres no water in the 40k universe you silly billy it got replaced by a grimmer darker alternative.

ChronoCupcake wrote:Theres no water in the 40k universe you silly billy it got replaced by a grimmer darker alternative.

My bad, let me rephrase that: say if a marine(or void suit guardsmen) dove into a pool of blood to fight demons would their guns still work?

ChronoCupcake wrote:Theres no water in the 40k universe you silly billy it got replaced by a grimmer darker alternative.

Like Red Bull *shudders* truely mankind is doomed.

Underwater, the lasgun might fire but the diffraction of the water would, most likely, seriously limit the range of the laser-bolt or its stopping power. It would also probably create a lot of steam-bubbles around the weapon's muzzle, potentially spoiling aim and reducing the effectiveness of scopes or targeters.

Bolt guns would almost certainly fire underwater, at most suffering a decrease in their effective range, due to water resistance on the shell.

i don't think the lasgun would fire, and if it did it would have massively shortened ranges, a few feet at most, as the energy loss from touching the water, causing evaporation, would be massive. boltgun would work almost perfectly though, unless water could get inside each casing or the interiors.

The boltgun absolutely fires underwater. I've read that somewhere, although I admit I am unable at present to find the original source. A lasgun I can't see being able to fire underwater. In point of fact, I think it would probably work out really poorly for the poor sap who tried.

I see, so the general consensus is the las would evaporate the water around the firer, leaving the firer pretty badly burnt.

How would melta or plasma go?
Melta may result in the same effect as las, just at a higher degree ie. a stream of evaporated water

Plasma i'm curious about, as it's contained in a magnetic field of sorts(correct me if i'm wrong) would that keep the water off it until it impacts with something?

Also if a bolt shell was fired at water would the impact with the water be sufficient enough to make the shell explode? As bullets lose quite alot of their velocity when they hit the water

Didn't the Space Wolves fight an entire battle underwater against the Tau or something I will try to search for it tomorrow, but I'm tired now.

The lasgun would probably work in the water, but it'd still be rather painful from superheated water rushing up against them (water being more dense than air so more is heated up) and it'd waste more energy sooner than it would in air or in a vacuum.

Nicholas wrote:Didn't the Space Wolves fight an entire battle underwater against the Tau or something I will try to search for it tomorrow, but I'm tired now.

Yeah but there is little detail...

I think that melta and plasma weapons would be uncomfortable or injurious for the firer, although they would still work (perhaps at a diminished capacity). The lasgun I think would have a different problem, which is the nature of water to refract light. And since that is all the lasgun is firing, I think it would be disrupted by the water far more than other weaponry.

A laser is a beam of light, light travels slightly slower in water. the only problem is the color of the laser. From the games, it is shown as red, which is the first color to disappear deep underwater. If they need range, a shorter wavelength would do the trick.

A plasmagun fires a (surprise!) a ball of plasma. I honestly don't know what would happen here, but the water may be advantageous when it comes to heat management. Thats all I can say on that.

The meltagun is very similar to a plasmagun, the main difference being the meltagun fires a column of plasma instead of a ball of it. It achieves this by agitating the air to a very high energy state, and it results in a column of plasma. Again, I don't know what would happen.

Shayden wrote:A laser is a beam of light, light travels slightly slower in water. the only problem is the color of the laser. From the games, it is shown as red, which is the first color to disappear deep underwater. If they need range, a shorter wavelength would do the trick.

A plasmagun fires a (surprise!) a ball of plasma. I honestly don't know what would happen here, but the water may be advantageous when it comes to heat management. Thats all I can say on that.

The meltagun is very similar to a plasmagun, the main difference being the meltagun fires a column of plasma instead of a ball of it. It achieves this by agitating the air to a very high energy state, and it results in a column of plasma. Again, I don't know what would happen.

Can the wave length of lasguns be changed? I know certain pattern lasguns have alternate settings, so would the high setting shorten the wavelengths?

My thoughts about plasma are that the water would cool the gun alot better so it wouldn't overheat as often and that the plasma is contained within the magnetic field until it's disrupted, but does it give off it's heat while its in the magnetic field? Thus still having the same heat problems as the lasgun.

Melta doesn't have a magnetic field but like you said reacts with the air, in this case it would be the water that becomes aggitated, i'm thinking that it's effects would be enhanced as water is denser than air, as was mentioned, so it would be a hotter beam, range would be the same and i think it would yield the same heat problems as plas and las. Firing it into the water would be fine IMO though

Thoughts?

in several gaunts ghosts novels the imperial las round is blue whilst the heretic las round is red, so maybe underwater is the best place to boil the heretic as you have far superior range

Gaunt's Ghosts also describes lasguns as firing slower than light projectiles (which are affected by things like wind speed, and require the shooter to take things like bullet drop into account... ) and occasionally being fitted with silencers, which actually work for them...

Plasma and Melta guns would cause a huge problem if fired underwater. Both would superheat and flash-boil vast amounts of water, dissipating the heat/plasma energy and, most likely, causing a massive overpressure wave.

Now, considering that force is transmitted very effectively through water (hence depth charges are hugely damaging to submarines) then the pressure wave resulting from an atomic thermal weapon or plasma gun would, at best, knock any unaugmented human unconscious, if not cause internal damage. On top of this you have the likelyhood of causing severe burn or scalding damage from the mass of superheated water/steam.

Even if an Astartes was to fire the weapon, they'd lose all visibility and the enormous amount of noise, thermal energy and kinetic disruption would leave them blind and confused for a short, but significant, time.

Not a good idea, kids. Remember: No Meltas or Plasma Guns in the Pool.

I wonder what power weapons are like underwater?
Boltguns would lose most of their speed in the water, would they not?

Divine Comedy wrote:I wonder what power weapons are like underwater?
Boltguns would lose most of their speed in the water, would they not?

For the boltgun: Water is more dense than air, therefore more friction => slower bolt.

Since lasguns are effectively beams of light, the refraction would make any aiming pretty much useless.
Boltguns would fire, but much slower. I recall there was fluff somewhere about an underwater battle between SMs and some others, I think Tau.
Plasma and melta would lose most of their power.

For the boltgun, water inside the barrel would cause overpressurization problems when you fire the gun (there is still a conventional powder charge that accelerates the bolt out of the gun, before the bolt's own rocket ignites). Try firing an assault rifle underwater and see what happens.

(Pro Tip: It doesn't end well!)

Your barrel could very well crack, to say nothing of what happens when water gets inside your breech when your frist shell is ejected... Best case scenario is your gun stops working after one shot. Worst case scenario is you drown and/or bleed out after your gun explodes in your face.

For a gun to fire underwater, it must be specialy modified and sealed. There is an underwater-capable AK-series gun floating around IRL, but I don't know of any others.

Plasma... plasma.... hmmm... that's a tough one. The magnettic bottle the plasma is encased in drops when it meets obstruction (a tank, a guy, a guy in power armor, etc)... while air doesn't obstruct the shell (not dense enough) water very well might. I can't say for certain (since there is NOT an underwater-capable plasma gun IRL... or any plasma gun for that matter) what would happen, but I would think it likely the plasma shell would just detonate as soon as it leaves the barrel.

Wear your safety goggles, kids!

As for melta, I can't think of why that would be a good idea either. According to the older, more detailed fluff on the weapons, the melta gun is a microwave gun. It "agitates the targets molecules" and "superheats the target's moisture" till it explodes. It's like murdering your enemy with a microwave oven. Remember the scene in Gremlins?

So if it causes moisture to superheat and explode... umm... pulling the trigger underWATER might be the last bad idea you ever have.

Lasguns I'm not sure about. If they fire a packet or bolt of laser at a target, then it's possible the water might disrupt it immediately. Then again, it might still function as advertised, though at a much reduced range. If they fire a solid beam of laser, then it would definately function. The water heating up would only be a problem after prolonged firing, or shooting a few times and then trying to move through the area you just fired into.

Autoguns would die the same death as the bolter.

Flamers would not function at all. The Promethium would not ignite in the water, and also, it would not leave the fuel tank if the water pressure was greater than the pressure inside the tank.

Shuriken and Splinter weapons might function (they don't use propellant as far as I know) but they would have a reduced range and accuracy.

Ork Shootas would... umm... you know what? It's best not to get into a debate about the functional properties of Ork weapons.

So, in the grimdark 41st millenium remake of Thunderball, everybody is still using spearguns.

Sir Pseudonymous wrote:Gaunt's Ghosts also describes lasguns as firing slower than light projectiles (which are affected by things like wind speed, and require the shooter to take things like bullet drop into account... ) and occasionally being fitted with silencers, which actually work for them...

It says absolutely NOTHING about "being fitted with silencers". The longlases were fitted with flash suppressors, which were mentioned as being part of the reinforced barrel anyways. The only time silencers have been used is on solid ammunition weapons. Most notably, "Guns of Tanith" had them for the Infiltration Team.

There is also no evidence given about lasbolts being affected by things like wind speed, and the shooter having to take things like bullet drop into account.

That was Larkin lecturing a figment of his imagination, when asked about what he was doing while setting up for a shot. Larkin was noted as having operated solid slug weapons regularly during his stint as a Gamekeeper and whilst hunting Larisel, and just because he continues doing things a certain way(such as finding the point where his aim is naturally going to settle) does not necessarily mean that all of it applies, or that he's doing all of it.

Divine Comedy wrote:I wonder what power weapons are like underwater?
Boltguns would lose most of their speed in the water, would they not?

I imagine they would still function, since it's not electricity, it's a power field, the water around the blade would dissolve though. Which may cause a problem :question
I'm interested to know how a shock staff would(or wouldn't) work though, whether it is actually electricity, which would obviously be a massive problem

squidhills wrote:For the boltgun, water inside the barrel would cause overpressurization problems when you fire the gun (there is still a conventional powder charge that accelerates the bolt out of the gun, before the bolt's own rocket ignites). Try firing an assault rifle underwater and see what happens.

(Pro Tip: It doesn't end well!)

Your barrel could very well crack, to say nothing of what happens when water gets inside your breech when your frist shell is ejected... Best case scenario is your gun stops working after one shot. Worst case scenario is you drown and/or bleed out after your gun explodes in your face.

For a gun to fire underwater, it must be specialy modified and sealed. There is an underwater-capable AK-series gun floating around IRL, but I don't know of any others.

Plasma... plasma.... hmmm... that's a tough one. The magnettic bottle the plasma is encased in drops when it meets obstruction (a tank, a guy, a guy in power armor, etc)... while air doesn't obstruct the shell (not dense enough) water very well might. I can't say for certain (since there is NOT an underwater-capable plasma gun IRL... or any plasma gun for that matter) what would happen, but I would think it likely the plasma shell would just detonate as soon as it leaves the barrel.

Wear your safety goggles, kids!

As for melta, I can't think of why that would be a good idea either. According to the older, more detailed fluff on the weapons, the melta gun is a microwave gun. It "agitates the targets molecules" and "superheats the target's moisture" till it explodes. It's like murdering your enemy with a microwave oven. Remember the scene in Gremlins?

So if it causes moisture to superheat and explode... umm... pulling the trigger underWATER might be the last bad idea you ever have.

Lasguns I'm not sure about. If they fire a packet or bolt of laser at a target, then it's possible the water might disrupt it immediately. Then again, it might still function as advertised, though at a much reduced range. If they fire a solid beam of laser, then it would definately function. The water heating up would only be a problem after prolonged firing, or shooting a few times and then trying to move through the area you just fired into.

Autoguns would die the same death as the bolter.

Flamers would not function at all. The Promethium would not ignite in the water, and also, it would not leave the fuel tank if the water pressure was greater than the pressure inside the tank.

Shuriken and Splinter weapons might function (they don't use propellant as far as I know) but they would have a reduced range and accuracy.

Ork Shootas would... umm... you know what? It's best not to get into a debate about the functional properties of Ork weapons.

So, in the grimdark 41st millenium remake of Thunderball, everybody is still using spearguns.

Ah so lasguns should be ok on high power settings, as long as you don't swim in the direction of the bullet This helps alot, thanks
As for plasma weapons i have no idea what it takes to set off the energy field, whether it needs to be a solid object, since i imagine they where designed for use on different worlds where gravity would affect the pressure on the magnetic field, i think they just might work

motorhead1945 wrote:

Divine Comedy wrote:I wonder what power weapons are like underwater?
Boltguns would lose most of their speed in the water, would they not?

Power weapons are not simply weapons which are sheathed in electricity.

The Promethium would not ignite in the water

Promethium doesn't necessarily take oxygen to ignite, as it works in a vacuum. The water may still put it out though.

A laser beam is a form of highly focused light so, therefore, the lasbolt would refract and fly off at an angle.

A Bolter shell would just slow down. Its called water resistance for a reason.

Melissia wrote:

The Promethium would not ignite in the water

Promethium doesn't necessarily take oxygen to ignite, as it works in a vacuum. The water may still put it out though.

Surely not? I mean, if it works in a vacuum, what would water offer that would cause it not to? Lack of oxygen clearly isn't an issue, otherwise it wouldn't ignite in a vacuum. Would the pressure make a difference?

A melta underwater would be a phenominally bad idea.
You'd end up like a flash-boiled lobster.

Plasma bolts are still hot even when they haven't impacted, so boiling water is probable, and energy loss is almost definitely a factor. Reduced range and power, and some user-related burns would probably be the result.

Firing a melta INTO water could be interesting, you'd get a gout of superheated steam which might be useful: "Aah! my eyes!"

An unmodified bolter round would probably work horribly under water. Would the rocket motor even be able to ignite properly? Would the mass of the water be enough to set off the explosive? What you would want is a modified round that incorporates tech that would allow it to supercavitate, and you'd also want to modify the explosive to be impact, or delay on impact, rather than mass reactive.

Firing a plasma or melta weapon underwater would just be suicide.

Unmodified bolters wouldn't work underwater because the water could stop the bolts fuel igniting. The resistance of the water is going to slow down the bolt (much more than a standard bullet) and the extra force required to move it will burn fuel at a much faster rate. Given the amount of different bolter modifications there are I imagine there is one that works underwater.

Melta and Plasma weapons would lose all their heat to the surrounding water and probably cook the user.

Lasguns may work at very short range. The light would be absorbed much faster. All normal light is absorbed after about 30/40 metres so they would be almost useless.

Flamers could work. It depends on how hot the fuel burns and whether it has its own source of oxygen (which it appears to). We already have fules that can burn underwater so I don't see that as a problem. The main issue I can see is that to be a useful weapon you need a large flame. This would heat up the water around you, boiling you. You would also need to find a way to control the flames. As strong current is going to push the burning fuel back towards who every is using it.

Autoguns could work underwater but we don't know. It depends on the build of the weapon.

The IoM alomst certainly do have weapons that work underwater but they are probably modified version of the current weapons.

MikZor wrote:

Shayden wrote:A laser is a beam of light, light travels slightly slower in water. the only problem is the color of the laser. From the games, it is shown as red, which is the first color to disappear deep underwater. If they need range, a shorter wavelength would do the trick.

A plasmagun fires a (surprise!) a ball of plasma. I honestly don't know what would happen here, but the water may be advantageous when it comes to heat management. Thats all I can say on that.

The meltagun is very similar to a plasmagun, the main difference being the meltagun fires a column of plasma instead of a ball of it. It achieves this by agitating the air to a very high energy state, and it results in a column of plasma. Again, I don't know what would happen.

Can the wave length of lasguns be changed? I know certain pattern lasguns have alternate settings, so would the high setting shorten the wavelengths?

My thoughts about plasma are that the water would cool the gun alot better so it wouldn't overheat as often and that the plasma is contained within the magnetic field until it's disrupted, but does it give off it's heat while its in the magnetic field? Thus still having the same heat problems as the lasgun.

Melta doesn't have a magnetic field but like you said reacts with the air, in this case it would be the water that becomes aggitated, i'm thinking that it's effects would be enhanced as water is denser than air, as was mentioned, so it would be a hotter beam, range would be the same and i think it would yield the same heat problems as plas and las. Firing it into the water would be fine IMO though

Thoughts?

I'm sure the cogboys can work their magic on the lasers. Wavelength changes shouldn't affect the intensity AFAIK. Again, as for the plasma and melta weapons, I don't know what would happen.