I'm outfitting a Dominator-class Cruiser and I'm curious as to how useful certain Components will be for an assault ship. While the Invasion Bridge, BG-15 Assault Scanners, Barracks, and Drop Pod Launch Bays are all obvious in how useful they will be, there are a few others that leave me wondering.

Nova Cannon: The ship comes with this, so it's going to be there. It seems like it will be great for punching holes in orbital defenses (and possibly minefields) from a standoff distance. However, I am wondering if this is also useful for direct bombardment of ground targets. I have never heard of weapons other than Macrobatteries and Lances used for orbital bombardment, so is it even possible to bombard with a Nova Cannon?

Disruption Macrocannon Broadsides: Is there some reason that these could not be used to bombard? I like the idea of knocking power out over a large swath of ground - hitting hive cities, ground-based defense weapons, etc. so that they can be captured relatively intact by the troops the ship is dropping.

Torpedoes: This ship will not be mounting Torpedoes, but otherwise this is the same question as with the Nova Cannon - can Torpedoes be used to bombard ground targets?

I'm pretty sure that whatever you fire that Nova Cannon at will disintegrate. I refer to http://forums.tauonline.org/40k-universe/49706-nova-cannon-firepower-calculation.html ] for calculation on this kind of thing. It is really stupidly powerful. I recommend reading the thread to see for yourself, but they really are immensely powerful.

A macrocannon should be able to bombard pretty much everything, so I don't see this as a problem. Possibly the payload goes off upon atmospheric entry, but it'll still spread nastiness upon the area, considering the size. I refer to this:

Aight, it was a bit hard to read, but right-click and show the whole image for a better idea of it all.

So yes, bombarment should not be an issue.

I wasn't sure if the shell of the Nova Cannon - which in RT we all know is an explosive charge (with an explosive radius of 10,000 km in space!) and not a high-density penetrator - would be able to survive atmospheric interface. I read the link you sent, and the calculations are absurd. They try to strictly apply physics at some points and totally ignore them at others. Far better I think to use the same level of "fuzzy physics" on both sides.

So, if a Nova Cannon was used in atmosphere, what would be a reasonable area for the explosion to cover?

As for the disruption macrocannons, they don't fire solid shells but instead charged packets of energy. Again I'm wondering if these will survive atmospheric interface well enough to be used to bombard ground targets. I don't really see why not, but I've never heard of such weapons used for these purposes in WH40K before.

Generally I do not allow torpedoes and nova cannons for planetary bombardment, unless they have a special delivery system that gets them through the atmosphere. Novacannons however would likely, in my opinion still damage ground targets if it detonated on the atmosphere. In general though, I wouldnt do it If I wanted to conquor something, as you wouldnt have much left to conquer. As for disruption cannons I would rule one of two ways. 1- the discharge is disipated in the atmosphere. Or 2- each point of strength that hits, disables one electronic system. Weather that be a cities power grid, a towers emergency generator or a single vehicle all depends on what you hit. I would not have it whiping out entire armored battalions though.

Personally if I was going to build for planetary assault, I would go for bombard cannons over a nova cannon. I like the idea of a secutor monitor light crusier with two bombard cannons and two escort landing bays, drop pods, barracks, teleportarium, invasion bridge, assault scanners and munititorium. Get some good turbo weapon upgrades on the bombardment cannons and try to find a castellan shield array and your good to go.

Cryhavok said:

Considering that a macrocannon shell can take out way more than a single vehicle - covering a vast area in ruin, I'd think that a barrage of disruption cannons could leave behind a battlefield where nothing electronic was left operating much like a sci-fi version of directed EMPs. The power could be restored after some time (likely requiring at least 30 minutes of work if the starship combat rules have anything to say about it), but the defenders might not get that long to spend tinkering with the gear if the drop pods are coming down on them! Captured gear can be better than destroyed gear!

And, as for the ship type, it's going to be a Dominator. It's not ideal, but it's what's there, so the Nova Cannon and Armoured Prow are set in stone for this one and it's going to have macrocannon broadsides but I'm considering Disruption Macrocannons over Grav-Culverins for this purpose.

Cryhavok said:

Makes some sense, but I'm not sure how to work out what gets directly hit by orbital bombardment. I always took it to be more of an area saturation thing than pin-pointing targets. Lances can pin-point target, but not against things smaller than titans/superheavy tanks.

Page 135 of battlefleet kronus has the rules for aiming your bombardment. As a macrocannon barrage fires multiple shots, I would center the first one at the middle of the effect, and use scatter rule for the others, using hunderd meter units for how far each blast scatters within the ten kilometer radius

Mostly though, what gets directly hit is gms call on how they want to handle it. You could just as well hit things directly at the need of the story.

Cryhavok said:

The rule you are quoting is for a single "battery" attack not a single weapon. That being said I would rule that within the affected area all power grids and electrical based systems would be effectively knocked out unless it was specifically shielded (Like most military kit is!). Individuals within the affected area would be as if attacked by a Haywire grenade. The reason for this is exactly as the OP intended: Large scale power systems would be more seriously affected than individuals. Of course one must remember that Major cities usually have Void shields that can shrug off a cruiser's bombardment. Additionally, They can usually shoot back with a powerful array of ground based Lance batteries, Torpedoes and other nastiness!

Radwraith said:

I very much doubt that a Leman Russ would count as shielded against such surges if a Lunar-class Cruiser is not. I don't see much evidence that any Imperial tech has such specific protections.

When firing a Nova Cannon at a target on a planetary surface, how would a "shot goes long" result work? Would the shell be destroyed by impact with the planet before it could detonate?

About disruption weapons: so you would have them shoot at a one kilometer long ship and only take out a small number of systems, but when shot at a planet whipe out every electrical system within ten kilometers? How does that work?

Cryhavok said:

Not every system, but they would still do damage like macrobattery bombardment, but only to armour/mechanised infantry/power armoured infantry/aircraft units and fixed defenses in the 10 km square. The damage done would be temporary, as the systems could later be restored. If the unit that's been disrupted is 'destroyed' then it's possible that their assets could be captured relatively intact and repurposed by whoever claims the battlefield.

I would also say that it's likely that any starship has FAR more shielding from such disruptions than any land-based mobile unit (although fortresses and other fixed defenses are much more likely to be protected like very large starships).

Ah okay, that makes sense.

The other potential problem I can see with using Disruption Cannon for orbital bombardment is you're going to leave a really cruddy ground-to-orbit vox reception, so spotting for correction of shots is going to be problematic, but if you're using it as a technic area-denial weapon then odds are you're not necessarily too bothered about using ground-based forward observers (well, you might be if follow-up shots are from other weapons systems).
Also, it'd only be a problem for vox links if you're shooting through an atmosphere, so airless worlds and/or psychic communication would not be bothered by a sudden large ionized mass of air above them.

And while the RAW* say you can't bombard with torpedoes (as yet, anyway), in fluff, and Battlefleet Gothic, you can. Hell, that's one reason you use ground observers, to guide in projectiles capable of course correction and terminal guidance (and anti-starship torpedoes make some of the best bunker-busters out there).

*I could be wrong, I don't have my copy of BfK for reference just now; it might just ban virus warheads on orbital bombardment torps. I believe the rationale was explicitly to prevent players from getting their hands on exterminatus grade weaponry.

In DW RoB They talk about torpedoes being used in orbital bombardment as a support option. I would think that a Nova cannon fired at a planet's surface would be an almost Exterminatus grade weapon for any # of reasons!

@ Cry havoc: The reason I wrote that was that your post gave me the impression (Perhaps wrongly) that you were referring to one gun within a given weapon mount. Whereas the damage referred to in BfK is from a gun mount conducting bombardment for 1 groundwar turn (Which would be 3 hrs or 6 "shots" from any given macrobattery mount.). I meant no offence. Just trying to clarify!

The Storm Drop pod launcher is not as obvious as one might think. Unless your ship is carrying Space marines or Battle sisters it's of limited use to you.

Radwraith said:

Is there a reason that standard armsmen can't use drop pods for deployment? The idea of the ship is to quickly disable target ships and allow for boarding. The secondary use is to do the same to installations, and for this the drop pods seemed like a good way to rapidly deploy the troops.

Alasseo said:

I'm not sure that the energy packets fired by the Disruption Cannon are going to discharge from atmospheric contact - they seem to 'pop' when they strike a target. Regardless, they won't hit anything outside of their 10km square, and if our observer was there, it wouldn't matter what weapon you're using. At least this way only his electronics go down (so directing fire by astropath would be a way around this).

For my players, I make them get special torpedos for orbital bombardment, that are capable of atmospheric entry. None have tried to get them yet, so none have done bombardments with torpedos.

HappyDaze said:

Uh, broken legs?

Gavinfoxx said:

There's no reason for that. The pods obviously are designed to allow for rapid safe deceleration. There is nothing in the descriptions of the pods that states they can only be used by specific troop types.

HappyDaze said:

http://warhammer40k.wikia.com/wiki/Drop_Pod

Apart from the fact that i have never come across any hint of non-astartes drop pods. Even the Eversor temple drop pods can be assumed to be considerably different from an astartes one (smaller and stealthier with a lot less speed behind them - 12,000 KPH will squish a standard human on impact and even the enchanced Eversor would get massively injured in an astartes drop pod).

Personally i dislike that drop pods were ever included as a ship option in Rogue Trader without specifying what can use them. Combat servitors and Astartes, plus some higher end humans like tech-enchanced techpriests, inquisitors and officio assasins are about all i can imagine using them.

Imperial guard make use of grav chute drops and valkyries for deep striking, otherwise they just land in bulk troop and armour carriers and then mobilize en masse from their LZ.

Considering that Strom trooper regiments were a ship upgrade option in the same book as Drop Pod Bays i'd lean towards saying it is only they that can use them.

12,000 kph to stop is about 10g (+ local gravity) for about 30 seconds.

Real world pilots can withstand 9g axial with spine with a pressure suit. 16g is bearable if you a lying flat on your back (for young very fit men…)

Storm drop pods use caccoons to protect non-Astartes. I imagine Grav tech or simple liquid immersion could make 30g bearable, making the landing burn only 10 seconds..