It coming up soon in our campaign, and I am interested in seeing a few ideas about them, best backed up by sources and comparisons between existing ordnance systems in the game. Let some good thoughts, ideas and resources gather in this topic for them.

The ability for a few Y-wings to cripple a star destroyer basically at will can be a game breaker if allowed to freely

Sure, we're dealing with retroactive continuity, but given the bombs' effect in Rogue One, I'd probably give them a high rarity and make them restricted, because their effectiveness at Scarif (where they still saw limited use...just the one Star Destroyer) begs the question of why they weren't used at Endor.

Either that, or the disabling of the ISD would be (in game terms) one or more triumphs narrated as one of the bombs just happening to impact a system that started a cascade failure of the ship's systems, and is not indicative of the normal scale of their effects.

ETA: Thinking about it, I prefer the latter. Because if that is indicative of their normal effects, why not use them on the shield gate?

The endor question can be answered easily, a squadron of B-Wings will not only cripple but downright destroy a star destroyer in a single volley with proton torpedos. We did not see much B-Wing action in movie, but the B-Wings were supposed to really wrecked havoc among the imperial fleet, IIRC a single squad of them at endor took out a dozen ISDs in that battle. That is backed up by the game rules as well: Proton torpedos are indeed that devastating against capital ships, based on how easy it is to crit with them, combined with the very high base damage and breach to pierce extreme high armor values of imperial star destroyers.

For the shield gate: The shield gate is just an installation to open a hole in the planetary shield, it is not the source of the shield, so ionising the whole thing seems not like something which should interrupt the shield.

In regards to the Star Destroyer, while we see the Y-wings take a pass and disable it, we don't know it's exact in-game mechanics condition when the ion torpedo attack was executed. Likewise which mechanics were even being applied.

1) If the star destroyer had taken several Strain inducing hits already, be it from ship ion cannons or crits, and rolled threats regularly (easy if it was trying to directly engage the fighters instead of merely trying to defend itself with the barrage option) then the players could correctly assume the star destroyer was ripe for disabling. In which case the ion torpedoes need not be any more powerful than regular ones. The Star Destroyer was just already low on system strain and the y-wing strike put it over the edge.

2) Was the space battle even an actual direct player action battle? If we assume the Rogue One crew was the players then the space battle was a Mass Combat driven narrative action, not an actual fight with players rolling actual to-hits and so on. It just explained what was going on up there while the players fought the real fight down below. In this interpretation, the ion torpedoes didn't even have stats, the players just rolled a successful mass combat check with the right results to say the SD is disabled, and the narrative method was the Y-wings.

3 hours ago, korjik said:

The ability for a few Y-wings to cripple a star destroyer basically at will can be a game breaker if allowed to freely

They were a bad idea story wise. Why didn't the rebellion buy/steal an F ton of those? Why didn't they shoot them at the stupid gate station instead? Why would they be in a panic about engaging the empire if their strike fighters can disable cap ships and fight their way through 10 fold opposing fighters?

I liked the scene, but in game mechanics I quickly filed Ion Torpedoes in the Midichlorian file.....

21 minutes ago, 2P51 said:

They were a bad idea story wise. Why didn't the rebellion buy/steal an F ton of those? Why didn't they shoot them at the stupid gate station instead? Why would they be in a panic about engaging the empire if their strike fighters can disable cap ships and fight their way through 10 fold opposing fighters?

I liked the scene, but in game mechanics I quickly filed Ion Torpedoes in the Midichlorian file.....

The attack on the Rebel base happened not long after Scarrif. All of their ion torpedoes were used in the battle of Scarrif. Ta-da! that part is solved. As far as Endor, no clue. Maybe they weren't able to take any ion weaponry when they left Hoth.

The Y-Wing torpedo run is probably my favorite scene from Rogue One:

After gleefully playing the scene over and over studying the scene, some points to mention:

1) The shield generator tower was destroyed in a previous engagement. In an RPG game, I'd rule that the shields must be brought down before before the torpedoes can have their devastating effect.

2) The Star Destroyer was hit with over twenty torpedoes before the ship was properly disabled. In an RPG game, I'd probably let players take out specific subsystems of a ship with Ion torpedoes, but to disable the ship proper, it would need lots of successful attacks in order to work.

3) If not for Raddus' quick thinking to hit a Star Destroyer with another Star Destroyer (Imperial Fleet captain was an idiot for keeping his ships so close together and killing their maneuvering room), I'm sure the imperial damage control teams would be getting their ship back online. In an RPG game, I'd have the Star Destroyer crew immediately taking damage control actions to bleed off the system strain incurred by the Ion damage. We all know that Star Destroyers and Mon Calamari Cruisers mount a regular armament of Ion cannons, so I'd say that being disabled by Ion strikes is a regular enough occurrence to warrant crews already knowing what to do.

48 minutes ago, SEApocalypse said:

For the shield gate: The shield gate is just an installation to open a hole in the planetary shield, it is not the source of the shield, so ionising the whole thing seems not like something which should interrupt the shield.

And yet the ISD being plowed into the gate took out the shield, enabling the transmission of the plans (and the Death Star's strike on the Scarif base).

39 minutes ago, Ghostofman said:

In regards to the Star Destroyer, while we see the Y-wings take a pass and disable it, we don't know it's exact in-game mechanics condition when the ion torpedo attack was executed. Likewise which mechanics were even being applied.

1) If the star destroyer had taken several Strain inducing hits already, be it from ship ion cannons or crits, and rolled threats regularly (easy if it was trying to directly engage the fighters instead of merely trying to defend itself with the barrage option) then the players could correctly assume the star destroyer was ripe for disabling. In which case the ion torpedoes need not be any more powerful than regular ones. The Star Destroyer was just already low on system strain and the y-wing strike put it over the edge.

2) Was the space battle even an actual direct player action battle? If we assume the Rogue One crew was the players then the space battle was a Mass Combat driven narrative action, not an actual fight with players rolling actual to-hits and so on. It just explained what was going on up there while the players fought the real fight down below. In this interpretation, the ion torpedoes didn't even have stats, the players just rolled a successful mass combat check with the right results to say the SD is disabled, and the narrative method was the Y-wings.

Regarding 2), I'm looking at the original question from the perspective of players seeking to recreate the results seen on screen.

The Rogue One group may have been that campaign's PCs, but the proton bombs are now gear that players in another campaign can get their hands on and expect the results seen on screen.

In which case my option 1) backed by Snicket's observations seem to be your answer.

Take an existing torpedo, add the Ion quality, increase the crit requirement and decrease the damage a bit to be consistent with other ion weapons, and that's that.

The star destroyer in Rogue One had already been taking system strain for several turns, and probably earned some of its own through threat. So by the time the Y-wings hit it it's already ripe for disabling.

2 hours ago, GroggyGolem said:

The attack on the Rebel base happened not long after Scarrif. All of their ion torpedoes were used in the battle of Scarrif. Ta-da! that part is solved. As far as Endor, no clue. Maybe they weren't able to take any ion weaponry when they left Hoth.

That's a pretty thin plot hole plug, and of course it doesn't explain why the Empire doesn't have a S ton of them. They work great, a half dozen fighters disabling a cap ship. It's a bad story element.

Well, half a dozen fighters disabling a large ship was real life that the movies were inspired by, so I don't see a problem with it. I'm sure it happens all of the time, but we just don't see it on the screen. Trying to mimic the snippets of action we see on the screen perfectly with the game rules and not assuming that there is a lot more going on that we don't see leads down the wrong path for this game IMO.

2 hours ago, 2P51 said:

That's a pretty thin plot hole plug, and of course it doesn't explain why the Empire doesn't have a S ton of them. They work great, a half dozen fighters disabling a cap ship. It's a bad story element.

If you use proton torpedo instead, you need 6 advantages per shot for two critical hits per shot and a guaranteed double critical hit, 6 TIE or Alliance Aces should actually be able to do just that. So why bother with Ion torps when proton torps give you kills not just a temporary disabled ship?

Though I was searching more in lines of if those ion torps should have similar breach values or smaller ones than their proton torp brethren, instead we get a pretty fundamental discussion about plot holes in a series which has 1g gravity on a small asteroid ;-)

4 hours ago, Nytwyng said:

Regarding 2), I'm looking at the original question from the perspective of players seeking to recreate the results seen on screen.

The Rogue One group may have been that campaign's PCs, but the proton bombs are now gear that players in another campaign can get their hands on and expect the results seen on screen.

BTW, you misunderstood me there. I am not looking to recreate that scene, I actually did not even thought about rogue one when asking about them. ;-)
We just happen to get our hands on some ion torpedos and a imperial raider has captured some of our friends and blockages our escape. My angle is the x.wing games, be it miniture or space sim.

And my own idea would be to hand out something around the concussion missile stats with the ion quality and an increased crit rating. But that is more a feeling out of balance and out of how FFG wrote concussion mines and ion mines in No Disintegrations. But I am looking for other ideas how to handle them, because I might be overlooking something.

It is because Star Wars is not about thousands of soldiers doing their job, it is about a few heroes (or even just one) turning the tide of battles. If fighters/bombers were unable to hurt capital ships, why have them at battles at all? Why deploy fighter screens if the enemy fighters are useless? The whole concept of Star Wars space combat is obviously based on WWII naval warfare, especially in the Pacific Theatre, with planes becoming the biggest threat to surface vessels, even powerful battleships, and carrier warfare coming to the fore. It fits the "one pilot striking true" theme of the very first Star Wars movie.

The Empire was surprised at Scarif. It is supposed to be pretty much the first large-scale space battle fought by the Rebel Alliance (and they do get their asses handed to them in the end, to be fair). Surprise is a very big factor in warfare, and the rebels used it to their advantage, with the Empire not really knowing their capabilities and not expecting an attack at all. Afterwards, they got better at this whole fighting rebels in fleet actions thing.

Why did the rebels not use them at Endor? Their ships were fitted to attack the Death Star, not tangle with the Imperial Fleet. Why would they carry ion weaponry when attacking a battlestation of that size?

I mean, if you start to ask questions like that, you also need to ask why the TIE fighter complement of the Death Star is so small. Or why they build kilometre-long capital ships with bridges that have actual windows that one fighter can crash into. There are so many instances like that, because Star Wars film battles are obviously more geared towards cinematic effects than anything else.

I did concoct some ion missiles (personal scale, vehicle scale, and mini missile). They're pretty straightforward though, just using the base concussion missiles and raising and lowering a few numbers.

Hopefully with Fully Operational will provide some of this stuff.

it my game I recreated the Mag-pulse torpedoes. They bypass shields and disable a ships weapons temporarily. The ships can move, but has no "Teeth" which allows for a poorly armored ship or fighter impunity to attack it.

IMHO they are better than Ion Torpedoes for game balance wise then ion torpedoes since Ion cannons still have to deal with shields.

If the Star Destroyers deploy even 1% of their crew to performing damage control each turn, they can reduce System Strain so fast that Ion weapons are virtually useless.

I think those Y-wings disabling the ISD was just a couple of really lucky shots. The Y-wings probably had the intent to wreak havoc on the ISD's systems and focus its energies towards repair rather than offensive maneuvers, but I don't think they actually thought they were going to cripple the ISD entirely. Raddus sounds surprised when he says "that Star Destroyer's disabled," just before he orders the Hammerhead in.