I’ve been thinking about jump travel in Mothership. Here’s a quick summary, as described in the core rulebooks:

• Jump points are rated from Jump-1 to Jump-9.
• Utilizing a jump point requires a jump drive of equal to higher rating.
• For the crew of the ship, the jump always takes 2d10 days.
• Jumps usually seem to take the same amount of time for the rest of the universe, but each jump carries the risk of an unusual time dilation: Ships might disappear for months or even years instead of days.
• The longer/higher rated the jump, the more dangerous and severe the time dilation appears to be. It’s possible that some of the Jump-9 deep space exploration vehicles that have gone missing will reappear a thousand years in the future.

The rulebooks, however, leave these time dilation effects up to the GM’s discretion. I thought it might be useful to instead resolve the mechanically.

TIME DILATION

When a ship performs a jump, roll 1d10 per Jump rating (e.g., if a ship is making a Jump-3, roll 3d10).

For each 1 rolled on a d10, the actual trip duration increases by one step:

• days
• weeks
• months
• years
• decades
• centuries

If you’re making a standard Jump-1, you have a minimal risk of the trip taking 2d10 weeks instead of 2d10 days. If you attempt a Jump-3, on the other hand, there is a 1-in-1000 risk that you’ll roll three 1’s and return 2d10 years later.

Note: This does not change the subjective time experienced by the ship. For the crew, a jump trip seems to take 2d10 days, regardless of how much time passes in the wider universe.

Other Chaotic Effects: At the GM’s discretion, each 1 rolled on the time dilation check instead triggers a different chaotic effect. Examples might include:

• a crew member is replaced by a completely different person
• time dilation is inverted (the trip takes minutes or seconds instead of days) or reversed (they arrive before they left)
• subjective time experienced by the crew is dilated instead
• strange hallucinations or manifestations
• crew is unexpected awoken from cryosleep during the voyage
• the ship arrives in the wrong place

ASTRONAVIGATION

Calculating a jump requires an Intellect (Hyperspace) check. This check is made with [+} if the astronavigator remains awake during the jump, monitoring the astronavigation computers.

Success: You made it!

Critical Success: Roll one fewer d10 when making the time dilation check for the jump. For a Jump-1 trade route, roll 2d10 and only have the ship experience time dilation if both dice roll a 1.

Failure: Something goes wrong! The GM chooses one:

• Double the number of dice rolled for the time dilation check.
• The ship arrives in the wrong place. (1 in 10 chance you arrive back where you started after 4d10 days, having traversed a Calabi-Ricci spacetime loop.)
• The ship is damaged by jump turbulence, roll a Repair (SBT, p. 39).

Critical Failure: You could have killed us all! All three consequences of Failure happen simultaneously.

TRADE ROUTES

According to the Shipbreaker’s Toolkit, “regular Jump-1 trade routes seem to wear down the chaotic effects” of jump travel. Navigational calculations become more precise with each additional jump that’s recorded along a route, and ships traveling through the jump point can effectively wear a “groove” into spacetime.

At the GM’s discretion, ships jumping along a route which has been “worn” by regular travel reduce the number of d10s rolled for the time dilation check by one. For a Jump-1 trade route, roll 2d10 and only have the ship experience time dilation if both dice roll a 1.

UNCHARTED JUMPS

Most interstellar travel happens along charted jump routes: Jump points that have well-plotted navigational solutions (even if they shift slightly due to stellar drift) and are known to be stable.

These are not the only jump points in space, however. Once you’re away from planets, asteroids, and stations, it turns out there are many unstable points in the fabric of space which are constantly being created, destroyed, and shifting according to complex spacetime geometries.

The GM determines the base Jump rating of the uncharted route. (This can usually default to the total value of all Jump-ratings along the known path from the current system to the destination system. For example, if you could normally get to the other system through a known Jump-1 route, the base Jump rating for an uncharted route would also be Jump-1. If you would normally need to make a Jump-1 followed by a Jump-3, then the base Jump rating for the route would be Jump-4.)

Plotting the uncharted jump requires an Intellect (Hyperspace) check. This includes identifying the location of the jump point you need to use, which you will then need to travel to (as shown on the table below). If you’re in the Inner System or in orbit around a planet, increase the time required by one step. (Weeks become months.)

Success: Add 1d2 to the base Jump rating. This is the Jump rating of the uncharted route, which is then resolved normally.

Critical Success: -1 to the base Jump rating (minimum 1). In addition, roll 1d10. On a roll of 1, the jump path you’ve discovered is a new stable route. (Depending on the value of the route, selling the location of this new jump point might be worth thousands or millions of credits.)

Failure: Add 1d5 to the required jump rating. If you roll 5, roll again and add the result to the jump rating. If the result is 10 or higher, you have been unable to find any jump points leading to your desired destination.

Critical Failure: You thought you could get from here to there via a safe jump, but you were very wrong. Your Astronavigation check automatically fails. In addition, determine the jump rating as per a Failure, but you attempted the jump no matter what the result is. If the result was higher than the rating of your Jump drive, your ship suffers 1d2 MDMG and emerges from hyperspace in a completely random and unexpected location. (This is a good way to end up adrift in interstellar space.)

In Mothership, armor is rated in Armor Points (AP). Any damage you suffer is reduced by your current AP. However, if you suffer damage equal to or greater than the Armor’s AP, then the Armor is immediately destroyed.

I’ve been running Mothership for a while, though, and I’ve decided I don’t like this rule. The primary problem is that damage values in the system are high enough that armor is almost always immediately destroyed in the first hit. The intention is almost certainly to crank up the feeling of horror (not even your advanced battle dress can save you now!), but in practice it just feels cheap and kind of confusing. I’ve had multiple players new to the system who become completely baffled the first time they go into a fight, because it just feels as if something is wrong.

I’ve begun using the house rule below in my Mothership games, and we’ve had some pretty good success with it. It maintains the imagery of xenomorphs and nanoplagues slowly ripping their way through a PC’s armor, but it extends the experience over several rounds (which gives really great vibes at the table) without making armor feel pointless.

(And it works the other way, too, with PCs needing to apply significant force over time to cut their way through enemy AP!)

If you use these rules, let me know how it goes! I’m planning to continue tweaking these.

HOUSE RULE: ABLATIVE AP

If a character wearing armor takes damage equal to or greater than their AP value (including Cover), their armor becomes damaged and the AP of the armor is reduced by 1.

The armor is permanently destroyed if its AP is reduced to 0.

ANTI-ARMOR: An anti-armor weapon ignores AP. It automatically reduces AP by 1 on any hit and by an additional 1 point if it deals damage equal to or greater than the character’s AP value. On a critical hit, anti-armor weapons instantly destroy any armor, regardless of its AP value.

REPAIR: Damaged armor can be repaired with appropriate facilities for half the original cost of the armor.

Note: This rule does not apply to Cover. Cover is still immediately destroyed if an attack deals damage equal to or larger than the Cover’s AP rating.

In the Mothership RPG, when your ship takes megadamage it advances along track where each point of megadamage also inflicts an additional effect, as described in the Shipbreaker’s Toolkit, p. 35, and also on the ship manifest sheet:

00           All Systems Normal
01           Emergency Fuel Leak
02           Weapons Offline
03           Navigation Offline
04           Fire on Deck
05           Hull Beach
06           Life Support Systems Offline
07           Radiation Leak
08           Dead in the Water
09+         Abandon Ship!

Because you can suffer more than one point of megadamage per hit and you only apply the effect of the megadamage total you land on after, there is some variation within this system. But if you want to mix things up a bit more (so that, for example, you might suffer an emergency fuel leak after weapons go offline), you could deploy a basic megadamage pyramid:

You start on the top row and mark off boxes in a random order, once again only applying the last megadamage effect crossed off on each row.

Note: This pyramid is slightly less forgiving at the top end than the original rules, as it’s possible to hit Abandon Ship at 8 megadamage.

BRUTAL VARIANT: CAPRICIOUS FATE

Combat in the void is harsh and unforgiving, for this was a place that man was never meant to live or die.

In this brutal variant of the megadamage pyramid, each time a ship suffers megadamage roll the effect randomly:

If you roll an effect you’ve already rolled, it spills over to another effect on the same row. If all effects on the row are filled, then the effect rolls down to the next level of the pyramid.

While it’s possible for your ship to suffer catastrophic damage the very first time you’re hit in combat (Abandon Ship!), there is one glimmer of hope: On a roll of 00, you still suffer the megadamage, but it has no further effect.

Variant – Fast Escalation: If you roll an effect your ship is already suffering from, you instead sink down the pyramid to one of the two adjacent damage effects (determine which one randomly).

Most RPGs use turn-based combat because it can provide a simple method for clearly resolving the chaotic realities of the battlefield. (Simultaneous action resolution, for example, can work really well with very small numbers of combatants, but then breaks down rapidly as the number of combatants increases.)

Turn-based combat, however, creates mechanical oddities: If you were in a swordfight with someone and they were like, “Hang on a sec. I’m just going to grab a pint and have a quick drink,” you’d just stab their dumb ass. But because we’re using an abstract mechanical structure in which everyone resolves their actions one at a time — even though, in reality, everything is happening simultaneously — suddenly you’re just supposed to stand there watching me take my drink because it’s not your turn.

To deal with this, we add off-turn mechanics that allow characters to react to things that they should, logically, be able to react to, even if it isn’t their turn. In D&D 5^th Edition, these mechanics include the Ready action, reactions, and opportunity attacks.

We can add one more level to this by adding mechanics that allow you to, for example, avoid opportunity attacks. We might want to do this because a character is super-skilled at drinking in the middle of combat, or maybe just because it’s a bad-ass moment. (The Disengage action in D&D 5^th Edition is technically one example of this. In D&D 3^rd Edition you could make Tumbling checks to avoid attacks of opportunity from movement and Concentration checks to avoid provoking while casting a spell.)

D&D 3^rd Edition sought to implement a lot of mechanics from previous editions of the game in ways that were both more consistent and comprehensive. This included inventing the term “attacks of opportunity” and classifying which actions would “provoke an attack of opportunity.” This made sense, but in practice it had a major drawback: It created a huge list that filled nearly two full pages of actions detailing which actions did (and did not) trigger attacks of opportunity, and you either had to reference that list constantly during play or you had to memorize it. Even if most of this list boiled down to common sense, the result was still Byzantine and arcane.

As a result, after 3^rd Edition, there was a practical impulse to avoid this “grand and unwieldy list” of actions. In D&D 5^th Edition, this simplification has been taken to an extreme: An opportunity attack is triggered only when a combatant you can see moves out of your reach, unless they take the Disengage action.

This eliminates the complexity of the list by boiling the mechanic down to a single trigger, but it allows a lot of immersion-breaking shenanigans on the battlefield. And even the implementation of the movement-based trigger is kinda wonky: You can literally run circles around an opponent while firing arrows at someone on the opposite side of the battlefield, but you can’t walk past them while swinging your sword at them. And, bizarrely, this means that creatures with longer reach are actually less effective at attacking people around them.

In my opinion, if you wanted to simplify opportunity attacks, it would be preferable to either (a) eliminate the mechanic entirely (can’t get simpler that that!); or (b) go the other direction.

HARDCORE OPPORTUNITY ATTACKS

By default, any action you take provokes an opportunity attack from any combatant who can reach you.

There are three exceptions:

• Any attack action
• Dodge
• Disengage

In addition, Ready doesn’t provoke, but the action you’re readying may provoke when you take it.

Bonus actions, reactions (other than readied actions), and your free object interaction never provoke opportunity attacks.

Movement provokes opportunity attacks normally.

OPTION: BETTER MOVEMENT OAs

When using this option, movement provokes an opportunity attack whenever a character moves more than 5 ft. within your reach on their turn or moves out of your reach.

Note: Disengage still cancels all movement-based opportunity attacks during your turn. You also don’t provoke an opportunity attack when you teleport or when someone or something moves you without using your movement, action, or reaction.

OPTION: DAMAGE SPELLS

Spellcasters can use their bonus action to avoid the opportunity attack triggered by casting a spell if the spell deals damage.

Note: This rule may be useful to make some 5^th Edition spells work properly. It avoids needing to make all of those spells special case exceptions. Our goal remains One Rule to Rule Them All.

OPTION: HARDCORE RANGED ATTACKS

Using this option, only melee attack actions avoid opportunity attacks. Ranged attacks still provoke.

Note: As with a spellcaster, you might allow a ranged attacker to use their bonus action to negate the opportunity attack.

DESIGN NOTES

Positioning in combat should matter. You want your rogue to pick the lock on the door so you can all escape? Cover their back! You want your spellcaster to rain hellfire down on your foes? Form a defensive line and give them the space they need to do it.

By allowing characters to just do whatever wherever, the 5^th Edition opportunity attack rules cheapen positioning.

Beyond making the battlefield a more interesting space for tactical challenges, I also want things to make sense: If you’re going to do something that isn’t directly focused on fighting, I want you to think to yourself, “Should I really be doing this where the guy with the pointy metal can stab me?”

At the same time, we want to avoid a bunch of Byzantine complexity. We don’t want a big list of what does and does not trigger an opportunity attack: What we want is a simple, straightforward rule that we can easily memorize and apply. We want One Rule to Rule Them All. By flipping things around and listing the very small list of things that DON’T provoke, we achieve that goal.

From a practical point of view, if we end up in a situation where this One Rule to Rule Them All doesn’t make sense, it’s much easier for me as a DM for me to “break” the rules with a ruling that’s more permissive to the PCs than one that isn’t. In other words, saying, “Actually, it would make a lot of sense if this thing you’re doing that would normally provoke doesn’t provoke in this situation,” the players will be much happier accepting that than if I have to say, “Actually, this thing you thought wouldn’t be bad for you is actually going to be bad for you.” A restrictive framing, therefore, can paradoxically give us a greater liberty to make bespoke rulings when and if they’re needed.

ADVANCED DESIGN NOTES

Taking a step back from opportunity attacks, there are two different broad approaches to modeling the idea that you can’t just run willy-nilly around a battlefield or do a crocheting project in the middle of a melee without consequences.

First, you can try to mechanically enforce it: Thou shalt not.

Thou shalt not move past someone threatening you with a melee weapon. Thou shalt not drink a potion if someone has marked you as their target. Thou shalt not run through an area under the effects of suppressive fire.

(My house rules for combat in 1974 D&D, where the procedure effectively makes melee “sticky,” is another approach to this.)

You can also mitigate this approach: Thou shalt not X, unless Y.

For example: “You can move through a threatened space if you succeed on an Acrobatics check.” Or, “If you get hit with an opportunity attack, you have to stop moving.” (If you can avoid the attack, then you can ignore the Thou Shalt Not.)

The other approach is that you can impose a cost for doing it — e.g., “You can do X, but you’ll suffer a penalty.” Or risk getting hit by an extra attack. Or lose an action.

This approach gives more flexibility: If you really want or need to do something, you can still do it. You just have to pay the cost.

And, once again, you can add conditionals that allow characters to mitigate or entirely avoid these costs.

Of course, the higher the cost becomes, the greater your need or desire would need to be to endure it. Conversely, the more negligible the cost becomes, the less influence it will have over the characters’ decisions.

If you think about opportunity attacks within this design paradigm, 5^th Edition’s opportunity attacks are clearly aiming for the second method, and my argument is that they have become so trivial that you would be better off either (a) eliminating them entirely in order to streamline combat and encourage even more movement on the battlefield or (b) using the hardcore opportunity attacks house rules (or something like them) to make them actually matter.

Alternatively, you could abandon that paradigm entirely and maybe try to implement something of the Thou Shalt Not variety.

“If I cast a fireball spell and fill a room with a giant explosion that incinerates a half goblins, shouldn’t the curtain in the room catch on fire? And how did the delicate potion bottles the goblins were carrying all manage to survive the explosion?”

“If I fell into a vat of acid… even if I survive, isn’t there a risk that my boots of elvenkind would be damaged?”

“So if I stabbed him through the chest, which is mithril shirt in perfect condition and ready to be worn into combat?”

Good questions!

Questions like this have been asked since at least the dawn of D&D (and I wouldn’t be shocked if they date back to Arneson’s Blackmoor campaign), so by asking these questions you’re part of a tradition that’s entering its sixth decade!

And, traditionally speaking, there are several broad approaches that have been taken to answering this question:

1. Let’s just ignore that sort of thing. It’s not worth the hassle.
2. The GM can just apply that sort of thing ad hoc when it seems appropriate. (GM intrusions are a great mechanic for handling this!)
3. Whenever we cast a fireball or someone gets hit by a black dragon’s acid attack, we should (a) resolve the attack and then (b) have some sort of procedure for applying (or potentially applying) damage to every single individual piece of equipment carried by the character, tracking the hit points for each individual piece of equipment. It probably makes sense to have a threshold of damage at which the item’s utility is impaired and then another at which it’s totally destroyed. Oh! We’ll also need repair rules, so that damaged equipment can be recovered before it’s lost forever!

The great thing is that anyone actually doing #3 inevitably discovers that it’s a huge pain in the ass and they rapidly circle back to #1. So it turns out there’s really only one solution, it’s just a question of how long it takes for you to reach it!

… but there are a couple things to think about.

First, it turns out that “you can cast fireball or meteor swarm and unleash overwhelming hellfire upon your enemies, but if you do that you risk losing all the kewl lootz they’re carrying” was actually an interesting balancing mechanic that varied gameplay and created interesting strategic choices.

Second, the verisimilitude of “your acid arrow melts a hole through the goblin’s chain armor!” or “as the flames of fireball clear, you can see that all the books in the library are aflame!” is appealing. It just makes sense! That’s why, after five decades, we’re still asking these questions!

Plus, it can really make the wizard’s player feel like a badass.

Is there a way we can have the best of both worlds?

Maybe.

LOOT DAMAGE!

When looting an NPC’s corpse, roll 1d6 for each:

• Armor
• Weapon
• Magic Item (or other significant item)
• Container (e.g., a backpack)

On a roll of 1, the item was damaged. (Their armor is rent; their blade broken; the potion bottle shattered.) If a container is indicated, the container is ruined and you should additionally make a check for each item bundle in that container.

Non-Fragile Magic Items have advantage on this check. (Roll 2d6, and both dice must roll 1 for the item to be destroyed.)

Fragile Items or items that are particularly vulnerable to the attack(s) suffered (e.g., paper blasted by a fireball) have disadvantage on this check. (Roll 2d6, and a 1 on either die means the item has been destroyed.)

Area Effects, like a fireball or dragon’s acid breath, trigger a check for all unattended loot in the room / area of effect. You can wait until the PCs start looting to make these checks, but a check is made for each area damage effect! (If there are valuables about, use with caution!)

DESIGN NOTES

The advantage of a loot-focused approach is that the bookkeeping is pushed to the point where the party is, in fact, looting the bodies. Listing, distributing, and recording loot is, of course, already a moment in the session that’s focused on bookkeeping. So rather than bogging down the action-focused combat sequences, this system.

By using a simple binary check (destroyed or not destroyed?), we’re also simplifying the mechanic so that it can be resolved quickly and efficiently. Simply grab a fistful of d6s, roll them all at once, and check the condition of each item as you list it for the players.

You can easily tweak this procedure by varying the dice size until you’ve got a frequency of loot damage that feels right to you.

GRITTY VARIANT: PC EQUIPMENT

In addition to checking for loot damage, when a PC is slain or brought to death’s door, make a damage check for their equipment (as per the loot check).

These checks might be triggered only if a PC is actually killed. (“We were able to raise you from the dead, Norgara, but not your plate armor.”) Alternative thresholds might vary depending on what edition of D&D you’re playing, and in some cases you might have multiple triggering events:

• D&D 5^th Edition: When the PC has to start making death saves.
• D&D 3^rd Edition: The PC has negative hit points, even if they haven’t reach their death threshold.
• D&D 3^rd Edition: The PC suffers massive damage.
• AD&D: The PC is reduced to 1/10^th their maximum hit points.

For a truly brutal variant in any edition, you could also trigger an equipment damage check any time the character fails a saving throw against an area effect. (Or, for a less painful version, when they roll a natural 1 on a saving throw.)

DESIGN NOTES

In D&D 5^th Edition, in particular, triggering an equipment damage check on death saves gives them an extra bite. You REALLY don’t want to be popping up and down on the battlefield! Get some healing to your allies!

INCIDENTAL DAMAGE

Incidental environmental effects and damage — e.g., curtains being set on fire, windows being blown out, spilled oil being set aflame — is still be handled via GM fiat and the whim of description.

If you want a rudimentary procedural generator for this, however, you could roll an additional 1d6 for each area effect and, on a roll of 1, make a point of including a significant environmental effect (e.g., the dragon’s acid breath melts the floor, creating difficult terrain; or the fireball spell causes the barrels of oil in the room to explode).

ADDITIONAL READING
Shields Shall Be Splintered!
5E Encumbrance by Stone

Disclaimer: I am not entirely sure how serious I am about this.