Burning oil as a weapon

[harlandski]

As far as I know the only description of burning oil in the 3lbbs is from vol. 3 ”Burning oil will deter many monsters from continuing pursuit."

I'm about to run my first OD&D game for my friends, using the lbbs, and the thief class from Greyhawk. I can see my players wanting to use oil as a weapon (as described in Holmes).

I'm not sure if there were any canon statements about weaponized burning oil before Holmes, if so I'd be interested to hear. Otherwise, it would be great to know how this was managed back in the day, or how folk rule it in their games today.

Would lamp oil even ignite if spread on a person, I wonder? (Don't try this one at home, kids...)

[waysoftheearth]

IMC lantern oil is just fuel. Weapon-grade, explosively inflammable oil costs 20 gp rather than 2 gp.

[harlandski]

Jan 1, 2019 23:47:58 GMT -6 waysoftheearth said:

IMC lantern oil is just fuel. Weapon-grade, explosively inflammable oil costs 20 gp rather than 2 gp.

I see. And how would you rule damage for the expensive kind?

[waysoftheearth]

I use one damage die (1--6) on first impact, and a second die on the subsequent turn if the target doesn't somehow smother the flames, jump in a lake, or similar.

[howandwhy99]

Where does oil come from in your game? What are its stats?

IMC using burning oil is a learning process. Damage amounts depend on multiple factors, but is from Normal Fire. And the damage baseline for one flask of normal oil is 1d6/minute for 2 minutes. Of course other materials can burn as well, longer even. Flesh?

Contemporary lamp oil is not necessarily what D&D oil is.

[gemini476]

If you're curious (or just want a quick reference), here's how flaming oil was handled in Chainmail and AD&D. Paraphrasing for brevity and copyright.

In Chainmail, burning oil comes up in the context of a pot of it being poured down a castle wall onto intruders. It goes down a 2" section of wall, killing those within it, and turns into a 4" wide 3" deep puddle at the bottom that also kills anyone within it. It then burns for three turns, preventing passage, and will also set alight wooden structures over the course of five turns (but not ladders, perhaps for balance reasons).
This is not directly applicable to OD&D, what with the difference in scale, but perhaps it can serve as inspiration. If nothing else, "it burns for three turns" might be a handy guideline (even if a Chainmail turn is but one minute).

In AD&D's DMG (it probably came up elsewhere, but this is what I have), flaming oil comes up in the GRENADE-LIKE MISSILES section (p.64-65 in my copy). Those directly hit by the hurled flask take 2d6 damage the first round, 1d6 the next, and those within 3' of the target take 1hp/segment for 1d3 segments. (Presumably that's to let the poor kobolds perhaps get a hit in first?)
The description is particularly handy, as it gives a good idea of what "a flask of oil" was in the writer's mind:

If oil has been specially prepared by insertion of a rag into the opening of the container (or wrapped around the neck of the container) and set afire prior to hurling, it will burst into flame when the container breaks upon target impact; otherwise, a torch or other means of causing combustion must by brought into contact with the oil.

In other words, they wrote "flask of oil" but thought "molotov cocktail". This probably explains the discrepancies - historical lamp oil is a lot less flammable than petrol, turpentine, or kerosene!

Also in AD&D is, finally, "Crossing Flaming Oil". Leaping over doesn't cause damage (unless you're "highly inflammable"), although if you're wearing cloth you need to roll on the item saving throw tables lest it catches fire. Walking through or standing in it does 1d6 damage/round.
To save you the trouble, the saving throw of Cloth vs. Normal Fire is "roll less than 13". (The table is reversed from the norm, although the text doesn't seem to realize that - magic items get +2 to saves despite that seemingly making it worse, liquid gets -10 on the die if frozen and smashed despite that making it less likely to break, etc.)


So putting that together, here's an on-the-spot ruling: burning oil burns for three rounds, causes 1d6 damage per round you're in it, and most monsters tend to not want to burn themselves. Don't worry about the anachronisms.

[waysoftheearth]

The main use of burning oil described in U&WA (p12) is to deter pursuit (which aligns with gemini's comment re: monsters not wanting to cross burning oil).


The other items that can deter pursuit are food and treasure. Food (for dungeon expeditions) costs 15 gp, so it makes some sense that another item that can serve the same function might have roughly the same cost. That burning oil can second as a weapon is a "bonus". Similarly, the bonus function of food is that you can safely eat it

[harlandski]

Jan 2, 2019 16:37:08 GMT -6 gemini476 said:

If you're curious (or just want a quick reference), here's how flaming oil was handled in Chainmail and AD&D. Paraphrasing for brevity and copyright.

In Chainmail, burning oil comes up in the context of a pot of it being poured down a castle wall onto intruders. It goes down a 2" section of wall, killing those within it, and turns into a 4" wide 3" deep puddle at the bottom that also kills anyone within it. It then burns for three turns, preventing passage, and will also set alight wooden structures over the course of five turns (but not ladders, perhaps for balance reasons).
This is not directly applicable to OD&D, what with the difference in scale, but perhaps it can serve as inspiration. If nothing else, "it burns for three turns" might be a handy guideline (even if a Chainmail turn is but one minute).

In AD&D's DMG (it probably came up elsewhere, but this is what I have), flaming oil comes up in the GRENADE-LIKE MISSILES section (p.64-65 in my copy). Those directly hit by the hurled flask take 2d6 damage the first round, 1d6 the next, and those within 3' of the target take 1hp/segment for 1d3 segments. (Presumably that's to let the poor kobolds perhaps get a hit in first?)
The description is particularly handy, as it gives a good idea of what "a flask of oil" was in the writer's mind:

If oil has been specially prepared by insertion of a rag into the opening of the container (or wrapped around the neck of the container) and set afire prior to hurling, it will burst into flame when the container breaks upon target impact; otherwise, a torch or other means of causing combustion must by brought into contact with the oil.

In other words, they wrote "flask of oil" but thought "molotov cocktail". This probably explains the discrepancies - historical lamp oil is a lot less flammable than petrol, turpentine, or kerosene!

Also in AD&D is, finally, "Crossing Flaming Oil". Leaping over doesn't cause damage (unless you're "highly inflammable"), although if you're wearing cloth you need to roll on the item saving throw tables lest it catches fire. Walking through or standing in it does 1d6 damage/round.
To save you the trouble, the saving throw of Cloth vs. Normal Fire is "roll less than 13". (The table is reversed from the norm, although the text doesn't seem to realize that - magic items get +2 to saves despite that seemingly making it worse, liquid gets -10 on the die if frozen and smashed despite that making it less likely to break, etc.)


So putting that together, here's an on-the-spot ruling: burning oil burns for three rounds, causes 1d6 damage per round you're in it, and most monsters tend to not want to burn themselves. Don't worry about the anachronisms.

I also looked at the Chainmail reference, but decided it's a completely different thing (heating up cauldrons of oil to tip down onto people trying to scale castle walls). I'm trying not to look at AD&D at the moment, but to stick within the logic and scale of OD&D*, though it is interesting to see how Gygax ended up ruling this.

*For this reason I like waysoftheearth 's ruling as it "feels" like a good fit with OD&D power levels.

[aldarron]

Jan 2, 2019 16:37:08 GMT -6 gemini476 said:

historical lamp oil is a lot less flammable than petrol, turpentine, or kerosene!

Interesting, but I'm not sure where you are sourcing that information. I'll grant you petrol and maybe turpentine, but lamp oil (it's the same today as "historically") is a kerosene (liquid paraffin) refined to remove impurities that cause smokiness. I've never heard, and a quick search did not reveal, any indication that flammability was affected. In other words, as far as I know, lamp oil and standard kerosene are equally flammable, because they are basically identical. If you have some different info on that it would be interesting to know.

[Zenopus]

Jan 1, 2019 23:07:05 GMT -6 harlandski said:

I'm not sure if there were any canon statements about weaponized burning oil before Holmes, if so I'd be interested to hear. Otherwise, it would be great to know how this was managed back in the day, or how folk rule it in their games today.

Correct, Holmes Basic is where the rules for oil as a thrown weapon were first added to D&D. And FWIW, Holmes did not put these in himself; the manuscript just has a brief paragraph about pouring it out on the floor and lighting it. Someone at TSR, most likely Gygax, added the longer section on using it as a thrown weapon. It's one of the longest sections added to the Holmes Rulebook that was not in the Holmes Manuscript; most often Gygax just added a clarifying sentence or two at the end of what Holmes wrote. And these oil rules seem to prefigure the even longer rules found in the AD&D DMG. For more details, see Part 14 of the Holmes Manuscript series.

Delta had several interesting posts on burning oil:

deltasdnd.blogspot.com/2011/09/on-burning-oil.html
deltasdnd.blogspot.com/2012/01/on-burning-oil-part-2.html
deltasdnd.blogspot.com/2014/02/more-burning-oil.html
deltasdnd.blogspot.com/2014/09/on-burning-oil-part-3.html

[gemini476]

Jan 3, 2019 10:29:52 GMT -6 aldarron said:

Jan 2, 2019 16:37:08 GMT -6 gemini476 said:

historical lamp oil is a lot less flammable than petrol, turpentine, or kerosene!

Interesting, but I'm not sure where you are sourcing that information. I'll grant you petrol and maybe turpentine, but lamp oil (it's the same today as "historically") is a kerosene (liquid paraffin) refined to remove impurities that cause smokiness. I've never heard, and a quick search did not reveal, any indication that flammability was affected. In other words, as far as I know, lamp oil and standard kerosene are equally flammable, because they are basically identical. If you have some different info on that it would be interesting to know.

I thought medieval lamp oil was mostly vegetable oil? Note the difference in flash point between kerosene (100–162 °F) and canola oil (621 °F).

Then again, there's a big difference between medieval lamps and medieval lanterns: the latter tended to have candles inside, meaning that OD&D's "Flask of Oil" is probably intended for something more akin to an anachronistic kerosene lamp. There's a Gygax quote in those Delta's D&D Blog entries about how OD&D's lamp oil is kerosene, but I don't know how accurate those are to the events of the '70s.

The lighting systems are largely nonsense, in any case (torches are ill suited for underground use due to smoke, oil lamps and lanterns don't light up much), so it's really just Hollywood rules.

[retrorob]

In my current campaign I use 1d6 damage, one has to roll vs AC 9 (adjusting for Dexterity), only one target affected. Animals (including "giant" ones) will flee when hit by burning oil. Previously though I treated oil as fuel for lantern only, but there was also a Molotov cocktail: 2d6 damage (cost 200 GP).

[harlandski]

Jan 4, 2019 8:51:38 GMT -6 retrorob said:

In my current campaign I use 1d6 damage, one has to roll vs AC 9 (adjusting for Dexterity), only one target affected. Animals (including "giant" ones) will flee when hit by burning oil. Previously though I treated oil as fuel for lantern only, but there was also a Molotov cocktail: 2d6 damage (cost 200 GP).

So I refereed OD&D with a group of players for the first time today, and I came up against the question of armor class for holy water (which I'm taking as analogous to oil against undead). I like the idea of using AC9 as armor wouldn't really protect well against a liquid. I also like the distinction you make between regular vs weapons-grade oil in terms of damage, as I think some creative use of the regular oil on the equipment table should be encouraged.

[aldarron]

Jan 4, 2019 6:41:35 GMT -6 gemini476 said:

I thought medieval lamp oil was mostly vegetable oil?

Oh I see your confusion.

Well, there is no such thing as "medieval lamp oil". "Lamp oil" is, as I mentioned a specialty paraffin product. In the middle ages and earlier, people burned all kinds of different oils in lamps, like olive oil for example, but there was no special oil just for lamps. People used whatever oil they had for whatever they needed oil for. Actually, turpentine was used in lamps in some places, and even a crude form of kerosene had been developed and was known to a few. But yeah, most people in most places burned the same oil they ate on their salads or treated rusty hinges with.

Keep in mind that OD&D is a fantasy game with plenty of anachronisms (and even sci-fi elements), like mirrors and kerosene burning hurricane lanterns. "lamp oil" in OD&D was always meant to be actual lamp oil - the kind you buy in the hardware store.

I realize this seems to be coming as news to you and you might be a bit skeptical, but you don't need to take my word for it. Gygax mentioned this a few times. One quote of his I like to point to used to be archived on enworld but things there have been moved around so that I can't link to it, but here it is anyway "In OD&D the 1st level PCs did do several things to help extend their chnaces--hire men-at-arms, use missile weapons (including flaming lamp oil, that is kerosene), and run away when things appeared to be too dangerous to stay and fight."