3d6 D&D ... or D&D Neat?

Has anyone written rules for D&D with just 3d6? I have a recurring curiosity to write rules just using regular dice, mostly in case I get stuck somewhere like somebody's cabin in the woods, and I want to play D&D, but the only dice to be found are in a Monopoly or Yahtze game ...

You could call it D&D Neat--like neat wine or liquor (i.e. not mixed with anything, not even water), it would be D&D with neat dice, just d6s unmixed with anything else.

My initial thought was to roll attacks as a "roll under" mechanic, i.e. STR 13, roll 3d6, 13 or lower on the dice is a hit (then roll a d6 for damage like OD&D). But that gets probabilistically weird outside the range of 9-12 STR/DEX, and makes a fighter with STR 18 unstoppable ...

Current thought is to assign an attack value starting from 11, adding STR, level, and magic bonuses to the value (i.e. fighter 4, STR 13, +1 sword has attack value 14). Roll equal to or under your attack value to hit.

Armor class could be ascending, 1 (shield or leather), 2 (shield and leather or mail), 3 (shield and mail or plate), 4 (shield and plate), add your opponent's armor class to your roll (roll a 12 on the dice attacking a fighter in plate, actual roll 15; attack roll 15 > attack value 14 = miss!).

I've done a very small amount of testing, and this latter system seems to work decently for first level play ... I'm curious about the probabilities, but not patient enough to do the math.

(Yeah, I realize I could dig up Chainmail attack tables or something, I understand they use a mere pair of dice ... but this is supposed to be a way to play D&D with fewer accouterments, not a substitution of some other chart! On the same point, I have separately created a 111-666 table that somewhat mimics the probabilities of a d20 roll, i.e. approximately 5% per entry--but again, that requires a whole chart instead of some simple arbitrary values)



And I haven't even touched Saves yet (or anything else, really) ... though I imagined assigning them arbitrary values kind of like attack values, maybe inspired by the B/X charts.

Or maybe just roll under a relevant stat.

Anyway, this is a vanity project like I said, a thought experiment as to how I'd run D&D in desperate circumstances (with only six-sided dice--or worse, a single die!)