Mecha in Tunnels & Trolls

After rolling up some Heroes Unlimited characters and easily converting them to Mercenary’s, Spies, and Private Eyes, I wondered if the Tunnels & Trolls engine would handle Mecha. At first I thought that given that attributes had no limit in T&T, that I could just run Mecha as characters. That may be true, but as I worked towards an initial prototype I departed from that somewhat. I had originally wanted to convert Rifts mecha to T&T, but the 3025 BattleTech lineup is the gold standard in mech concepts. While adapting those mecha, I wanted to convert missiles to be one shot weapons as well in order to better match the original source material. Here is the first pass at these rules after testing it with a battle with an Atlas and an Orion going against a Stalker and a Thunderbolt.

Stat conversions:

Constitution aka Hit Points are equal to BattleTech tonnage

Armor aka Damage Resistance is equal to BattleTech armor factor / 10 and rounded down.

Luck aka Dodge is equal to 7 + BattleTech walking MP’s

Speed aka Move is equal to 5 + BattleTech walking MP’s

Melee Dice = BattleTech tonnage / 10 rounded up (never used this in anger)

SRM’s are single shot and are rated at 2 dice per missile port. They can fire at Point Blank or Close range which is up to one range band away.

LRM’s are single shot and are rated at 1 die per missile port. They can fire at Far or Extreme range, which is two or three range bands away.

Weapons that have a range of 9 in BattleTech can fire at Point Blank or Close Range. They get half their dice in damage rounded down.

Large Lasers can barely fire at Far range. PPC’s would be solid at Far range. Some autocannon will fire at Far range. Give half their damage in dice here, but less for the large lasers which aren’t as good. These weapons can also fire at Close range.

The movement system is very abstract. It comes from the Classic Traveller range band system. The idea was that the chaos and unpredictability of combat would lead to Players declare whether a mech will advance or retreat or stand their ground. Moving mech making a saving roll against their speed attribute. That is, they roll 2s6 with doubles adding and roll over. If the speed attribute plus the die total is greater than or equal to 20, THEN the mecha actually performs its movement. (This creates some interesting situations and feels true to the action even though it may appear to be complete nonsense as an idea.)

Movement actions are declared secretly and simultaneously and then resolved publicly.

After that fire actions are declared secretly and simultaneously.

To-hit targets are 6+ for near, 8+ for far, and 10+ for extreme. To check for to-hit, roll 2d6 with doubles adding and then rolling over. If the total is greater than or equal to the target, then it’s a hit. Special note: each double that is rolled in the to-hit adds a -1 to the target’s dodge roll as does each increment of 5 that the roll is exceeded.

For hits, check to see if the target dodged. This is a saving roll against the mech’s Luck stat. Success means the hit is converted into a miss.

Total the damage done to a mech in a round and subtract the mech’s armor stat from it. This is the amount of points deducted from the mech’s constitution.

If a mech takes 25% or more in damage in one turn, it takes a -1 penalty to its speed saving roll the next turn. If it takes 50% or more in damage in one turn, it will take a -2 penalty instead. (Mechs that take a bunch of damage are more liable to get pinned down and finished off.)

In this first pass conversion, the game is mostly about what happens with the missiles. So much is at stake! After they are all fired it should be obvious who is winning. Note that these base numbers here are VERY stingy and bonuses for good piloting or good gunnery in the +1 to +4 range would be very reasonable.

To view the log of the first playtest, see this thread.

Playtester comments:

“I like the roll to activate movement here. It makes the big guys feel heavy.”

“Missiles being single shot is def more in keeping with the visual inspiration”

“I very much like it for quick solo games or over discord resolutions…. It’s quite slick.  I would highly recommend.” — Boldvay

I did not necessarily like leaving the vanilla combat system, but Tunnels & Trolls seemed to lack a coherent set of movement rules as far as I could tell. Having a High Guard type abstraction level beyond the PC scale seems to make sense. Though maybe if I drop the commitment to recreating BattleTech I could work something else out. Building on what we have here, a strategic game where two sides attempt to kill the other’s command post is the next logical step– deployed mech would have to return to their cp to get their missiles reloaded.