Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

Using the fatigue rules was exactly what I thought when I saw the OP's question. It's how I'd do it.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

Well perfect conversions are usually exercises in frustration. But for covering that, especially thigs that generated more heat you can add more Costs FP.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

Why are we trying to build vehicles as characters, here?

I'd go for a relatively direct port, probably. Mechs are vehicles, and they have an additional meter for heat accumulation. You can have them gain and lose heat exactly the same ways as in the source material, and translate over the consequences of high heat. (Reduced Handling, rolls against modified HT to not explode, etc.)

It doesn't seem hard to do that in a generally faithful way.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

I'm almost sure I remember some of the mechs on the tabletop having some beneficial heat effects, though I also know think I remember that being dark age stuff and I don't need to worry about anything that far down the timeline.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

Going with 60 second or 1 second turns is another thing I'm trying to decide on. I mean, it won't be to unusual for infantry and elementals (Clan power armored genetically modified super infantry) to be running around the battlefield, and also going purely by the lore established by the novels mech a surprisingly (Impossibly) nimble and agile for their size and pilots consistently maneuver and react to things split second.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

Mech hand-to-hand combat is a significant setting element. First-person real-time mech piloting games are one of the more prominent elements of the franchise. Mech combat seems no less well suited to second-by-second resolution than personal combat.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

Ya, I think that's what I'm gonna go with.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

So I'm thinking a thermal point system where all heat building weapons have a TP score and that's how many TP they generate when firing, heat transferring weapons also build TP when used against any mech they hit. How fast a mech bleeds TP will depend on amount of heat sinks in the mech. When Mechs reach a designated TP threshold they make an HT roll every time they gain more heat, with failure causing overheating effects. At twice the threshold the HT roll is at -2, overheating effects more severe, and the computer starts blasting warnings. At three times rolls are at -4, effects extremely severe, and automatic shutdown has to be manually overridden. At four times the threshold the rolls at -6, any additional heat build up requires more rolls, the overheating effect are crippling, and any critical failure will cause the reactor to begin meltdown and the emergency containment protocols to go off leaving the mech none functional until repair, on an 18 the reactor will just blow up.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

One thing this thread has made clear is that Vehicles 3e (4e?) should include thermal management. It isn't just Battletech, every modern vehicle has and needs a cooling system - easiest way to take out a car is put a bullet through the radiator, and modern spacecraft have massive heat issues.

Re: GURPS BattleTech, working out heatsinks and the effects of heat buildup
 

Short answer:
Use BattleTech for the basic mechanics. Swap the signs of the penalties and just use GURPS characters. It works. Been doing it that way for years.

Beyond that, take a look at MechWarrior: Destiny for some inspiration.
Divide heat sinks by, say 5.
Divide weapon heat by, say 3.
Take every 4th entry on the Heat table.

It'll make heat more manageable, and more interesting for a game.