Tag Archives: vehicles

MBT Viability in Twilight: 2000 4e, Part 2

Continuing from the original post here, based on the Juhlin.com forum thread here. I realized I’d never recorded my follow-up thoughts on the blog. Let’s rectify that.


Twilight: 2000 in all its editions is much more post-apoc adventure survival fantasy than excruciatingly-accurate simulation (Apotheosis Saga, anyone?). So treads and lube aren’t usually tracked to the level of tank extinction. But let’s talk about the mechanics of mechanical issues for our hypothetical T-72 owners.

Maintenance

v2

A T-72 requires 14 hours of maintenance per week. Potential breakdowns occur every 8 hours of movement or combat, rolled against the vehicle’s Wear value (10% for like-new, to 100% if it’s on its last legs). If there’s potential for a breakdown, the mechanic who did the last maintenance rolls a Difficult Mechanic check to see if his work prevented the breakdown.

Assuming a well-optimized but not maxed mechanic PC (Strength 8, Mechanic 8), a Difficult Mechanic check has an 80% chance of success.

v4

Every vehicle requires the same amount of maintenance: 6 hours per week in which it was driven at least one hex on the overland map. Maintenance requires a successful Tech roll. Failure reduces Reliability by 1 (with most vehicles maxing out at Reliability 5, so you have some margin for error).

Assuming a well-optimized but not maxed Mechanic PC (Intelligence d10, Tech d10), a Tech roll has a 75% chance of success.

Parts and Repair

v2

A well-buried rule indicates that parts need to come from a vehicle identical to the one being repaired. Furthermore, there’s some text indicating that parts are also component-specific (engine, main gun, radio, etc.). There are no explicit rules for scrounging or buying parts.

No roll is required to cannibalize a donor vehicle’s component for parts. However, if the component is damaged, there’s a 30% chance that the part is useless.

A character who’s a capable machinist (or gunsmith, for ordnance repair) may also fabricate mechanical parts with a successful skill check andaccess to a machine shop.

Most repairs require 1d10 parts (1d5 for minor breakdowns).

Damage is tracked by vehicle component, with most components having two states: OK or inoperable/destroyed. A few have an intermediate damaged-but-still-partially-functional state.

v4

“Vehicle parts” are generic – when needed, a bolt, brake cable, or turbocharger materializes out of the quantum foam of your mechanic’s spares box.

A successful Tech roll when scavenging a vehicle yields one part per success rolled, -1 for a destroyed vehicle. Parts are considered to be “common,” which means a 67% chance of availability in a typical settlement.

Only one part is needed to repair a destroyed item, though each repair only restores 1 Reliability per success, so thorough work will likely consume more than one part. Restoring reduced Reliability on an item that wasn’t fully destroyed doesn’t consume any parts.

A vehicle’s Reliability score covers its overall structural integrity, its transmission, and its engine. Weapons, radios, and other subsystems either have their own Reliability tracks or have OK/inoperable states.

Ammunition

v2

2nd edition provides varying availability levels for different ammo types.

125mm HE is common (80% chance of being available in cities, 70% in towns, 30% in villages).

125mm HEAT is scarce (60% in cities, 40% in towns, 20% in villages).

125mm sabot is rare (20% in cities, 10% in towns).

12.7mm and 7.62x54mm for the MGs are both common.

v4

As a broad category, all non-guided heavy weapon ammo is scarce (33% chance of availability in any settlement).

All small arms ammo is common (67% chance of availability in any settlement).

In both cases, chance of availability is for the broad category of item. The referee decides whether a specific sought-after model/type/caliber from that category is available. The West Possum Trot Trading Post may be fresh out of 125mm HEAT, but surely 122mm howitzer mustard agent shells are close enough for government work, right?

(Really, that last paragraph captures it. Ammo availability, perhaps more than any other resource, will be subject to referee judgement and fiat, even with strict adherence to the framework of the rules.)

To close it out, here’s a price comparison for main gun ammo:

Twilight: 2000 4e Conversion: NM-116

Continuing my fascination with new-to-me Nordic light tanks (see also the Ikv 91), today’s Christmas leftovers offering comes to us from Norway. The NM-116 Panserjager was a Norwegian upgrade of the WWII-vintage M24 Chaffee that served until 1993. Rather than reiterate the excellent Online Tank Museum article, I’ll just link it here. You’re only here for the 4e stats anyway, right?

Because the NM-116 was in real-world service until after the Cold War’s end, we can reasonably assume it would have served in the Twilight War. For those who are using a 1e or 2e alternate history, NM-116s would have been in combat as early as December 1996, when the Soviets made their unsuccessful play for a quick victory in Norway. By mid-2000, surviving examples could have been found anywhere in the Nordic countries. A few might also be floating around the Polish-German coast after being “requisitioned” by American units that fought in Norway and later redeployed across the Baltic (6th Infantry Division and 2nd Marine Division). The sticking point in keeping one operational would be obtaining an ammo supply for the up-gunned 90mm.


Number-crunching on this is pretty basic. Just for fun, I also threw in a stat line for the NM-130, the armored recovery vehicle variant (with all of four built).

If you’re looking for v2/v2.2 stats, Paul Mulcahy, of course, has the NM-116 as a tracked light combat vehicle.

Technically, the coaxial is an M3, but stats should identical to those of the M2HB for game purposes. The 90mm gun is a French low-pressure model (the D/925) also used on some obsolete-by-the-1990s French AFVs. Its ammo selection is limited to HE, HEAT, and smoke, so it’s not going to be punching that far above its weight:


Edited to add: for v2.2 stats, Paul Mulcahy, of course, has you covered.

Twilight: 2000 4e Conversion: Ikv 91

Not having followed the Swedish defense industry in detail (or, really, at all), I had no idea this vehicle existed until a couple of months ago. Now, though, I’m a bit croggled as to why Free League neglected to include it in the vehicle listing for Twilight: 2000‘s fourth edition. To my knowledge, it hasn’t appeared in any previous edition of the game (though, of course, Paul Mulcahy has second edition stats for it).

The Infanterikanonvagn 91 is an amphibious light tank produced in Sweden in the first half of the 1970s, built in low numbers and used only by that nation’s military. It served as a tank destroyer and infantry support gun, with one 12-vehicle company assigned to each Swedish infantry brigade. Primary armament is a 90mm gun, supplemented by coaxial and pintle-mounted GPMGs.

In real-world history, the Ikv 91’s phase-out began in the 1990s. Two variants were proposed: an up-gunned version with a 105mm low-recoil gun, which was prototyped in the early ’80s under the designation Ikv 105, and a TOW ATGM carrier, which doesn’t appear to have progressed past the conceptual stage. Neither made it to production.

In my T2kU, both variants entered production in the late ’80s, spurred by increasing geopolitical instability. The Ikv 105 was intended to replace the Ikv 91, but production numbers never accommodated this, and even those Ikv 91s which had been retired were pulled from reserve stocks to replace combat losses. The ATGM carrier, designated Pvrbv (Pansarvärnsrobotbandvagn) 152, was intended to supplement and eventually replace the existing Pvrbv 551 (itself a TOW carrier built on the chassis of the Ikv 91’s assault gun predecessor).


With no official prior-edition stats1, converting this vehicle is a little trickier than the previous number-crunching I did on the LAV-75 and M88A1. Still, the publicly-available information does provide a basis for conversion while comparing the design to real-world equivalents:

The Ikv 91 and Pvrbv 152 are fully amphibious with no preparation required. The Ikv 105, due to increased weight from the larger gun, can be made amphibious with one stretch of preparations.

I’ve chosen to fit the Pvrbv 152 with the dual TOW II “hammerhead” turret also used on the American M901. The real-world Ikv 91 used the Swedish m/39 machine gun, but standardization on the Ksp 58 seems appropriate for vehicles that are being kept in service in the ’90s. Main weapon ammo load is 59 rounds for the Ikv 91’s 90mm gun, 50 rounds for the Ikv 105’s larger gun, and 10 TOW II AGTMs for the Pvrbv 152.

The 105mm gun and the TOW ATGM already exist in the fourth edition rules, so no conversion is needed. The base 90mm gun looks something like this:

And there we go.


Reference sources used for this post: Wikipedia, Military Today, Tank Nut Dave, Military Factory, Tanks Encyclopedia.


1 I respect Paul Mulcahy and his work immensely, but his stats rarely align with GDW’s baseline work. Also, I use his site only as an error-check or research guide to avoid accusations of plagiarism. In the interest of completeness, I’ll note that in addition to the Ikv 91 traits linked above, he’s also worked up the Ikv 105, which he designates Ikv 93.

Twilight: 2000 4e Conversion: M88A1 ARV

I have an inordinate fondness for a few non-mainstream vehicle types in any variation of Twilight: 2000‘s setting. In particular, armored recovery vehicles and combat engineer vehicles are interesting to me in a way that MBTs and IFVs aren’t. They (generally) can’t withstand the same level of damage that a dedicated combat vehicle can, but they offer some level of crew protection beyond sheetmetal and they carry ancillary equipment that’s useful.

With that in mind, today’s post looks at the M88 armored recovery vehicle – specifically, the M88A1 version that would have been most prevalent in the Twilight War. The original M88 was a fuel hog. The M88A1 received the engine of the M60 MBT, which had lower horsepower but more torque and better fuel economy, as well as upgraded hydraulics for its recovery equipment. The majority of the original M88 production run appears to have been upgraded to the M88A1 standard by 1982, alongside additional new production of the same spec.

(In the second edition timeline – and presumably the first edition as well – the modern M88A2 HERCULES never came to be. Its role instead was filled by the M5 Abrams ARV, as depicted in the American Combat Vehicle Handbook. In our history, the prototype of what might have become the M5 lost a 1987 trial against what was then called the M88A1E1.)

The M88A1’s Twilight War service was fairly broad. Many nations that bought M47s, M48s, or M60s also procured M88s. In American forces, it served with both the Army and the Marine Corps. Most armor units that went to war with M60s included one M88A1 per company (or cavalry troop) maintenance section, as did artillery and ADA batteries equipped with self-propelled guns, mechanized infantry companies, and combat engineer units – basically, any unit with AFVs lighter than Abrams chassis. Additional ARVs were concentrated in maintenance and recovery sections of battalion HQs and higher echelons.

By the end of 1997, commanders had begun to collect their remaining ARVs and other combat engineering and recovery heavy equipment into combined engineering units. Generally considered more valuable in their recovery role than as makeshift AFVs, and ill-equipped for conversion to the troop carriage role, few M88A1s were assigned to front-line combat. All became targets, though, and crews added a variety of improvised armor augmentations and weapon mounts in the hope of increasing their survival rates.


Conversion of the M88A1 is fairly easy, as I can start from the second edition stat block in the ACVH. Modern online sources do list some discrepancies, particularly in the onboard fuel supply, but that’s easy enough for napkin math. Just for the hell of it, I also included M88 traits for that fringe-case CONUS game that digs a non-upgraded original out of a forgotten National Guard armory:

The 4-person crew is composed of commander, driver, mechanic, and rigger. The latter two have no combat roles, effectively being passengers, but each position has its own roof hatch, so they can stand up to fire small arms from partial cover. I’ve been unable to substantiate GDW’s claim that the cabin includes four passenger seats for the crew of a disabled AFV under tow.

Speeds given are for normal movement. The vehicle can tow up to 45 tons at half speed. Two M88A1s in tandem are required to safely tow a vehicle above that weight, such as an M1 Abrams-series MBT.


Beyond the numbers, the M88A1 has four interesting pieces of equipment worth noting for game purposes.

Winch: Front-mounted, 60-meter cable, 41-ton capacity. Treat the winch as a component in the penetrating/cargo hit location with Reliability 5.

Crane: A-frame boom, stowed on top of the vehicle but forward-facing when elevated for work. Can reach up to 2.5 meters in front of the vehicle, with a maximum lift of 7 meters. It’s intended for lighter vehicle recovery (think truck or APC as opposed to MBT) or changing major components (like engines), but can be used for other construction tasks in a pinch. 60-meter cable, 23-ton capacity (drops to 5 tons if the dozer blade is not in use to stabilize the vehicle). Treat the crane as a component in the non-penetrating/external stores hit location with Reliability 4.

Dozer blade: Front-mounted, full width of the hull. Primary designed function is to stabilize the vehicle when winching but can also be used for light earthmoving, including carving out hull-down fighting positions for vehicles. Treat the blade as a component in the non-penetrating/external stores hit location with Reliability 5.

Auxiliary power unit (APU): Can provide limited electrical power without use of the main engine. This enables battery charging (both for the vehicle’s own batteries or other devices), as well as use of the hydraulics that drive the three items described above. Consider this a 5-kilowatt generator (“large” for fourth edition purposes) that consumes 15 liters of fuel per shift (doubled for alcohol, of course). For damage purposes, treat the APU as a component in the penetrating/cargo hit location with Reliability 3.

At the referee’s discretion, appropriate use of appropriate equipment may provide bonuses or reduce the construction time for base facilities. I’d say a fully-functional M88/M88A1 reduces the time for building defensive works from a day per hex to a shift per hex. Most of the other base facilities in the 4e Player’s Manual won’t benefit as much from earthmoving and winching capabilities, but I’d still call it a +1 bonus for anything requiring heavy construction work.

Finally, while few vehicles will have their original TA-50 by 2000, the nominal loadout for an M88A1 includes two sets each of basic and vehicle tools, an assortment of towing and rigging equipment (spare cables, pulleys, hooks, etc.), a couple of portable fire extinguishers, stowage for four 20-liter jerrycans (two water, two engine oil), and 1,500 rounds of belted .50 BMG for the M2.

LAV-75 Viability in Twilight: 2000 4e

Originally posted to the Juhlin.com Twilight: 2000 fan forum.


Having recently discussed the MBT issue in Twilight: 2000’s 4th edition, I thought it might be interesting to tinker with everyone’s favorite apocryphal light tank, the LAV-75. Back in 2009, Kato’s forum had a rather long and productive thread on it, which yielded a few different variants and development histories. I’m too lazy to use that entire thread, but I did cherry-pick the bits dealing with the hypothetical upgrade to a 90mm low-pressure gun system (presumably the same one for which we already have second edition canon stats courtesy of the MPGS-90).

So what does the LAV-75 look like in 4e? Using the conversion rules in the back of the Referee’s Manual, we get a stat line that looks a little something like this (apologies to those on mobile):

(I deviated from canon by providing both pintle and coaxial MGs. Rebellion is a heady drug.)

So, not really awful. It suffers in the tactical mobility department, most notably being slower off-road than the tanks it was intended to slow down in its original RDF conceptualization. However, it’s actually faster on a road march than any of the T-series. But life and AFV design are about compromises.

The big objections to the LAV-75 have always centered around the gun, though. Does it fare any better in 4e rules than it did in previous editions (much less real-world acceptance testing)? Well, let’s take a look at how the 75mm Ares cannon, as well as the 90mm low-pressure gun of the forum’s LAV-75A1, convert to 4e:

(I stuck the 75mm with Reliability 4 because I am cruel. Forgiving referees may feel free to ignore that.)

Okay, so the design objective of both of these guns was to kill Soviet tanks of the types likely to be encountered in Southwest Asia – so anything up to and including a T-72. How do they stack up?

As it turns out, slightly better than in real life. Looking at frontal armor, the T-55 comes in with 6 (actually worse than the LAV-75, by Free League’s own conversion rules), the T-62 has 7, the T-64 goes to 8, and the T-72 goes to 9, while the T-80 (unlikely in the originally-intended AO) goes to 10. For cracking armor, both guns get roughly equal performance (save for range) out of their HEAT and APFSDS rounds. For the 75mm, we’re looking at Damage 6, Armor -1; for the 90mm, it’s Damage 7, Armor -1.

With that Armor -1 modifier, the 75mm will consistently penetrate the frontal armor on a T-55. It won’t automatically crack a T-62 or T-64, but a good hit or luck with ammo dice, because it’s burst-capable may boost the damage enough to go internal. The Penetration Limit rule on p. 82 of the Player’s Manual keeps it from being able to get frontal penetration on a T-72 or T-80. To the sides and rear, of course, good hits are much more feasible, though they still rely on extra successes or ammo dice to pop a T-64 or higher.

How about the 90mm? Much the same story, but up one level: reliable frontal penetration on a T-55 or T-62, but dependent on superior marksmanship to find a weak spot in the face of a T-64 or T-72. However, marksmanship is actually more critical here because the low ROF of a conventional cannon restricts the use of ammo dice.

MBT Viability in Twilight: 2000 4e

Originally posted to the Juhlin.com Twilight: 2000 fan forum.


Once every 1d6 months or so, I’ll raise periscope over on RPG.net to see if anything of interest is being discussed. Back in November, I noticed this thread on running a tank-focused campaign in a post-apoc world. This prompted some thoughts on the viability of such a campaign in Twilight: 2000.

Long-time denizens of the usual fora and mailings lists, or capable search engine operators, will no doubt recall or find several threads on this topic from previous editions. The fan base has generally concluded that running a tank is a loser’s game for PCs due to the logistical issues of fuel, parts, and main gun ammo, as well as the tactical issue of being a huge effing target. However, I don’t think we’ve taken a detailed look at the issue in the light of the game’s fourth edition, so let’s see if the dead horse has a few more resonant thumps left in it.

With a limited selection of tanks available in the 4e core rules, I chose to focus my initial work on the T-72.

Fuel Economy

… so, in terms of fuel economy, the 4e rules give us roughly equivalent fuel economy over distance when running on diesel, but are much more favorable if we retain the conceit of diesel engines being converted to alcohol fuel. Interestingly, 4e’s road movement speed is significantly lower than 2e’s.

Fuel Production

But what about those stills? Well, let’s look at the means of alcohol fuel production in 2e and 4e:

Again, 4e is considerably more generous/forgiving, assuming both a 2e party and a 4e party are using mobile facilities. What becomes a crushing logistical impossibility in 2e is actually kind of feasible in 4e… at least, from a strict numbers perspective.


Edited 02 Jan 2024: Part 2 of this post is now up here.