My #TravellerRPG #Wargame – Using @IndependenceGa6 The Clement Sector setting in High Guard

Ever heard of Eurisko? If you played the (now Classic) Traveller RPG back in the early 1980’s, and especially if you played with capital ships or fleets in Book 5: High Guard or Adventure 5: Trillion Credit Squadron, then you probably heard of it. Eurisko is a representational language written in the Lisp Programming Language that learns through heuristics. Think of it as an early form of AI. Eurisko was used to design the 1981 winner of the Traveller Trillion Credit Squadron National Tournament at the Origins Game Fair that year. In 1982 Eurisko won again. Threatened with the end of the tournament if he entered again, Dr. Lenet withdrew Eurisko from further competition.

I bring up this history because the Eurisko incident often colors many peoples perceptions of High Guard. Since High Guard could be ‘gamed’ by a computer, many decry it as ‘broken’ and not a worthy version of a fleet battle game for the Traveller universe. I disagree. I enjoy High Guard and the companion Adventure 5: Trillion Credit Squadron. Sure, it’s a highly abstracted view of space combat in the Traveller universe, but that very abstraction is what makes it attractive.

The Traveller Itch

Having not picked up a Traveller book in a while, I recently had an itch to dive back into the rules. One awesome aspect of the Traveller series that I really enjoy is all the mini-games possible. From Character Generation (yes, I’ve died in CharGen), to world-building, to building ships, the rules of Traveller, and now the modern successor Cepheus Engine, allow you to create a wide diversity of elements in a system that ensures it all works together.

The Clement Sector: Core Setting Book from Independence Games

One setting for Traveller I really enjoy is The Clement Sector from Independence Games. The Clement Sector is a ‘small ship universe’ where the limits of the “Zimm Drive” keep ships, at least those that are jump capable, under 5,000 Tons. With the Wendy’s Guide series of sourcebooks that detail out entire fleets, I wondered if The Clement Sector and High Guard could mix. So I experimented.

Anderson & Felix, Meet High Guard

Ships in The Clement Sector are constructed using the Anderson & Felix Guide to Naval Architecture. If you are a Traveller RPG historian, you will know that A&F is basically the modern day version of Book 2: Starships updated for Cepheus Engine. This means that A&F is not closely coupled to High Guard like the original Book 2: Starships or Adventure 5: Trillion Credit Squadron were. For my experiment this meant that in some places a little “interpretation” is needed to convert ships from the A&F stats to High Guard which uses the original Universal Ship Profile (USP). The USP was a series of numbers that takes much the details of a ship design and renders it into a single line alpha-numeric characters.

Powerplants, Energy Points, and Agility

In the original High Guard, ships were built with Powerplants that in turn produced Energy Points. As Book 5 stated, “Energy points are used for four purposes: powering weapons, shields, for maneuver drives (for agility), and for computers.” The key factor for High Guard was that ‘Agility’ rating derived by taking energy points not used for computers or weapons or shields and plugging them into the formula A=E/0.01M (where E= Unused Energy Points and M= Mass of the Ship).

Agility is one of the most abstracted elements of the High Guard design in a design that is full of abstractions. Book 5 defines it as follows:

Agility is the ability of a ship to make violent maneuvers and take evasive action while engaging hostile targets. A ship’s agility rating may never exceed its maneuver drive rating.

Book 5: High Guard (2nd Edition 1980), p. 28

It’s clear that Agility is distinctly different that a ship’s maneuver rating. Seeing how it is based on “excess power” it (at least to me) symbolizes how much more you can throw your ship around beyond the usual M-Drive abilities.

Which is the heart of the problem. You see, in A&F the energy requirements in a ship design are actually more simplified than in High Guard. The concept of Energy Points is simply not used in A&F. Unlike High Guard, in A&F computers and turret weapons (presumably this includes barbettes too) are “Unlimited by Power” per the Capital Ship Armament Table on A&F p. 29. This same table specifies how many Bay Weapons per 1000 tons can be carried (based on the Power Plant Rating) as well as if a Spinal Weapon or how many Screens are allowed.

Without a direct translation between High Guard Energy Points and the Armament Power Table in A&F it is impossible to derive an Agility rating. So I asked myself, “How is Agility used in combat, and what would the difference be if it was not used?”

When resolving combat in High Guard, one nice part of the design is that there are actually very few modifiers to worry about (or remember). When making the initial To Hit roll, there really are only three modifiers:

  • + relative computer size
  • – target agility rating
  • + target size modifier

I was worried that, with this few modifiers to start with, simply removing the “- target agility rating” risked skewing the result. Wanting to preserve the intent of the design, I fell back on a lazy solution; change the modifier to “Minus Firers M-Drive Rating/Target M-Drive Rating (rounded down) IF RESULT IS POSITIVE – any NEGATIVE result becomes Target Agility= 0”.

For instance, say a Rattlesnake Attack Craft with M-Drive=5 from Ships of The Clement Sector 7 has jumped a Rucker-class Merchant from Ships of the Clement Sector 16 converted into the System Security/Escort Armament variant with M-Drive=2. When the Rattlesnake attacks the relative drive rating (5:2) computes to a factor of 2, giving the Rattlesnake a -2 DM on its To Hit rolls (better relative “agility”). On the other hand, when the Rucker shoots at the Rattlesnake the relative rating is 2:5 giving a result of -2 which becomes 0 DM modifier.


The second area that needed interpretation was armor. In Cepheus Engine ship combat, the armor rating directly reduces the number of hits. So when a ship is attacked with a salvo of three Basic Missiles (Damage = 1d6 each) launched by a Triple Turret, if the target ship has Armor = 8 then the first eight hits are offset. When designing a ship using A&F, the default armor for higher Tech Levels is Crystaliron which can be added to ships in increments of 5% of the ships tonnage. The maximum armor factor is the Tech Level of the design or 12, whichever is less.

In High Guard, the type of armor is unspecified. Given the rather large armor factors in A&F designs, I wondered it I was over-armoring the designs. A close look at the High Guard Hull Armor formula gave me my solution. The Hull Armor formula tells the designer the percentage of the ship required for that armor factor. At TL 11 (standard in The Clement Sector) the formula is 3+3a where a is the desired armor factor. Using a little backwards math I quickly discovered that the Armor Factor given in a A&F design was using too much space, but if I used the number of “layers”– those 5% elements- the number worked. So a Moltke-class cruiser (Ships of the Clement Sector 3) which is listed as “Crystaliron x2 / 8 points” when converted to High Guard has Armor=2. Unlike Cepheus Engine where armor directly reduces the number of hits, in High Guard armor is a +DM when rolling on the Ship Damage tables. Using this backwards derived formula, armor in The Clement Sector ranges from +1 to +4; a much more reasonable range of modifiers than the +4 to +16(!) using the A&F factors.


Torpedoes are described in A&F as, “…true ship killers…heavy 2.5dT anti-ship missiles….” In A&F missiles inflict damage from 1d6 (Basic Missile) to 3d6 + Crew Hit (Nuclear Missiles). Comparatively, a Basic Torpedo will inflict 4d6 hits, a Nuclear Torpedo causes 6d6 hits, and the heaviest Bomb Pumped Torpedo scores 7d6 damage.

Assuming the High Guard missiles are nuclear, I was able to come up with approximated damage for each USP factor. I then reworked the table using the higher damage potential of the Torpedo. In the end it worked out that I could use the existing High Guard Turret Weapons table and, using the missile column, simply add +1 USP factor to get the Torpedo USP.

Rail Guns

Rail Guns were another weapon found in A&F but not in High Guard. Using the same approach as I did for Torpedoes, I basically figured out that the 50-ton Rail Gun Bay had nearly the same hitting power of a 50-ton Missile Bay, so I used the same USP factor. The primary difference is in combat; the Short range of the Rail Gun earned it a restriction of being unable to fire when at Long Range in High Guard. At Short Range, the Rail Gun earned a +2 DM To Hit but used the Attacking Meson Gun vs Configuration table. This generally means that, absent those other To Hit modifiers, a Rail Gun battery needs to roll an 8+ on 2d6 to hit a Needle/Wedge configuration, or a 6+ to hit a Standard configuration, or an 11+ to hit a Dispersed configuration ship. Sort makes sense, right?

Missile Stocks

In High Guard the number of missiles one had aboard a ship was not a consideration. I always found this interesting given that combat in High Guard usually depicted larger, longer fleet engagements. The ship descriptions in the Ships of the Clement Sector includes the number of missiles on hand. Usually it is a mix of Basic, Nuclear, and Smart Missiles. As any logistics planner will tell you, you can’t face the enemy with an empty quiver of bows! I toyed around with the idea of breaking the load out into the number of turns each missile type could be fired (assuming one round of firing in a turn) but ultimately decided that breaking it out by missile is just too granular for the High Guard system of abstractions. Instead I took the number of missiles available and divided it by how many can be fired in one ‘volley’. This is the number of ‘volleys’ the ship gets before the stores are depleted. Probably only useful in a campaign game or as a special rule like an SDB on patrol too long facing a pirate with a near-depleted stores of missile– make every shot count!

Into Battle?

So, now that I’ve done my homework, will I actually play a game of High Guard in The Clement Sector? Maybe. Like I said before, The Clement Sector is a ‘small ship universe’ meaning space battles are usually smaller affairs with few ships. High Guard is better at resolving larger fleet battles with larger combatants. In the The Hub Federation Ground Forces sourcebook, Appendix 1, some details of the “Battle of Beol” are provided. There may be enough there to make a fleet battle scenario.

Now that I think of it, the Battle of Beol also includes a ground campaign. Maybe I need to look at a Striker (GDW, 1980) campaign next?


Feature image courtesy

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