Honor Harrington Full Thrust Adaptation, v2

This is version two of Honor Harrington Full Thrust rules. This is an adaptation based on my first version of the rules, feedback from various playtest, and information from the FTGZG-L mailing list.

This is not meant as a challenge to David Weber's Copyright on the Honor Harrington novels. Anybody trying to use this document in such a way should be shot and have horrible things done to his or her body. This is mean to increase enjoyment of Weber's novels, not take away Weber's rightful ownership.

Design Notes

David Weber goes to great lengths to describe velocities and ranges of the weapons in the Honor Harrington universe. His descriptions of his battles are chock full of 'hard' data. Thus, it is possible (once certain assumptions are made) to convert FT 'units' into actual SI distances and times.

The original version of the rules assumed that escorts at full military power, were capable of pulling 580 to 600 g's, had a FT thrust of 8. This meant a single thrust point was 85 g's. If we assumed one turn was four minutes, we had one FT 'unit' equating to 25 000 km. This places one light second at twelve units.

However, this lead to a playability problem. Missiles at their lowest accel settings, have a top range of around 6 million kilometers, or over twenty light seconds, over 240 units! The only way to match that is by increasing the period of time a turn represents, and increasing the distance one unit represents. However, beyond a certain point, this defeats the purpose of the FT system, which simulates ship to ship combat. A ship can usually shoot itself dry in twenty minutes. Most combats in the HH universe are also extremely decisive, being settled within ten minutes. Long turns would cause all this detail to disappear, robbing the variety and richness of the FT system. Thus the HH universe, as envisioned by David Weber, isn't very playable with a tabletop game at the ship to ship level.

Thus, to make the game a little more playable, I've made some changes to the scales things operate on. If weapon ranges are reduced drastically, then all scales can be reduced accordingly. The current scales I've adopted make a turn 30 seconds, a thrust point 60 g's, which means one light second is around 11,000 units. (1 FT unit is 280km, roughly.) Laser/Grasers have a top range of around 3000km - 5000km, and missiles top out at 20 000km. Missiles also don't accelerate as fast. Ship acceleration curves are only slightly modified, though ship maximum speed is seriously reduced. I've also taken advantage of the new construction systems as described in FT:Fleet Book; it makes life a lot easier. To make room for campaign style actions, I've introduced a 'trans-light' drive to allow ships to move, but not fight, at high sublight speeds.

I have also taken some liberties; for example, the equations given in the construction section of the rules aren't even close to reality. The boundary conditions are pretty messed up (the 500 MASS should be a limit that comes out of the equations, not set arbitrarily), and the slope isn't what I want (there should be an asymptotic approach to zero, at the end of the curve, much like an inverted tangent function, or perhaps the solution space to a certain family of DEs), but, given that I'm doing this on a bus somewhere on the 403 between Hamilton and Toronto, without reference books, I hope I can be forgiven.

When all these changes are made, we get something that isn't Honor Harrington, but feels somewhat the same. At least, I get the same ball of fear in my stomach when somebody flushes their missile pods at me. (8-)

However, it is worthy to note that playable doesn't necessarily mean 'fun.' This is the Honor Harrington universe, where ship lethality is amazingly high. Entire task forces can disappear in the face of a well timed, well executed ambush. (Task Forces consisting of a dozen SDNs, plus all required supporting units!) Gamers wanting a lower body count will want to turn elsewhere.

Turn Order

  1. Plot Movement (Secret)

  2. Fire Missile Weapons

  3. Perform Ship Movement

  4. Missile Weapons Movement

  5. Resolving Firing

Base Rules

These rule modifications apply to FT2.5 i.e. Full Thrust with standard Fleet Book Rule modifications.

Arcs are slightly modified. There are only four arcs, forward, aft, port and starboard. The port and starboard arcs are created by combining the forward/aft port and forward/aft starboard arcs.

Changes to Standard Systems

Standard FT Templates are used, with the following systems icons added:

1 Reactor Icon for each Reactor
1 Inertial Compensator Icon


Movement uses the vector rules as described in Fleet Book.

The Rolling Ship rule is used as per Fleet Book.

Ships in the "Honor Harrington" universe move by the use of the impeller wedge, two bands of imprevious gravity stress covering the top and bottom of the ship. Because of the existence of the wedge, it is possible for a ship to 'roll wedge' and interpose the stress band between a ship and an enemy.

A ship rolls wedge against one opposing enemy ship.

There is no effect on fire from ships outside the arc of the enemy ship. For ships that are in the same arc as the selected ship, a die is rolled on a 1 or 2, no effect on fire. On 3-5 the wedge acts as another level of screens. On a 6, all fire is totally negated.

For fire from the selected ship, roll the die. On a 1, the wedge acts as another level of screens. On any other roll, fire is totally negated from the target.

When a ship has rolled wedge, any ships in the same arc and the opposing arc (180) as the selected enemy ship cannot be fired upon by the rolled ship.

The maximum thrust values given for ships represents 80% of their maximum thrust values. This provides the saftey margin required by the inertial compensator, to prevent compenstaor failure (as things slamming backwards at 500gs tends to break things...)

It is possible to override this saftey measure, and run at full military power. For every turn that a ship runs at full military power, roll 3d6. On a 3, the ship's compensator has failed, and a lot of stuff gets turned into jelly. (This rule could be considered optional, but it makes things SO much more interesting.)

Ships will have two thrust ratings, one the standard 80% 'max' power, and the 'full military power' rating.

Military Ships have a top speed of 36 under impeller drive. Beyond this point, particle and radiation shielding begins to breakdown, with deterimental effects for the ship and crew. Civilian ships have a top speed of 18.

If the top speed of 36 was a hard and fast limit, interstellar commerce would be extremely expensive. (Imagine crossing fifty light years in twenty days, and then taking thirty to get from the hyper limit to the destination of the planet.) The invention of Trans-light drive helped solve that problem.

Every ship with an impeller wedge can go trans-light; it is simply a reconfiguration of the gravity wedges. A ship must declare that it is going translight two turns before the drive kicks in. During that turn, it loses its wedge (and its sidewalls.) All other systems function normally, however. The turn after that, a 'cone' of gravity stress forms around the ship. This cone completely isolates the front three arcs, permitting no fire either in or out. The aft arc is wide open, however. The ship itself may not maneuver or perform any other actions. Finally, on the turn itself, a band of gravity stress covers up the stern, and the ship accelerates away at ten times its normal thrust, with top speeds around .8c. (The gravity bands acts as wonderful shielding.)

Trans-light operation is also limited by the gravity gradient, though the range at which it may operate is usually much deeper in then the hyper limit. Planets, however, do usually generate a sufficient gravity gradient to prevent trans-light from functioning, though this depends heavily on the size and composition of the planet involved.

A ship can go FTL, if the ship is outside the hyper limit (as defined by the scenario.) It takes about six minutes (twelve turns) for the hyper generator to recycle after usage. (Which means if a group of ships jumps in, it takes twelve turns before they can jump back out.) A ship exiting hyper space can have a top speed of 4; a ship entering hyper can be travelling no faster then a speed of 4.

A ship entering FTL can have wedges and sidewalls active (baring some special effects with Gravity Waves, which only create problems in scenarios.) The ship declares it is making a jump the turn before the jump occurs. (Turn N-1, declare jump, must stay in a straight line path with speed less than four, Turn N, on the movement phase, the ship jumps clear.)

Damage to a ships hyper generator while preparing to jump is usually fatal, as the energy discharge splatters across the engine room, usually opening up several reactors. Perform an immediate threshold check on ALL reactors in the ship, plus remove one entire row of boxes from the ship.

Ships in the HH universe move and fight on the power of fusion reactors. A ship has one Reactor for every 60 MASS, plus one. (So a MASS 50 ship has two reactors, a MASS 300 ship has 6, etc.) Ships under 30 MASS only have one reactor. If a reactor fails a threshold check, roll a d6. On a 6, the fusion bottle has failed catastrophically, and the bottle vents, destroying the ship. Otherwise, the failsafes work, and the reactor shutsdown.

A Captain can shut down reactors in an attempt to reduce the chance of a bottle failing. Treat as a shutdown reactor, except that it may be restarted at any time.

A ship requires the number of reactors aboard, minus one, as the minimum to fight the ship at full capacity. (i.e. a ship with five reactors would require four to operate at full capacity.) The exception is, of course, when there's only one reactor aboard.

A ships lose reactors, they undergo the effects as detailed in the chart:

R	1    2    3    4    5    6    7   8   9   10
E   0   Z    Z    Z    Z    Z    Z    Z   Z   Z    Z 
A   1	-    -    B    B    C    C    C   C   C    C
C   2        -    -    A    B    B    B   C   C    C
T   3             -    -    A    B    B   B   C    C
O   4                  -    -    A    A   B   B    B
R   5                       -    -    A   A   B    B
S   6                            -    -   A   A    B
    7                                 -   -   A    A
L   8                                     -   -    A
E   9                                         -    -
F  10                                              -
Functions: Thrust, ONE Broadside, Chase Weapons (Fore/Aft), Defences (PDS/ECM)

Offensive Weapons

FT firecons act as global fire controls. A weapon can go into local fire control, but one less die is rolled for the class of weapon (e.g. if a weapon rolled 4d8 to resolve damage, only 3d8 is rolled in local control.) Weapons that roll one die have a -2 applied to their damage code. A ship can engage as many targets as it has weapons.

Unless otherwise stated, all weapons can only fire once per turn.

The primary weapon of the Honor Harrington universe is the missile. Each weapon system requires two purchase; the weapon system, and the magazine to serve that weapon.

Missiles are treated like one-shot fighters. A system launches six dice worth of missiles (a salvo) every turn. (Another way: treat as a squadron of six fighters.)

A target must be in the same arc as covered by the launcher.

Missiles, when lauched, are moved 6" out from the side that they were launched from. Then they move as fighters: 12" movement, over four movement phases, tracking targets within a 120 degree cone in the front of the missile. Or, they can be set to 'speed' mode, traveling 18" over two turns.

Missile damage is scored by reading the damage of each die directly, divided by two, round up. Missiles have an attack range of 2". Missiles are not subject to the re-roll rule. A 1 is always a miss. Note: They do not have to end up within 2" of their targets, just pass within 2".

Missiles are dumb, and must fly a straight line course to their targets. You cannot maneuver missiles around a point defence escort, for example. Likewise, they can be deceived by Banzai Jamming (see below). However, they will ignore all other targets except for their primary target, even if the primary target has already been reduced to slag by a previous weapon i.e. they can't tell if attacking their target is a waste of ammo or not. However, if their primary target is in 2" range, and other targets are in 2", the salvo may attack them. Randomly select among the targets within 2", with the primary target getting two changes (e.g. three targets in 2", roll a d4: 1-2 Primary Target, 3 Target One, 4 Target Two).

Missile Table:
Level Die Mass Pts
1 d4 1 2
2 d6 2 4
3 d8 3 8
4 d10 5 16
5 d12 10 32
Magazines contain 16 'salvoes' of fire. Each magazine can serve all the weapons of that level on the ship, and cost half the mass and points of the respective launcher i.e. a Level 4 magazine would cost 3 MASS and 18 points. Level 1 Magazines contain 24 'salvoes' of fire.

A Captain can 'double tap'; rotate the ship so that one broadside fires on a time delay, then roll the ship so that the second broadside fires at the same time that the first broadside accelerates way. This burns ammo twice as fast, you lose the initial 6" acceleration, and costs MASS div 75 in Thrust points. However, you throw 12 dice squadrons as opposed to six.

A Captain can fire conventional nuclear warheads as opposed to the X-ray warhead weapons that are normally fired. Nuclear warheads require direct hits to be effective, so they have an attack range of 0 i.e. they must touch the center of the model to attack. In addition, because they require direct hits, they are much easier targets for point defence. PDS effects are doubled. However, if they get through, they do double damage.

A Captain can also fire sidewall penetrators. These also require direct hits, and point defence is also twice as effective. However, if these missiles hit (i.e. reach point blank range), all of a ship's screens on the impacted side go down, as if the systems failed a threshold check. No other damage occurs.

Mass: 2 / Cost: 30
These pods are one shot 'disposable' pods that fire one broadside of missiles, as per a level 4 battery. These pods can be towed to an area of battle, or carried as cargo and dumped overboard. A ship can 'tow' its MASS divided by 30 of these pods with no degredation of its acceleration rates. (Round down). Every additional pod reduces a ships acceleration by 1 point.

If any missile fire is directed at a ship towing pods, or at an area of space with pods, and these missiles reach attack range, then all the pods in the radius of the attack range are rendered useless (even if they're being towed behind a different ship.) This reflects the vulnerability to 'soft kills' from the EMP generated by missile detenations. Missile Pods don't have the room for the electromagnetic accelerators that ship launchers have; there's no 6" push either.

ENERGY WEAPONS Close-in weaponry is represented by lasers and grasers. Lasers are lighter then grasers, but grasers have more 'smashing' power.

Damage for these energy weapons is read right off the dice. Range attenuation occurs, according to the chart below. If a die has a damage roll of six or more, roll the dice again, applying half the damage to the armour, and half to internal structure. This can only happen once.

Range Chart:
Weapon 1 2 3 4 5 6 7 8 9 10 11+
Laser 0 -1 -1 -2 -3 -5 Out of Range
Graser 0 0 0 -1 -1 -1 -3 -3 -5 -7 Out of Range
Laser Table:
Level Dice Mass Pts
1 1d6 1 3
2 2d6 2 6
3 3d6 3 12
4 4d6 4 24

Graser Table:
Level Dice Mass Pts
1 1d8 2 6
2 2d8 4 9
3 3d8 6 18
4 4d8 8 36
Mass: 2 / Cost: 12 / Range: 6 / Damage: 4d8
Energy torpedoes hit using the basic battery to-hit roll as defined for standard beam batteries. For every hit, roll 4d8 dice for damage. Point defence weapons are useless again Energy Torps. However, if a ship mounts any sort of screens, these weapons are useless (they can't penetrate sidewalls.) (This means, however, that these weapons can shoot 'up the kilt/down the throat'.)

Mass: 5 / Cost: 24 / Range: 3 / Damage: Special
A ship hit by the grav lance loses all its screens, on the side of the ship hit by the grav lance, as if all the screens failed a threshold check. Roll the basic FT battery to-hit roll; any hit has the above affect.


Point Defence Systems come in various types, which differ in the size of dice they roll, and their effective range. All PDS systems can fire on any missiles in their attack range, even if the missiles are intended for a different target. Each PDS system can only fire once a turn.

PDS systems get a last ditch shot at incoming missiles, if the PDS system hasn't fired that turn at another group of missiles.

Total kills are modified by half DIFFERENTIAL; and a high number is always a miss. PDS Table:
Class Dice Mass Points Range
1 1d4 2 4 4"
2 1d6 3 6 6"
3 2d6 5 10 8"
4 2d6 6 12 10"
5 1d6 4 8 10"
6 2d8 8 16 10"
Honor Harrington Universe starships are equiped with gravity sidewalls, closing off the port/starboard aspects of their wedges. However, due to the nature of propulsion in the Universe, the fore/aft aspects cannot be protected by these systems; thus any shots "down the throat" or "up the kilt" will not be attenuated and can cause massive damage.

Each installation has a port/starboard icon. When threshold checks occur, check against both systems. It is possible to lose one side without the other, or both.

Each level of screen will stop one die roll of damage against all damage dice rolled against it, per 'strike', per turn. This roll is halved against misisle attacks.

Level Mass(whichever is greater) Points Roll
1 3 or 5% MASS 20 1d4
2 6 or 10% MASS 40 2d4
3 12 or 15% MASS 80 2d6
4 24 or 20% MASS 120 2d8

ECM and Sensors

All ships in the HH universe carry extremely comprehensive electronics countermeasures suite, designed to combat enemy sensors and enemy fire control.

In previous versions of these rules, there was an extremely comprehensive sensors/ECM ruleset, involving contested rolls, masking, cloaking, purchasable systems etc. In addition, in the Weber books, sensors and their use form a very important and integral part of the battle. However these rules tripled the length of time a turn took, as well as added to the general confusion.

Thus, to aid playability, everyting has been distilled into two ratings, fire control and ECM. Each ship has these two ratings. In addition, several of the sensor options previous presented are still available, but in an extremely simplified format.

While these rules do add complication to the game, it is highly recommended that they be used. Many of the battles in the HH universe hinge on the control of information; the use of it, and the denying of it to the enemy.

Most ships have an ECM rating; this represents the quantity and quality of the ECM systems and operators aboard a vessel. A ship that shuts down its ECM suite has an effective rating of 0.

Most ships have a Fire Control rating; this represents the quantity and quality of a ships' offensive sensors and the crew manning them. A ship that shuts down its FC has an effective rating of 0.

Aspects of these rules will ask for the Sensor DIFFERENTIAL rating. This is the attackers Fire Control - the defenders ECM. Keep all signs.

A ship can be in one of three modes; active, passive, silent running.

An active ship has its sensors energized and sending energy out to find targets and determine information about them. The base range for active sensors is 12", plus the DIFFERENTIAL rating. Active sensors will determine every target in this range, plus a mass range. (Mod 20 i.e. 0-20, 21-40, etc. minus the DIFFERENTIAL rating. For example, attacker FC is 4, defenders ECM is 0, Mass is determined mod 16, sensor range 28") Velocity information is given, and if a ship's class is known to your side, it will give class information. Active sensors will find ships running silent.

A variant of active sensors is the hull map; if a target comes within 6", a hull map can be created. This gives information as to the external systems of the ship (including, but not limited to, complete weapons info.)

Passive sensors radiate no energy. They are good to a range of 40", except versus ships who are active, when they are good to a range of 64". Passive sensors will give you wedge readings, which will give you the class of a ship, if you've encountered that ship class before. If not, it will give MASS Readings mod 40, minus the DIFFERENTIAL rating. Passive Sensors Range is affected by DOUBLE the DIFFERENTIAL Rating.

Beyond the base range above, if a ship uses main thrust, it appears on the map, with no other information, other than a MASS Range mod 60. (Minus the DIFFERENTIAL.) If the ship doesn't use main thrust, it is effectively silent running (even though it may radiate energy normally.)

A ship in silent running is invisible to passive sensors (but not active ones.) A ship in silent running cannot use main thrust, fire, or emit any emissions (this includes ECM and fire control, or communications.) In particular, since the ship's engines are shutdown, the ship has no wedge, or no sidewalls to interdict enemy fire. However, the ship can rotate and push using thrusters, with a maximum push of '2'.

It takes one turn for a ship to enter silent running, and one turn for a ship to come out of silent running. Note this in the orders plot for the turn before. (I.e. Ship out of silent running in turn 6 means the ship will be fully functional in turn 7.)

The location of missile pods can only be determined by active sensors.

A ship can set itself up as a big missile target, using its ECM to attract missiles away from more vulnerable targets. The number of missiles decoyed is the ratio of the defenders ECM to the attackers Fire Control rating. For example, if the ECM Rating is 4 and the FC rating is 4, all the missiles would go after the radiating target.

A ship employing banzai jamming lights up the entire universe; everybody knows what that ship is doing.

A ship can attempt to 'disguise' itself by the use of its ECM systems. A ship can make itself appear larger or smaller, or disguise its emissions so that it resembles a different class of that type of ship.

This can only work while a ship is being viewed with passive sensors. A ship can increase its MASS rating by its ECM rating x 50, or decrease it by its ECM Rating x 20. An enemy ship can attempt to defeat the masking by rolling own FIRE CONTROL rating or under, minus half the enemy ECM rating (round down).


Systems damage works the same way as in FT:FB, with the following changes: 1) ECM and Fire Control ratings are reduced by a quarter for every damage track lost. Round up until the last track, then round down.

2) Engines are affected as per EFSB - the thrust of a ship is divided into elements of two (with an extra one left over, if required). Roll a threshold check against all engines, taking out the ones damaged. Likewise, repairs are performed in the same way.

3) All systems (point defence, energy weapons, missile weapons, etc) represents collections of systems, as opposed to discrete items. The first failed threshold damages the system, so it operates at half capacity. The second threshold hit destroys the system. (See Missile exception below.)

4) The first failed threshold check on a missile battery creates a -1 to damage, and a halving of the dice launched. The second failed threshold check destroys the system.

5) A hit on the Inertial Compensator only succeeds on a 6, regardless of what damage track you're on. If the Compensator is hit, roll 3d6; on a 3, 4 or 5, the failsafe has failed to engage, and the ship's crew is now paste. On any other roll, the failsafe has engaged, and the ship may no longer push or accelerate until the compensator is repaired. It may rotate, however.


A ship that surrenders can "strike the wedge." This is a complete engine shutdown. Ship that has 'struck' has no wedge, and no sidewalls.


Ship construction follows FT:FB rules, with the following changes. NOTE: The largest ship you can ever build is a MASS 500 ship. I'm hoping to rework these equations so that they don't present an arbitrary limit. Stay tuned. Maximum Thrust Equation
Due to the physics of the Impeller drive and the Inertial Compensator, there exists a MASS at which the ship can no longer accelerate. The curve is defined roughly as:

(MAX THRUST) y = ( (500-x)^0.755 ) / 10.90

Where x is the MASS of the ship, and y represents top thrust at 80% power. Note that this determines how fast the ship can go, not how fast it will go. That depends on the thrust points purchased for the ship.

This also means that no ship can weigh more than 500 MASS.

Points per Thrust Point Equation
The number of points required for a given thrust rating is determined by:

y = thrust desired*5 ^ (1 + MASS/500)

Where thrust desired is the 100% throttle setting, and MASS is the MASS of the ship.

MASS per Thrust Point Equation
The MASS of a ship's impellars is given by: MASS = THRUST * (MASS ^ 2) / (50 * MASS)

Thrust desired is the 100% throttle setting.

Weapon Limitations by ARC
As ships get larger, their beams become much shorter in respect to their lengths. Thus, small ships can mount as much as 20-25% of the armament as chase armament, while large ships can only mount 4 or 5%. This equation deals with that: y = (500 - MASS) / 20 y is the percentage of weapons that may be mounted fore and aft. (Both fore and aft weapons count in the percentage given above. ) Hull Selection is as Fleet Book. However, if you pick a certain strength hull, you get the hull above it in terms of hull boxes e.g. a WEAK hull would MASS 10%, and provide 20% Hull Boxes.