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Tweaking Power Projection for Small-Ship Campaigns

This article originally appeared in the January/February 2022 issue.

Power Projection Overview

Power Projection by British Isles Traveller Support (BITS) is an adaptation of Ground Zero Games (GZG)’s fast-moving starship combat game Full Thrust to the Traveller universe.

Power Projection: Fleet is the main game, including full-size High Guard/MegaTraveller ships and conversion rules, boarding actions, planetary assault/defense, and Trillion Credit Squadron/Pocket Empires campaign rules.

Power Projection: Escort is a stripped-down version centering around Imperial and Zhodani ships of under 10,000 tons.

The game incorporates a vector movement system based directly on that of GDW’s Mayday, with its past-position and future-position markers. Since then, this has been superseded by a simpler vector-movement system from GZG’s Full Thrust: Fleet Book Volume 1 which uses only a direction indicator (vector direction) under the ship miniature, a written-down movement “speed” (vector size), and the facing of the ship miniature itself (direction of thrust changing the vector).

Ships have “hit points” in the form of “Structure Boxes” determined by tonnage and divided as evenly as possible between four rows. As a ship takes damage, structure boxes are marked off; when an entire row is marked off, a series of “system checks” is rolled to determine which systems (weapons, drives, computers, etc) has been degraded/disabled/destroyed. (This is taken directly from box-stock Full Thrust.)

Hits and damage are determined differently for spinal mount weapons and “secondary weapons” (bays, turrets, everything else).

Spinal mounts roll to hit (with DMs for range modifiers, relative computer size, and agility) then roll damage dice directly—4-7 dice depending on spinal mount size. For spinal particle accelerators, damage dice are subtracted according to the target ship’s armor; spinal meson guns roll an extra penetration roll vs configuration and/or meson screens, then do the full damage dice.

Secondary (non-spinal-mount) weapons roll D6 on a “Secondary Weapon Damage Table”, a matrix which determines the damage done depending on the die roll and table row. Plus DMs (such as nuclear missiles, high-intensity missiles, range modifiers, and relative computer size) shift the roll up one or more table rows for more damage; minus DMs (such as defensive agility, relative computer size, anti-missile fire, sandcaster clouds, or hull armor) shift the roll down one or more rows for less damage.

Rule-of-Thumb: One Power Projection DM equals between three and six High Guard USP factors.

The game is based around ships of the High Guard and MegaTraveller periods; as a consequence, it has to handle a range of ship sizes from 100 to 1 million tons, spanning small-, medium-, and large-ship campaigns. Because it has to handle such disparate sizes, Power Projection gets a little coarse at the low end, the small-ship campaigns of Power Projection: Escort.

Problems and Fixes

Power Projection needs some rule tweaks to fix these problems for small-ship campaigns. The problem is how to rescale for small ships without toughening the big ships too much or adding too much complication.

Small Ships are Too Easily Destroyed

On the Power Projection: Escort scale, Structure Boxes (ship hit points) are allocated at one for every 500 tons of ship. This means anything under 600 tons (such as almost all player-character ships) is a one-hit kill; there is no taking of damage as occurs in stock Traveller.

Solution: Add additional Structure Boxes for the small ships. For the first 1000 tons of ship, allocate one Structure Box for every 100 tons of ship instead of every 500. (In Classic Traveller, 100 tons is the basic size increment for small ships.)

On small ships, this allows a ship to survive more than one hit, at the cost of damage check rolls to determine which ship systems were trashed.

On larger ships, this adds only two boxes to each damage check row; with their number of total and row boxes, this should not toughen them too much.

The additional boxes could be outlined in a different color, to distinguish them from those allocated in box-stock Power Projection.

“Standard Weapon Batteries” Span Too Great a Power Range

Secondary (non-spinal) weapon battery strengths are based on High Guard’s USP weapon factors; USP Factor 1-6 is a “standard battery”; Factor 7-9 is a “High-Power battery” (marked with a “+” sign), with hit/damage starting one row up on the Secondary Weapon table. This means a single-laser turret on a Type S Scout (Factor-1 or 2) and a five-triple-turret battery on a larger ship (Factor-6) are both “standard batteries”.

Solution: Add a “Low-Power Battery” for USP Factors 1-3; Factors 4-6 would remain a “Standard Battery”.

Low-power Batteries start one row down on the Secondary Weapons table, with a base row of “Reduced Damage 1”.

These batteries are marked with a “-”; if playing box-stock rules, treat them as Standard Batteries.

Special Case — Overpowered Missile Bays

At Tech Levels 14 and 15, 100-ton missile bays have a USP Factor of 10 (A), going off the other end of the normal 1-9 scale.

In Power Projection, bay weapons of USP Factor 10+ become “++” batteries, starting another row up on the table, with a base row of “Enhanced Damage 1”.

These super-powered batteries are marked “++”; treat them as normal High-powered (“+”) Batteries if playing box-stock rules.

General Tweaks

These are not problems per se, but general adaptations and simplifications.

Adapting Plantier Shields

Power Projection: Fleet contains rules for the Traveller-standard Black Globe forcefield generators. An earlier/alternative defensive system in early Traveller campaigns were “Plantier Shields”, a simple shield generator that directly traded off Maneuver Drive gees for High Guard armor factors without the complications of Black Globes. Since one Power Projection armor point = 6 High Guard armor factors, Plantier Shields could up a ship’s defenses by at most one additional armor point at a cost in agility; this would be worthwhile for low-agility Book 2 ships (such as Beyond Book 2, the Shavian Empire, and the Foible Federation) but not for high-agility High Guard designs.

There are two possible ways to adapt this to Power Projection:

The Complex/Precise way – calculate the Maneuver gees and agility modifier where the ship armor plus the Plantier Shield boost goes over the Power Projection armor thresholds of 6, 12, 18, or 24.

The Quick-and-Dirty way – If the ship is Maneuver-3 or more, add 1 Power Projection armor point when using half your M-drive thrust or less.

Mark Plantier shield armor points as armor points, but in a different color, with the letter Pi (π) or the threshold G-rating within the armor point circle.

Surface Bombardment with Particle Accelerators

Under both High Guard and Power Projection, particle accelerators cannot be used for surface bombardment on any world with an atmosphere. If atmosphere (and magnetosphere) degrade a particle beam, it is likely to degrade less if the atmosphere is thin. To simulate this, treat atmosphere vs particle beams as follows:

Simplified Meson Defenses

In both High Guard and Power Projection, only meson screens and configuration can defend against meson guns. Power Projection retains the High Guard system of making an additional die roll to penetrate the meson screen after hitting. A simpler way would be to treat the meson screen and configuration as armor, similar to the armor points vs. a particle beam.

For spinal mounts, instead of rolling penetration vs. meson screen separately add the meson screen and configuration levels and treat this as you would armor vs. a particle-beam hit. Spinal mounts subtract one die per screen/config level (starting with the highest-rolled die) and smaller mounts drop rows on the Secondary Weapons table.

For “secondary” meson guns, shift the die results down one row on the Secondary Weapons Table for each configuration and/or meson screen factor.

Simplified Bookkeeping of DMs

Power Projection retains High Guard’s numerous to-hit modifiers, albeit on a different scale. To simplify bookkeeping during play, sum the Offensive and Defensive modifiers into a single value for the ship and each of its weapon types.