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Flexible Battery Rules

This article originally appeared on the pre-magazine Freelance Traveller website in 2002, and was reprinted in the August 2015 issue.


One odd aspect of ship combat as detailed in Book 5: High Guard is the concept of battery configurations, specifically those batteries consisting of turrets. While the idea that a single bay weapon or spinal mount is considered a single battery is intuitive, the idea that turrets must be collected into permanent battery assignments is not.

This variant introduces the idea of “flexible” turret battery assignments to Book 5: High Guard design and combat. An argument for the historical nature of flexible batteries will be made. The use and desirability of flexible batteries in combat will be discussed. The costs and requirements for either building a vessel with or retrofitting an existing vessel with flexible batteries will be covered also.

Hopefully, both GMs and PCs alike will enjoy introducing flexible batteries to their campaigns.

Why flexible batteries?

Historically, fire control for weapons batteries onboard ships has been a challenge ever since the first cannon were installed. Hollywood aside, the great “line of battle” ships from the Age of Sail did not fire their huge broadsides of dozens of cannon all at once. Such a practice would have shaken their ships apart. Instead, broadsides were fired in a ripple pattern, each gun captain firing his piece in turn, from bow to stern, as the target came on bearing. Fire control existed in the person of the gun captain himself, he and his crew muscled their bulky charge with handspikes, raising the breech a bit or shifting the gun slightly to one side or another. With combat taking place at the range of a pistol shot, nothing better was really needed.

Then, the Industrial Age changed that.

Towards to turn of the last century, it was apparent to even the most hide-bound of naval officers that fire control had not kept up with the guns themselves. The British off Alexandria and the Americans off Santiago were chagrined to learn just how few of the huge shells their new and mighty guns threw actually hit their targets. In the case of the Americans, only one or two 10-inch shells out of hundreds fired managed to hit any Spanish vessel.

The solution was both simple and controversial; centrally directed gunnery fire. Simple in that it worked, controversial in the fact that it removed control of the guns from the men serving them. Detractors bemoaned this loss of control, but the much-improved accuracy eventually won everyone over.

By the time dreadnoughts prowled the world’s oceans, director fire control was the standard. But, individually controlled fire was never completely abandoned. It was kept around as a back up in case a ship’s central control system was lost or damaged.

Even under central fire direction, a warship’s batteries were not permanently grouped. A vessel could split the fire of its main turrets to engage more than one target simultaneously. Smaller guns could either tackle single aircraft alone or combine to claw a kamikaze out of the sky. Despite central fire control, crews could still mix and match their vessel’s weaponry to precisely meet their needs in combat.

In Book 2: Starships, Traveller introduced local fire control as part of its space combat system. A gunner had complete control over the weapons installed in the turret she manned. Given the role-playing emphasis of Traveller, this was a natural and correct decision.

Later, in Book 5: High Guard, centralized fire control was introduced. Turrets armed with similar weapons could now be grouped into batteries to increase the chances of hitting an opponent, overcoming his defenses, and causing him damage. These battery groups were “set in stone”, however. Turrets were permanently assigned to a given battery at the time a vessel was designed and not by the crew in response to “on the spot” combat requirements.

If TL 5 and 6 warships without fancy electronics could flex their battery groupings as the combat situation dictated, why couldn’t the near-magical vessels of the 57th century?

Flexible Batteries – Combat Rules

Battery Composition: Simply put, during each offensive and defensive fire turn of a space combat round, a crew can join turrets armed with the same weapons into whatever battery sizes they see fit.

As previously stated in Book 5: High Guard, batteries must be comprised of similar weapons, i.e., beam lasers can only be grouped with beam lasers, missiles with missiles, and so forth.

If a vessel is armed with mixed turrets; meaning turrets holding dissimilar weapons, specific weapons in each turret can be grouped into a battery in the same manner as stated in Book 5: High Guard, i.e., pulse lasers with pulse lasers, sandcasters with sandcaster, and so forth.

Battery Ratings: The total number of weapons grouped into a battery will determine the specific USP code rating for that battery during that round. Check the number of weapons against the Turret Weapons table in Book 5: High Guard to determine the proper USP code. The requirements and bonuses listed in that table remain the same. The upper limit of 9 as an USP code remains the same also.

Example: Three missile launchers grouped into a battery will result in an USP code of 2. If TL13 or above, they will be rated at 3. Five TL13+ launchers will still only be rated as 3, as six launchers are needed to reach the next level on the table. No matter how many missile launchers are grouped together and despite any TL bonus, the flexed missile battery can have an USP code rating of no greater than 9.

Battery Selection: The decisions about a vessel’s specific battery groups for a combat round should be declared prior to the offensive or defensive firing step. Players must announce the specific battery groups they use in each round prior to actually using them. In the case of Book 5: High Guard, the “Pre-combat Decision Step” is a good time to do this.

Example: An 800-dTon mercenary cruiser is armed with eight turrets. Four turrets have triple beam lasers and four turrets have triple missile launchers. The cruiser could fire each laser turret as a battery, resulting in 4 batteries with an USP code of 3 each. The cruiser could fire all four laser turrets as a single battery, resulting in one battery with an USP code of 4. The cruiser could also group two turrets in one battery and fire the remaining turrets as two batteries. This would give the cruiser a single laser battery with an USP code of 4 and two laser batteries with an USP code of 3 apiece.

If a player fails to announce specific battery groupings, a vessel’s default battery groupings are used instead. Please see the section below detailing default groupings.

Manning requirements: Each battery grouping must have a gunner assigned to it. The gunner can either be present in a turret acting as part of that battery, a turret holding a weapon acting as part of that battery, or a dedicated fire control station on the vessel. A turret gunner can only fire a battery or the mixed weapons in her turret in the same fire turn. To be eligible to fire a battery, a turret gunner must have at least one weapon assigned to that battery present in her turret. Gunners at fire control stations can only fire batteries; however a battery can be made up of a single weapon.

Example: A 200-dTon free trader is armed with 2 turrets. Both turrets are mixed and contain a single laser, a single missile, and a single sandcaster. There is a gunner in each turret and a gunner at a fire control station on the bridge. The gunner at the fire control station could fire both lasers in a single battery, leaving the turret gunners to fire their remaining missiles and sandcasters. If a turret gunner fired the combined laser battery, he could not then fire the missile and sandcaster remaining in his turret. The fire control gunner could fire either of those weapons from her station as a one-weapon battery, but not both.

Default Battery Configuration: When a vessel is first laid down with flexible batteries, or a vessel is retrofitted with flexible batteries, a default battery configuration is created. All turret weapons are grouped into batteries as described in Book 5: High Guard. If a player fails to announce specific battery groupings before combat takes place or if a vessel's computer is destroyed or off-line, the default battery configuration is used.

Damage Results: When a damage roll results in a turret or weapons hit, the current battery configuration is used to determine the proper damage. Destroy either the necessary number of turrets or weapons to meet the damage requirements.

Example 1: An 800-dTon mercenary cruiser is built with the flexible battery option. During a combat round, all 4 triple beam laser turrets are grouped into a single battery with an USP code of 5. The cruiser receives a weapons-1 hit during the current combat and her opponent chooses to inflict the damage on the single laser. Book 5: High Guard states that if only one battery of the type selected exists, then reduce the USP code by the indicated amount. The cruiser had grouped 12 beam lasers into the battery for an USP code of 5. An USP code of 4 requires at least 6 but no more then 9 beam lasers. Of the 12 beam lasers involved, 3 must be destroyed to meet the damage requirements, so one triple laser turret is destroyed.

Example 2: Another 800-dTon mercenary cruiser has currently grouped her four beam laser turrets into two USP code 4 batteries. She receives a weapons-1 damage result also. Because there are two laser batteries, one must be destroyed. In this case, two triple laser turrets are removed. If the cruiser had been using her lasers in four batteries, only one battery, i.e., one turret, would have been lost.

Flexible Batteries – Design and Role Playing Rules

Cost: Vessels can either be built with flexible batteries or retrofitted with flexible batteries. If built, all weapon prices should be increased by 10% to reflect added equipment costs. If retrofitted, no new weapons need to be purchased, but 20% of the weapons cost should be charged. Some vessels may retrofit only certain weapon types at one time, i.e., flexing their lasers but not their sandcasters. The price for such a retrofit should be figured for the affected weapons only.

Retrofits can be performed at any starport the referee deems fit to do the work, usually class A or B. Systems with high law levels, A+, may refuse to do the work at all.

The amount of time required for the retrofit can be assumed to be under two weeks and can be performed during a ship’s annual maintenance period.

(Please note: all this refers to civilian or corporate vessels only. Military, scout, and paramilitary vessels can be assumed to already have flexible batteries at no additional costs.)

Software: The software for normal batteries and flexible batteries is not interchangeable. If a vessel has had its batteries retrofitted for flexible operation, then all software must be replaced before a flexible battery can use that option. In the case of Target or Launch, those programs must be replaced before lasers or missiles/sandcasters can be used. Any offensive or defensive program that is involved in firing or aiming weapons can be replaced.

The prices for flexible battery software are the same as for normal software.

Example: A vessel has been retrofitted with flexible batteries for all its weapons. Before the flex option for lasers could be used, the PCs must replace their Target program. New Launch and Target programs would be needed before their missiles could be flexed and a new Gunner Interact program installed before that feature could be used.

Do It Yourself: Referees will undoubtedly find their PCs trying to retrofit their vessels for as cheaply as possible. PCs can attempt to do the work themselves, thus saving on labor costs.

The skills required are gunnery, mechanical, and electronics. A minimum of one level in each skill is necessary. The work can be done in one week for each turret involved with a throw of 9+. Each skill level above one in any of the required skills can be used to affect the success roll.

Additional skill levels can also be spent to reduce the work period by one day at a throw of 8+. At most three characters can be used to perform the work at any one time, any more can not fit in the spaces where the work is done. Additional workers can be used on other shifts if desired, but each shift must have at least the minimum levels in the three required skills.

It is recommended that the referee roll secretly for a “fatal flaw” in the retrofit work. Such a failure, if it occurs, should show up at interesting moments.

The parts the retrofit requires will cost 10% of the purchase price of each weapon involved. These parts cannot normally be manufactured by the PCs, anymore than a missile launcher or beam laser can be manufactured by them.

These parts can be stripped out of another vessel with flexed batteries at the referee’s discretion. One vessel may not have all the parts another requires. Parts may also be damaged during removal. It is strongly recommended that the parts for one style of weapon not be used for another. Parts should not be interchangeable between manufacturers either.

Example: The crew of the Zephyr is attempting to retrofit their vessel. The three PCs involved in the work have gunnery-3, mechanical-2, and electronic-1. They have at least the minimal skill levels in every required skill, so the work can commence. They also have 3 levels beyond the minimal requirements, 2 gunnery and 1 mechanical. They could use those levels to either affect their success roll, or try to shorten the work period, or both.

Writing Software: PCs may attempt to write their own flexible battery software. The same skill and time requirements listed in Book 2: Starships apply. The same success and fatal flaw rolls apply also.


Flexible battery rules should present referees and PCs with yet another to personalize their ships. Using flexible batteries to “outfox” or “outguess” the other side during battle should make space combat much more interesting. Finally, the software and hardware requirements of a flexible battery retrofit could provide any campaign with a long-term goal.

I know flexible batteries added to the fun of our sessions during my GM days. I hope they will do the same to yours.