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Stutterwarp in Traveller

Stutterwarp was discovered by a race outside of main Imperium, in a system that had no exploitable lanthanides. Despite their relatively high technology in other areas, they were unable to develop standard jump drives.

Scientific investigations into FTL travel continued in a different direction than normal. At TL12 They came upon another effect (based on quantum tunneling) enabling fixed length nanojumps to be made at v high speed. (Each nanojump carries the vessel 1/35197 AU (~4250km), and takes 5.1 femtoseconds (5.1*10^-15 s). The maximum cycle rate of these drives is limited and is the important aspect in determining the effective speed made.) At maximum theoretical efficiency TL12 stutterwarp drives can average 11,730,000 cycles a second, covering a distance of 1AU in 0.003 seconds! (~47 times the speed of light)

In use it takes around half an hour to generate a stutterwarp field. During this time the vessel is fairly vulnerable, as the field boundary disrupts/scatters energy & matter traveling through it. This effect is not sufficient to protect the vessel from incoming attacks due to the closeness of the field boundary, but makes all outward weapons fire, active sensors, outward communications or EVA impossible. Once the field has fully developed the craft can make as many nanojumps as it wishes (at least till fuel runs out) at the end of which another half hour is needed for the field to dissipate again. Normal maneuver drives can be used whilst the field is in place but due to the scattering efficiency is reduced (reduce maneuver Gs by 1 min 0.5, and halve agility). Given sufficient computing power, incoming communications and passive sensors can be employed with the field active, the computer deconvolutes the interference from the field boundary. This is just as well because Excellent Passive sensors are required for safe travel, to avoid collisions. Even with the best sensors accidents occasionally happen; a particularly famous case was that of top stutterwarp racer Dimeerky Reno who died on the way back from winning the Ketsre Challenge for the fourteenth time. Apparently his ship materialised around a small cloud of micrometeors with disastrous result.

If the space a stutterwarp materialises in is already occupied the matter remains there and merges with the contents of the stutterwarp field, being carried along on the next nanojump. As most of space is fairly empty this is not normally a problem, as the life support systems are capable of removing the gradual build up of interplanetary material. If a jump takes a vessel into an atmosphere it causes complications! The external atmosphere is added to that inside the ship (including inside every vaccsuit, air bottle etc), raising the internal pressures appropriately and potentially fatally contaminating all internal atmospheres as well.

Each nanojump generates energy, which must be dissipated (as wide band electromagnetic radiation) Many factors affect the drive efficiency and energy loss, these include local gravity, drive condition, weapons hits, maneuver drive use...(using a black globe whilst in stutterwarp would vaporise a ship completely in a few seconds)

Stutterwarps are very temperamental drives, needing constant highly skilled tweaking to keep them at their best; without this maintenance and tuning, cycle times drop rapidly to 1/hr and below, at which point conventional drives are generally faster! Considerable skill is also required to control the exact direction the micro jump will take; this is mainly affected by local gravity and drive node balancing.

The exact technical parameters of the drive system are closely guarded secret, but careless operations have shown that all material within one or more linked spherical fields is affected when the drive is engaged, and that these fields, have a turbulent outer edge extending somewhat beyond the ships hull.

Given the skill required to get the most from the drive, in-system stutterwarp racing is becoming very popular. Due to the speed of light, watching a race does produce strange visual effects, each vessel will suddenly appear (at the point of closest approach) then disappear in both directions simultaneously! The energy dissipation needs make a ship in stutterwarp easily visible, but by the time the light has reached the observer the ship has of course generally moved on

Several military tacticians have also become very excited by the possibilities suggested by the stutterwarp. Fortunately for the rest of known space, there have proved to be difficulties in following up on these possibilities. Since discovering the plans the inventors have refused to fit stutterwarps to any armed vessels (claiming national security may be at stake); indeed, they are very reluctant to install them in any vessel they have not built themselves. Most of the experiments carried out have been on vessels retrofitted with weapons after the stutterwarp was installed.

Use of the stutterwarp for evasive maneuvers has on several occasions proved to be a success, but most experts feel the generation delay, unreliability and expense of the drive rule out its use in warships.

It's not known whether stutterwarp drives can be fitted to starships with standard jump capacity. It is known that the two drive fields produce dangerously unpredictable effects should they overlap. (Theory suggests that this allows some of Jumpspace into our normal dimensions with all the associated chaos.) Operation of a stutterwarp on a vessel with a discharged jump drive has only been tried once as a retrofit on the experimental X-boat Speeda 5, which disappeared without trace on its maiden flight. The project leader, Jan Teller, was lost with the ship, and when his computer records were investigated subsequently, a rough calculation was found supposedly showing the risk of 'self energising of the jump drive' to be negligible. No notes were included to explain the derivation of the equation used, but many sources speculate that the value of 6.62608 quoted was in fact likely to have been Planck's Constant, with an uncharacteristic error missing out the exponent of 10^-34.

Game mechanics


In Combat any sensor or drive hit will also effect the stutterwarp on a roll of 4+ . Unless a direct hit is stored on the drive a normal service will fix this damage. A direct hit requires at least an overhaul to repair, and may require a complete drive replacement.

Design parameters

Volume: 3% of ship's total displacement (minimum 2 disp. tons)
Cost: MCr12 per disp. ton
Fuel: 2x drive volume to create field, plus 1x drive volume for every 24 hrs. of travel.

Each node creates 45m dia. field. Adjacent nodes with touching fields merge to produce cylindrical field.

Changes with TL

TL 16 development could enable displacement/removal of material in area about to be occupied. Getting rid of micrometeorite hazard etc.

TL17 turbulent edge to field smoothed?

TL18 ? new technology allows (energy dissipation via hyperspace) significantly faster cycle times -> warp drive

Maintenance Rolls

(Maintenance requires the total attention of those whose skills are applied throughout the trip, up to one being per ton of stutterwarp drive can add their skills)

Divide the shift's total stutterwarp maintenance skill level by twice the ships USP size rating. This is used as a mod on the efficiency roll. If the crew wish to play safe they can deliberately reduce the cycle time. For each doubling of cycle time the maintenance roll gets an additional +1.

Unskilled usage can be attempted (at -2) but any success gets treated as normal failure, and chances of mishaps are doubled.

In-system trips

Roll 8 Hourly!

Maintain Stutterwarp Efficiency - Hard (hazardous)

Spectacular success -allows the drive to operate at maximum efficiency. (0.03s/AU)

Normal success - For each number the roll less than spectacular success double the cycle time (& hence half distance travelled).

Normal Failure - average cycle time is 1/min. The trip may be stopped after travelling D6*10% of the journey to service drives & restart as a fresh trip. If the trip is continued the remainder will be travelled at 1 cycle/hr!

Spectacular failure - average cycle time is 2D mins, roll for mishap (see below.) The trip may be stopped after travelling D6*5% of the journey to service drives & restart as a fresh trip. If the trip is continued the remainder will be travelled at 1D hours /cycle!

Interstellar trips

(even at max efficiency interstellar trips will take at least 25 days!)

Instead of rolling for each shift a single roll can be made using the lowest maintenance skill of the vessels crew shifts, in a similar way, but at Impossible difficulty. Each extra parsec beyond the first gives an extra DM of -1. The outcome of this task is handled slightly differently.

Spectacular success - allows the drive to operate at maximum efficiency divided by 1D.

Normal success - Efficiency is maximum divided by (1+1d for each no. the spec. success was missed by)

Normal Failure - average cycle time has dropped to 1/hr divided by 2d - roll for mishap (see below.) The Vessel has travelled 2d% of a parsec. A drive service is required to improve matters, at which point the remainder of the journey can be attempted as a fresh interstellar trip.

Spectacular failure - Catastrophic mishap (or speed drops so low that supplies simply run out.) All crew dead and vessel lost!


Roll 1D

  1. Ships sensors damaged by power surge Easy sensor service of needed to continue (can be carried out by anyone with electronics or sensor skill a routine task taking 4hrs)
  2. An extra 1d hours energy dissipation needed between nanojumps. The field may be kept active or allowed to dissipate as desired.
  3. No additional effect
  4. Drive service required
  5. Random ship location takes 1 hit from micro meteorite.
  6. 1D random locations take hits

Drive Services

Most services can be carried out on-board with a stutterwarp service tool kit (Electronics, & mechanical tool kits together will be a suitable alternative), being mainly adjustments and such like. They must be carried out with the field inactive, with the field activated to check on success. (A normal service is classed as a formidable task, taking 3 hours per attempt.) Once a year the drive should be given a complete overhaul, normally done at the same time as all the other ships systems. It requires a starport with stutterwarp service facilities (Imperial starports will almost never have these.) For each overhaul missed a DM of -2 is applied to all stutterwarp task rolls, and the resulting travel times doubled. Overhaul facilities can be added to a vessel, taking 20 displacement tons, and requiring the use of a model 5 or better computer. Such facilities cost MCr40 and in addition need 3% of the ships drive cost a year as spares/materials. Preparations for the overhaul include growing ultra pure crystals of 'trans dilithium sodium chromate', which has to be performed over a two week period at low temperature in zero G to produce suitably flawless crystals. Growing these from these facilities is an formidable task, during which all drives must be inactive and the facility must be kept gravity free. Three sets of crystals can be attempted simultaneously per facility. Advanced (TL13+) orbital chemical plants will also be able to grow suitable crystals. In storage crystals gradually decay, causing a doubling of cycle time for every year's storage under ideal conditions. Fitting the crystals and carrying out the remainder of the drive overhaul is another formidable task, taking 2 days per attempt. During this time the drive will be totally unavailable for all but the last 2 hours of the attempt (at fully restored efficiency if the task was successful otherwise at the same efficiency as before.


The flying of stutterwarp ships can need considerable skill to control direction. The approach required to handle this is particularly dependant on the local gravity. Unlike normal jump drives stutterwarps can be used within 100 planetary diameters, however the direction of travel is extremely unpredictable under these conditions. It is quite possible to jump into the interior of a planet - this is always fatal and can cause local earthquakes. Using the Stutterwarp drive near planetary surface or other vessels is also severely frowned upon due to the likelihood of collateral damage.

Within 10 planetary diameters

Under such conditions directional control is very crude; each nanojump must be considered separately.

Roll 1d for direction (directions give are relative to 'ahead', the intended line of flight)

Roll Direction of Deviation
1 or 2 None. If rolled as a critical error, reroll as minor deviation.
3 Left
4 Right
5 Up
6 Down

Roll 2d and compare with the table below for degree of error the result can be modified in either direction (after the roll) by up to the pilots stutter pilot skill

Normal deviation

Modfied Roll Angle off indended direction (degrees) Distance off intended line of travel (km) Distance travelled in intended direction
0 or less 1 74.2 4250.6
1 5 370.5 4235.0
2 15 1100.3 4106.4
3 30 2125.6 3681.7
4 45 3006.1 3006.1
5 60 3681.7 2125.6
6 100 4186.6 -738.2
7 150 2125.6 -3681.7
8 180 0 -4251.2
9 120 3681.7 -2125.6
10 110 3994.8 -1454.0
11 90 4251.2 0
12 50 3256.6 2732.6
13 20 1454.0 3994.8
14 10 738.2 4186.6
15 0.2 14.8 4251.2

Minor deviation

Modfied Roll Angle off indended direction (degrees) Distance off intended line of travel (km) Distance travelled in intended direction
0 or less 0.1 7.4 4251.2
1 0.5 37.1 4251.0
2 1.5 111.3 4249.8
3 3 222.5 4245.4
4 4.5 333.5 4238.1
5 6 444.4 4227.9
6 10 738.2 4186.6
7 15 1100.3 4106.4
8 18 1313.7 4043.1
9 12 883.9 4158.3
10 11 811.2 4173.1
11 9 665.0 4198.9
12 5 370.5 4235.0
13 2 148.4 4248.6
14 1 74.2 4250.6
15 0.02 1.5 4251.2

Elsewhere Within 100 diameters

If for any reason navigation is critical treat each single nanojump separately as above but the pilot may use 4 times his skill level as a DM to the deviation roll. Otherwise over multiple nanojumps the deviations will tend to even out.

Roll 6D+6 - pilots skill (minimum 10) for the percentage distance added to the total journey by this meandering. (The pilots multiplier.) This additional distance has to be covered at the rate determined by the drive maintenance rolls for the trip.

In addition a Hard task should be rolled to avoid piloting mishaps (Referees discretion).

Effective speed is as per maintenance roll - pilots multiplier (Don't forget the field generation and dissipation times here!)

Other in system travel

Roll 4D+2 - pilots skill (minimum 5) for the percentage distance added to the total journey by this meandering. (The pilots multiplier.) This additional distance has to be covered at the rate determined by the drive maintenance rolls for the trip.

In addition a Routine task must be rolled to avoid piloting mishaps. (Referees discretion).

Effective speed is as per maintenance roll - pilots multiplier

Interstellar travel

For very long distance journeys where the local gravity is negligible and errors in direction even out to give only a slightly longer route than optimum. No significant hazards are seen from the piloting point of view and most of the journey can be adequately handled by the ships computer.

Roll 3D - pilots skill (minimum 0) for the percentage distance added to the total journey by this meandering. (The pilots multiplier.) This additional distance has to be covered at the rate determined by the drive maintenance rolls for the trip.

(Total Journey time is 25 days * maintenance multiplier + pilots multiplier per parsec)