Warp drives in a jump drive universe. A Traveller challenge

This is an edited version of something I posted on Facebook but belongs here as well:

Up to recently, I have basically run the travel systems on a plot-based mechanic. i.e. things break when it drives the plot for them to do so. But I have had some pressure from players to actually set the systems to paper as it were so they can run their own stories in my universe. So I have been working my original notes into something Traveller friendly to that end.

What I have so far sounds good in my own head but I thought I would take advantage of our hivemind to see if makes sense to others or if there might be better ways of handling some elements. All I ask is that questions and discussion focus on these elements not on why you think warp drives “break” the game since I will humbly contend that I have hundreds of play hours proving it does not break the game.

First step

Warp drives are rated in a similar fashion to jump drives in that the rating expresses how far the drive can travel in one week. The major difference is that while both drives can be used to travel less than their rated distance a warp drive’s travel time is in fractions of its rating since it is not locked into a jump transit. For example, a W4 engine can make a 2-parsec transit in 3-4 days rather than a week.

The displacement of warp drives vs jump drives is similar with the warp bubble generator being larger than the equal jump drive but balanced out by requiring lesser fuel tankage so for simplicity's sake I treat them as a 1 for 1 displacement for building purposes. The warp drive is essentially two parts with a power supply and a warp generator. The power supply can be upgraded to the next rating but that does not move the drive to the next stage but rather becomes important when figuring overdrive problems.

Second step

Warp drives can be overdriven by one or two stages for limited amounts of time. W4 can run either W5 or W6 Overdriving an engine by one stage will require two malfunction checks to be performed weekly and an overhaul of the drive system to be performed afterward costing 50,000 cr per step of the rated engine. Failure to perform the overhaul means that any further overdrives are done at a penalty for each week running overdrive subsequently. (the overhaul resets the counter to zero as it were).

Overdriving an engine by two stages means the malfunction checks are made daily with a similar cumulative penalty and the overhaul cost is doubled.

There are two malfunctions related to overdriving a warp engine One is related to the power source and the other to the warp containment.

The power malfunction is called a cascade breakdown. If this occurs the SOP is to shut down the power unit and check to see if it stops. If it does not stop then the power unit must be ejected as it will eventually build to an explosion that will gut the ship.

If the shutdown is successful then it may be used at a reduced capacity. (drive rating minus 1d6) If the new rating is 0 to -2 then the effective rating is W1, -3, or lower and the power unit can no longer sustain a warp bubble and it is time to break out emergency beacons. Either way, the power unit must be replaced to restore the drive rating of the ship. ($$$$)

This can be reduced by an upgrade of the power unit to the next larger rating. While it does not allow the drive to go faster it pushes the test for a cascade breakdown back one step. With an upgrade power unit, one-stage overdrive does not require the cascade check and a two-stage overdrive need only be checked for overdrive malfunction once a week. This does not affect the other malfunction calculation though.

The other malfunction is less understood but closely related to the warp containment unit. It is referred to as wink out. It is not a rupturing of the warp bubble but manifests something like a misjump. The bubble collapses and displaces the ship in a random direction up to twice the rating of the drive. Aside from the fact that a number of systems will be damaged such as communications and navigation which will need to be repaired the effective drive rating is immediately halved until the warp containment can be repaired properly. ($$$$$) at a class B port or better.