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Rogue Trader Navigation: In Details

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Hi guys, main responsibilities of Navigator mostly consists of Warp Navigation and Navigator powers.


Warp Navigation is an important part of Rogue Trader life and I would like to go over specific topics of Navigation like jumping, tracking, pursuing and then to get to Navigator's tricky powers.

For Warp Navigation we are using The Navi Primer rules p.26 "Plying the Warp" - they are great. Still questions from where the jump should be made and how ships should interact in real space and immaterium are not really detailed. 


 Warp travel should be dangerous:
   TNP p.26 "The order to enter Warp space is the most dangerous command a starship's captain can give." (reddit)

 Mandeville points mechanic is used to include ship interaction like chasing, ambushing, blockades and system defenses .

 Ships coming out of the warp must appear some distance away in deep space or risk destruction among the graviton surges in-system. Because of this many civilised worlds have specific jump points marked by beacons to assist in navigation. An ambushing fleet will often lurk nearby, in the hopes of catching a ship unaware.
   Battlefleet Gothic Rulebook, p. 4 

  In order to safely utilize the Warp for travel, one must first travel to a System's Mandeville Point. This is the closest distance that a ship can safely enter or exit Warp Space from its intended destination. If one does not travel to a Mandeville Point, they risk having their Warp jump's direction and navigational calculations interfered with by the gravity of planets and other celestial objects.
   Additional information about Mandeville's points:
    The Path of Heaven (Novel), Chapter 3 
    Vigilus Defiant p.35



First I would like to put details for stellar and warp navigation:

Warp jump duration
To represent the danger and nature of warp routes for Divining the Auguries stage GM gives information about route stability, astronomicon visibility, but duration if path is not charted is generated randomly no matter how far or close the real space point is with TNP Table 2-2.

The duration of the route is given to navigator approximately - days, weeks, months, years - without telling the final number of days: 5 days would be "days of travel", 7 days would be "weeks of travel", 65 days would be "months of travel". It represents the ritual results which are not the real charted route through Immaterium to avoid cheating - like starship crew waiting favourable estimation before jump to uncharted region because it this far better to spend couple 1d5 day tries in ritual to shorten the path on 50 days then spend them in warp.

GM provides approximate duration again after translation and modifing duration with roll on Steering the Wheel. Analyzing the change in approximate durations before and after tranlsation experienced Navigator can decide to continue to navigate warp or risk exiting the warp jump if he feels that warp travel is more dangerous than emergency re-entry to real space.


Mandeville's points
In order to jump ship should travel away from star so gravity tides would not impact the jump and course of warp jump.

To achieve defined distances all system separated on zones correspondent to SoI p.13 The Solar Zones - Inner Cauldron, Primary Biosphere, Outer Reaches - and for each new encountered system numbers of AU randomly generated to define size of each zone and saved for consistency of a gameplay.

Each ship uses it's speed characteristic only in AU for stellar navigation which represents constant accelaration and deacceleartion for travel in real space. It will give each captain understanding how much time he will spend to jump point or from it to planets in system. The topics of jump not from Mandeville's point are always lurking around so we defined that it is possible but hard to do and each zone closer to star presenting  -10 penalty to Navigation(Warp) providing from -10 modifier to jump from Outer Reaches to -30 to jump from Inner Cauldron and summarized penalty of -60 if jump is originated from Inner Cauldron and destination point is also in Inner Cauldron.

Now, there are mechanic available to play with such things as trajectory of the ship to lay ambushes and mine fileds, time in real space to chase the ship or distance to track and sabotage it.


Fleet warp jump
Leading Navigator navigate through Immaterium, navigators on following ships steering ships to stay around leading ship. To avoid encounter only leading navigator rolls on encounter and leading pilot rolls for test to avoid encounter.

  • Number of ships Navigator is able to lead depends on Navigator WP bonus: (Calculated as number of ships started from WPB*(WPB+1) )

           WPB       Number of Ships

           1            2
           2            6
           3           12
           4           20
           5           30
           6           42

  • Fleet provides fleet size penalties for Navigator for Navigation(Warp) because it is harder to navigate through warp safely for a fleet: (Calculated as https://en.wikipedia.org/wiki/Factorial )

           Penalty      Number of ships

           0                 1     
           -10              2   
           -20              6   
           -30              24 
           -40              120
           -50              720 

Ship tracking

There are great Navigator powers Track in the Stars and Obliteratng the Immaterial Wake to track and hide ship tracks correspondingly in real and warp space by faint trail of warp drive.


  • Tracks in the Stars

      When Navigator see tracks he can identify warp drive and type or class of the ship by specific to each warp drive faint as technician on submarine sonar can identify different types of vessels or specific vessel ecnountered before by it's sonar echo characteritics. Navigator can distinctively separate tracks and identify tracks he encountered previously. While the radius is not stated for this power we decided that it can cover whole system, but actual time to investigate all ship tracks depends on system size and traffic. If there are many ships it would be hard to find specific ship without additional information, or to track what happened on battlefield months ago and it could take hours and hours of investigation and tracking.

      Tracking in real space:
      If Navigation(Stellar) roll is successfull then you tracked (1+DoS) * Perception Bonus AU. If roll is failed then you at the same place spending DoF days on investigation, if number DoF > PerB then you cannot read the trail and continue tracking. If pursued ship still in travel it is possible to chase it and find it in space as Psyniscience Test at Perception Bonus AU ahead in already tracked path.  

      Tracking in warp space:
      On Divining Auguries the number of DoS discovers the (1+DoS) * Perception Bonus days of original warp route.
      If original warp route equal or less than divined length then you can predict where the path is leading without transalting to warp based on power description. Weeks old trail - shows exact place in destination system, months old trail - shows just a destination system, years old trail - shows just a destination sub-sector.  If divined length is less than full number of discovered by this test days it means that path is going just that far in warp, which could mean that ship is currently flying through warp or destroyed somewhere there. 
      When you translated Navigation(Warp) successfull roll on Steering the Wheel means that (1+DoS) * Perception Bonus days of original warp route tracked. If it is failed then you at the same place spending DoF days on investigation, rolling Warp Encounter once. If number of DoF  greater than Perception Bonus of Navigator then he cannot read the warp and continue tracking. If pursued ship still at Warp Jump it is possible to chase it with superior warp speed and navigation and find it in Warp as Psyniscience Test in Perception Bonus days ahead. You can follow it or start combat in Warp Space.

  • Obliteratng the Immaterial Wake

       There is only one thing to add - Navigator can do only Obliteratng the Immaterial Wake or Track in the Stars but not both at the same time. Same for navigation in the warp and Obliteratng the Immaterial Wake at same time - one Navigator can't do both simultaneously.


I've started with two Navigator powers and now just continue with remaining I wanted to talk about:

  • The Course Untravelled

       It is not a true teleportation. Paradox of closed door - lets suggest that physical position can be altered by searching alternative current in which Navigator got inside before door was closed. ****!!! Also how long ago it could be opened - days, months, etc - time is limited and Navigator can do this only for duration of the current Turn he is in and not even previous one: if entrance is collapsed behind Navigator can't get outside - chosing alternate future needs time and Navigator should be in this state as little as possible. (Alternative future takes time)

      Navigator can't get to any location if there is any test involved. Deducted from description and generalized - "could have walked, climbed, or swam there normally without impediment.". Closed door even a weak one is also a "no go".

      Only one use per Turn. Restricted version of Master level description "perform this power as a Free Action or as a Reaction". Navigator should choose either to use it on his Turn as Action OR leave it for Reaction - to eliminate possible usage as appearing at enemies midst, using Lidless Stare and then disappearing on Reaction. It might be cool and tempting, now calculate how many PC's in party will survive if enemy NPC Navigator will do this on Master level.


  • The Lidless Stare 

       If Navigator casts Lidless Stare on another Navigator or another one is happened to be in a radius during cast and didn't get out of it they automatically start a duel TNP p.41.


  • Tides of Time and Space

       Combat rules strongly suggests that only reactionary actions should be made out of your Turn, so the version that it can be casted at the beggining or in any moment of Combat Round was not viable. If Navigator is doing this on his Turn it won't actually changing his initiative order on that Turn and power is not sustainable. So, it was ruled that it is used on Navigator's Turn and Action duration bonus is applied on the same Turn, but intiative changes will be applied in the next Round.


  • Disrupting the Empyrean

       Counts as an extended action in starship combat for Navigator, can be sustainable as long as Navigator called to sustain it each Turn.
       In order to connect Pilot(Space Craft) test to this power description which gives us details ITS p.189 "creating something akin to a miniature warp stormin local space." it is counted that each ship entering or exiting warp should use Navigator rules for avoiding warp encounter "Warp Storm" TNP p.21 with Pilot(Space Craft) test involved.


  • Stacking the Deck

       Counts as an extended action in starship combat for Navigator.

That's all for today. I'm working for quite some time on Mass Ground battles full detailed rework, hope it will be next.


Kind Regards.

Here about who, what and why.

Edited by rt1234456

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