Some noob questions of travel, speed vehicles metc

[5h4ne]

Apologies if these seem obvious or have been answered before elsewhere.

I'm writing a con scenario where the PCs will hopefully be involved in a "grand finale" vehicle chase across a swamp and through some caverns.

I don't know if I want to bring it down the fine details of how far each vehicle travels in one combast round or whether to have the NPCs "just out of reach."

However I've come out with some figures using my CSE maths which seem about right. I just wanted to run 'em past some people with more practiced left brains than myself to make sure they're ok:

A combat round = 6 seconds

In one round a PCc an move 6 m

in one minute they can move (6x10) 60m

In one hour they can move (60x60) 3600m or 3.6km.


A ground car's speed is 150 kph or 150,000m

In one minute it can move (150000/60) 2500m.

In one round it can move (2500/10) 250m.


Some more questions regarding vehicles:

how fast can a swamp boat travel (i.e a hydrofoil/ a pontoon with an engine etc) either in kph or per round?


How fast does a Far Trader travel? How long would it take to get from a Jumping in point to planetside orbit?

Can an ATV be launched from high orbit like an Air/ Raft?

Thanks all.

 

[Gaidheal]

Well, firstly the 'six seconds' is noted as an approximation but aye, pretty much 'one minute is ten rounds'. A human can move 18m each round (there are three minor actions in a full round and movement is a minor action) over terrain that is not difficult.

Ignoring fatigue and so on, they therefore could move, 'at combat rates', with a groundspeed of around 11 km/h. In reality, personal combat doesn't last hours at a time, for game purposes, so what you actually want is a 'normal' movement rate; I'd suggest 5 km/h with fatigue mounting on an hourly basis (incidentally, humans can potentially hit about 50 km/h at a sprint, though most are going to manage more like 30 km/h IIRC).

150 km/h for a ground car? With anti-grav or something or else a 'performance' vehicle on flat well made roads, maybe so, otherwise, halve it! That might be top speed but with manoeuvring and any kind of less than ideal terrain, there's just no way, really (for reference that's about 95 mph, which is going some even on a typical good road, here on earth).

How far a vehicle moves in a given time depends on what it is doing - specifically, acceleration. If it maintains a constant speed then the speed at the start of your time period can simply be multiplied by the period to arrive at the distance travelled (and for full length journeys you do exactly this - I.E. average speed x time or more often distance / average speed, to find the journey time), if it's accelerating away then it gets more complicated and I mention this because it sounds like it might apply.

For our simple case, let's assume a more reasonable 75 km/h as an average speed; in a minute it moves 1,250 metres, then and 125 metres every round, at that speed.

If the vehicle starts 'at rest' (stationary) we need to know its acceleration ability to decide how far it moves in that turn (only the most pedestrian of vehicle engines is going to be unable to achieve its desired speed in a relatively small fraction of a minute). I'm going to pick an acceleration off the top of my head, as "75 km/h in 3 rounds" which equates to slightly over 4 km/h per second (1.157 m/s^2), we'll say is 24 km/h per round.

In round one, the vehicle is not moving at the start and is moving at the end with a speed of 24 km/h, so the average speed is actually 12 km/h.

In round two, initial speed is 24 km/h and final speed is now 48 km/h, the average being 36 km/h.

In round three we start at 48 km/h, end at 72 km/h and average 60 km/h. For the next round we can assume it moves at 75 km/h for the entire round as the approximation down to 24 km/h per round was our convenience and it's trivial for anything with that kind of acceleration to gain another 3 km/h if it can actually move at that speed at all.

This means that it travelled 20 metres, 60 metres and 100 metres in rounds one, two and three, respectively.

Most small surface boats are going to struggle to get above say 40 to 50 km/h, hovercraft and similar low contact technologies can potentially get much better speeds, though, up to 100 km/h, effectively, quite easily, if they are kept small or else have powerful thrusters of some sort. In / on water, friction AKA drag is a serious limiting factor, whereas a typical wheeled road vehicle has very little to worry about until quite considerable speeds are achieved.

Orbital drops have certain fairly obvious considerations; the ATV's going to be going very fast as it comes close to the surface, even allowing for the atmospheric friction, without some sort of deceleration method. If you do decelerate, it wants to be as late as you reasonably can but it mustn't exceed the tolerance of your cargo or passengers (sustained acceleration of 6 times go [earth standard gravity] is unpleasant to say the least and actually many people will black out, even 4 g0 can't actually be sustained for that long, in reality). If the ATV has some sort of anti-grav drive and some sort of 'inertial dampers' type affair, all that's moot, of course, however, in my opinion that's not in keeping with the spirit of Traveller, in most cases, anyway.

Essentially, with some sort of explanation about drop cradles and the like the above amounts to 'flavour' for the players as they experience the drop - with weapons like the PGMP in the game, assuming an appropriate TL, dropping vehicles from orbit is relatively trivial to do.

Anyway, I hope I've helped rather than simply confused and I'm happy to elaborate, explore further, etc.

 

[5h4ne]

Wow, thanks a lot for the lengthy and very useful reply Gaidheal!

What you have said makes sense and will be really useful if I decide to implement a per round system during the vehicle chase.

I did realise the factors for the listed speed being top speed and acc/ dec but my brain wasn' really up to coping with those until I'd got an idea of the basics.

I've GM'ed quite a few Judge Dredd games (GW rules) and there's detailed (but not too complex) rules for max speed/ safe speed/ acc/dec for all sorts of vehicles. Perhaps Traveller will have this as a supplement. I certainly hope it will be in for the forthcoming Dredd supplement, it's always a big part of my games..

Also, thanks for informing me about the water vehicles and the ATV stuff - it seems some stuff in the core rulebook makes assumptions about peoples prior Traveller knowledge/ is meant to be expanded upon in future supplements/ or assumes people have good scientific knowledge.

Once again, thanks for your time - appreciate it.

 

[Gaidheal]

Mostly, it's a rules-light system, is all and traditionally it's had a very technically inclined player-base, who have no trouble winging such things in a believable manner and / or calculating whatever they really want to know.

If you think I am lying about 'rules-light' try reading the core rulebooks for ICE's RoleMaster ;¬)

 

[Walker]

If you think I am lying about 'rules-light' try reading the core rulebooks for ICE's RoleMaster ;¬)

OWW... My back hurts just with the memory of lugging those books around. Open ended Percentile dice, anyone?

 

[Gaidheal]

Hehehe! I actually like RulesMaster, too. There is, however, no denying its tendency to take simulation to an extreme:

"Hmm, I seem to have failed my Moving Maneuver roll... looks like I'm tripping and falling down the stairs... is there a specific table for the damage?"

"Probably, hang on, I'll check..."

;¬)

 

[Elysianknight]

I wanted to play RulesMaster, but failed my "open book" roll.....

 

[Gaidheal]

That made me laugh, Elysian; so very true ;¬)