Prev: Re: [FT] Truth is stranger than the Tuffleyverse Next: Re: [FT] Truth is stranger than the Tuffleyverse

Re: DS2 Questions

From: "Oerjan Ohlson" <oerjan.ohlson@t...>
Date: Sun, 14 May 2000 13:17:25 +0200
Subject: Re: DS2 Questions

Graeme, you seem to have missed the underlying reason for my DSII
questions: I'm revising the entire DSII vehicle design and points cost
system, because the current one doesn't work. This revision is by no
means [OFFICIAL], of course.

The fact that I am revising it means that your use of the *current*
points costs of various systems to describe why my suggested *modified*
systems won't work or balance is... not very meaningful. The costs of
the modified systems are after all highly unlikely to be the same as
the cost of the current systems :-/

Graeme Bradbury wrote:

>>GMS are *already* affected by ECM, and Superior ECM is much,
>>*much*, *MUCH* more common among the DSII designs I've seen >>(both
IRL and on the web) than level-3 Stealth is. Level-3 Stealth >>degrades
direct fire against Size-4+ targets (you can't get a smaller
>>signature than 1) by very nearly the same factor as Superior ECM
>>degrades GMS fire against any target.
>>Since Superior ECM is common and Level-3 Stealth isn't and they
>>both have the same effects against their respective "target" weapons,
>>you seem to be saying that infantry is dog food in the *current*
>>since they don't have any long-ranged anti-tank weaponry... or?
>On a size 4 tank superior ECM reduces the chance of being hit by
>between 22.5% and 30%.
>Level 3 stealth reduces the chance of being hit by
>between 12.5% and 25%. 
>So not only is it less effective it is also more than FIVE times more

First, this is exactly the reason why Superior ECM is very common and
Level-3 Stealth isn't in the current system. The points costs in the
current system have no relevance whatsoever to the totally-revised
system I'm working on.

What you said was that I risk to "turn GMS into a direct fire weapon
that is also affected by ECM, which means infantry turn into dog food
since they now have no long ranged anti-tank weaponry."

Ah, OK - if you thought that the GMSs would be degraded by *both*
Stealth *and* ECM effects, this comment makes sense. That was never in
consideration; the combined Stealth/ECM system would work as the
current ECM vs GMSs and as the current Stealth vs direct-fire weapons.

Second and more importantly, you're looking at the wrong figures. The
*absolute* reduction in the enemy's hit probability (ie, the difference
between hit rate A and hit rate B) is irrelevant for the value of a
defensive system; what is important is instead the *ratio* between the
two hit rates (or, conversely, the percentage increase of the shots he
needs to fire to achieve one hit). 

Which is better - a system which increases the number of shots you need
to fire to get on average one hit from 4 to 8, or the one which
increases the number of shots from 1.33 to 2.22? The first reduces the
enemy's hit probabilty from 25% to 12.5%, while the other reduces it
from 75% to 45% - but the enemy must fire twice as many shots to
compensate for the first, while he only needs 5/3 as many shots to
compensate for the second.

Looking at the relative modifications in hit probabilities for Level-3
stealth on a size-4 vehicle, we find:

D12: From 71% to 46%, ie by 100-46/71 = (1-46/71)*100 = 35%
Or, conversely, the vehicle just had its chance to survive the shot
increased by (71/46-1)*100 = 54% (ie, the enemy has to fire on average
54% more shots at it to hit it).

and in the same way:
D10: 41% (the enemy needs to fire 71% more shots to get a hit)
D8: 48% (93% more shots)
D6: 50% (100% more shots)
D4: 50% (100% more shots)

The Superior ECM reduces the hit probabilities of Basic, Enhanced and
Superior GMS guidance by 56%, 49%, and 40% of the chance of hitting a
target without ECM. It is a little better than Level-3 Stealth against
Basic GMS guidance, but very close (as in "too little to show up in
playtests" against Enhanced and Superior GMS guidances. Even its higher
power against Basic guidance compared to the effect of Level-3 Stealth
vs Basic FCSs, is small enough to be very difficult to see even in
intensive playtests.

> A tank can also obtain poor mans stealth. ie. Hide in a
> Evasive driving, digging a hole and hiding in it. All of which are
> cheap. (except for digging the hole)

Sure it can. However, the stealthed tank gets very nearly the same
relative benefit from cover or evasive maneuvers - eg., if a Signature
4 tank goes hull down a shot from say a D10 FCS (choose FCS quality and
range to match) has its hit chance reduced from 65% to 39%, ie.   
(1-39/65)*100 = 40%; if the tank was Signature 1 instead the enemy hit
probability goes down from 38% to 24% which is (1-24/38)*100 = 37%. The
difference between being 40% harder to hit and being 37% harder to hit
rather small; in both cases the enemy needs to throw on average about
60% more shots at the hull-down tank to get a hit than he would need if
the tank was in the open.

The relative effect of a secondary die depends surprisingly little on
what primary die you use (at least it surprised me to find the two
almost independent!). It depends quite a bit on the *opposing* die, but
that should be factored into the value of the enemy FCS rather than
into the defensive system or tactic providing the secondary die.

>But the only poor mans ecm is an ADS vehicle, a PDS or popping >smoke.
>The ADS is very expensive and variable compared to how many people
>want you dead. 

The ADS does seem to be overpriced, yes. That's one of the bits I plan
to revise.

>A PDS is very very expensive since it takes not only points but space
>as well. 

Again I wish to remind you that I am *revising* the design system. The
PDS is BTW somewhat more effective than the corresponding level of ECM,
though not enough so to justify the higher internal capacity cost.

>And smoke only protects from frontal fire. 

Smoke, OTOH, is completely free, stops GMSs from being fired through it
completely, and all vehicles have it. 'Course, the DSII smoke rules
don't reflect current use of AFV smoke grenades very well - eg, firing
them in response to ATGM ambushes :-/
>>First, combining Stealth and ECM into one system (with 4 or 5 levels,
>>including "None" and maybe "Brilliant") *reduces* the number of
>>combinations compared to the current situation. In the published
>>ECM has 4 levels and Stealth has as many levels as the vehicle's
>>class, and these can be combined any way you like - eg., for a Size-5
>>vehicle there are 20 possible combinations of ECM and Stealth. Last
>>time I checked 4 and 5 were both somewhat smaller than 20 ;-)
>You are forgetting Size in your calculations. IF a GMS system is
>defended against by "defence"(size modified by a combined
>stealth/ECM) + PDS and a direct fire weapon is defended against by
>"defence" + "mobility" or "terrain". And ECM IS NOT an integral part
of >the chassis. Then there are 30 levels to balance. (Since each size
will >have a different multiplicative cost due to greatly differing

30? You're taking size-6 vehicles into account as well?

Again you seem to be looking at the *absolute* changes in hit
probabilities. As I wrote above you need to look at the *relative*
changes to get any useful data, and when you do there are four (or
five, with Brilliant ECM) distinct groups (which I called "cases"
above). Yes, each group has some small variations within itself, but
again these variations are too small to detect even in intensive
playtesting. I listed these four (five) cases in my recent reply to
David Brewer.

So no, I'm not forgetting size. Indeed, it was my study of how
important size was which got me thinking of combining Stealth and ECM
in the first place... and just as I've been told for other
applications, it turns out that for the cost of Stealth/ECM systems
size isn't very important. It's how you use it which matters <g>

>If on the other hand ECM IS an integral part of the chassis.

This is completely out of the question and has never been considered.

[on lo-mob wheeled vs faster]

>>Interesting. Given his relatively low mobility, is he able to hold
>>range open for long enough?
>We play on a 6 by 4 table starting on the short sides. So he tends to
>get a reasonable few licks in before i get close. Mainly by

OK. Sounds like fairly open terrain?

>His main problem is not the shooting nitty-gritty stuff, but the fact
>his tactical options are so limited. He has to spread out enough so
>arty don't get the whole force but still keep close enough that he
>get picked off bit by bit. (Air-dropped mines totally scupper him)

<chuckle> Yes, I can imagine that...


Oerjan Ohlson

"Life is like a sewer.
  What you get out of it, depends on what you put into it."
- Hen3ry

Prev: Re: [FT] Truth is stranger than the Tuffleyverse Next: Re: [FT] Truth is stranger than the Tuffleyverse