Prev: Re: [DS] Stargate Next: Traveller FT/DS/SG

# Re: (FT) beta variable hull rows

From: Oerjan Ohlson <oerjan.ohlson@t...>
Date: Thu, 10 Jun 2004 21:16:44 +0200
Subject: Re: (FT) beta variable hull rows

Glen Bailey wrote:

>Steve is back in town so its ship designing time and lots of FT combat
>for nearly two weeks.	While designing new ships, and seeing the
>advantanges in combat of warships only having 3 hull rows, it seems to
>me that the cost 3-row designs is too cheap at 3 per hull box.

This time I hope that you have tracked (or will do so, if you haven't
played the games yet) all dierolls etc. so you're certain that it isn't
just Steve's luck with the dice acting up again?

(No, I'm not being sarcastic. I just know far too well what effect a few

extreme dierolls during the first playtest can have on the impression
the
players get from new rules, and from what you've posted about yourself
and
Steve you both seem to get more than your fair share of extreme
dierolls.)

>It's literally a "no-brainer" to make all new designs with 3 hull rows,

As you'll see below, it isn't quite as straight-forward as that...
whereas
your suggestion to increase the cost of 3-row hulls to 4 pts/box would
make
it a no-brainer to stay as far away from the 3-row hulls as possible :-(

>and mathematician Steve immediately went to 3-row hulls on his ships.
You
>would think that a 50% increase in hull price would have some effect,
but
>it isn't actually 50%, more like 33% if you take the cost of the
initial
>hull cost into the equation (4-row: 1+2=3, 3-row: 1+3=4).

It is neither 50% nor 33% more expensive; you've forgotten to take the
cost
of the hull boxes' proportion of the ship's FTL and sublight engines
into
account. In the *Fleet Book* design system, which is what you're using
above (since you use a flat 1 pt/Mass cost for the "basic hull
structure"),
the 3-row hull is only some 20-25% more expensive per hull box than the
4-row hull is depending on what engines the ship has.

>I think the price of 3-row hulls should increase to 4 per box.
[...]
>Or is this new-fangled combat cost rating system I hear rumors about
>going to take this into account?

The combat cost rating system you're currently using already does take
it
into account (and if Steve had done his maths all the way through he
would've realized that;  the calculations are quite straight-forward).
FWIW
the "new-fangled" points system (ie. the CPV system) complicates the
issue
a bit; I'll discuss that at the end of this post, but
until I say otherwise I'll be talking about the *Fleet Book* (NPV)
design
system that you're currently using:

For an average thrust-4 FTL-capable human ship, each hull box @ 1 Mass
requires its own "basic hull structure" (the "+1 pt" you included
above),
PLUS 1/7 Mass of FTL drive (which costs 2/7 pts for itself and an extra
1/7
pts for *its* basic hull structure), PLUS 2/7 Mass of sub-light drive
(which costs 4/7 pts for itself and an extra 2/7 pts for *its* basic
hull
structure). The "hidden extra cost" of each hull box on this ship is
therefore 1+2/7+1/7+4/7+2/7 pts, which rounds to 2.3 pts. IOW, for
thrust-4
FTL-capable human ships the last paranthesis of the above quote
should've
read: "(4-row: 2.3+2 = 4.3, 3-row: 2.3+3 = 5.3)".

For ships with other engine combinations these value will be different,
but
the overall cost ratios between the hull types remain pretty similar as
long as you compare ships with the same engine combinations. Ie. the
below
argument holds just as well for them as it does for the thrust-4 ships,
so
I'll use the numbers for thrust-4 FTL-capable ships below.

For a ship with this above engine combination, a hull with 4 boxes in 4
rows - ie., 1 box in each row - have a total cost of 4*4.3 = 17.2 pts.
*3*
boxes in a *3*-row hull - again 1 box in each row - have a total cost of

3*5.3 = 15.9 pts on this ship.

If you make the 3-row hull cost 4 pts per box instead, each 3-row hull
box
would have a total cost of 2.3+4 = 6.3 pts; so the 3-box, 3-row hull
would
cost 3*6.3 = 18.9 pts.

This is *more* than the total cost of the *4*-box, 4-row hull, so what
you're actually saying with this proposal is that you believe that the
4th
box in its 4th row is worth *less than zero points*. In other words,
you're
saying that a ship with 4 rows would become *more powerful* if you
replaced
its 4th hull row with the same Mass of empty cargo holds without
changing
anything else on the ship.

Note that I'm not saying "more cost-effective" or "more powerful for its

points value" or anything like that, but a straight "more powerful" -
which
means some combination of "more firepower", "better at applying the
firepower carried" and "harder to destroy". Since replacing the 4th hull

row with empty cargo holds changes neither the ship's firepower nor its
manoeuvrability (ie. ability to apply its firepower), the only thing
"more
powerful" could mean in this case is "harder to destroy".

In my experience ships with 3 rows of X hull boxes (for a total hull
integrity of 3*X) are *not* harder to destroy than ships with 4 rows of
X
hull boxes (for a total hull integrity of 4*X) but otherwise identical
equipment. Quite the contrary, in fact; in my experience 3*X-hulled
ships
are almost invariably *easier* to destroy than 4*X-hulled ones simply
because it takes X fewer damage points to destroy them.

Of course 4*X-box, 4-row ships aren't very *much* more powerful than
3*X-box, 3-row ships with the same weapons etc.; by the time they've
taken
3*X pts of damage they have usually lost most of their weapons etc. so
their remaining combat power is very low.. but the 4*X-hulled ships are
nevertheless more powerful, because the 3*X-hulled ships would be
*destroyed* - ie., have *zero* combat power left - after taking 3*X pts
of
damage. In the NPV system adding a 4th hull row to a 3-row ship (with
thrust-4 and FTL, that is), ie. increasing its number of hull boxes by
33%,
effectively costs

[total cost for 4 boxes in 4 rows] - [total cost for 3 boxes in 3 rows]
=
17.2-15.9 = 1.3 pts

per new 4th-row hull box. This isn't very much, which seems appropriate
considering how bad a shape the ship will be in by the time the presence
of
the 4th row becomes important; but it is more than zero.

***
Now, all of the above was about the *Fleet Book* (NPV) ship design
system,
with its flat 1 pt/Mass cost for the basic hull structure. In the *CPV*
system the cost for the basic hull structure depends both on how large
the
ship is and exactly what it is equipped with, so adding extra hull boxes
to
form a 4th hull row on a ship which previously only had 3 hull rows will

increase the cost for the basic hull structure for each Mass of the ship

because its TMF increases.

The result is that if you use the CPV systems 3-row hulls are more
effective on large capitals than they are on cruisers or escorts do, and

5-row hulls are more effective on small ships (provided that they have
at
least 5 hull boxes, that is) than on large ones; and similarly ships
with
high thrust ratings tend to gain more from using 3-row hulls than ships
with low thrust ratings (and low-thrust ships gain more from using 5-row

hulls, etc.).

This *could* turn out to be a balance problem. *So far* I haven't found
it
to actually be one; IME those ships which are large enough to benefit
overly much from using 3-row hulls instead of 4-row ones are also so
large
that the CPV system starts making them prohibitively expensive anyway,
and
for smaller ships (which tend to have higher thrust ratings than the
larger
ones) the effect that small ships gain relatively less from 3-row hulls
tends to balance out against the effect that high-thrust ships gain
relatively more from them. Testing continues however, and I'd be
grateful
for any detailed battle reports pitting 3- and 4-row ships with various
thrust ratings against one another.

Kind regards,

Oerjan
oerjan.ohlson@telia.com

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

 Prev: Re: [DS] Stargate Next: Traveller FT/DS/SG