[Spaceships] Armor Density

[RyanW]

So I've been debating whether these two house rules were too complicated, since they require logarithms, cube roots, and all kinds of other nasty things. So I started simplifying the math. It now features only multiplication, addition, and comparing to a chart. It can be done on a $1 calculator, or very quickly on paper.

And what's best of all: the results are perfectly identical.

First of all, some quick terminology: Heavy armor means steel, iron, or orichalcum. Light armor means ice, wood, or etherwood. Medium armor means pretty much all other armors. Roomy systems are those that have substantial empty spaces, such as habitats and hangar bays, while extremely roomy systems are those that are almost entirely empty space, such as open spaces. If using the smaller subsystems rule, treat a smaller system as 1/3 or 1/2 of a system.

Get the secret number by adding 9 times the number of heavy armor systems and 7 times the number of medium armor systems, then subtract 10 times the number of roomy systems and 30 times the number of extremely roomy systems. Remember this number: You'll need it later.

A lot of armor makes a ship smaller, increasing armor thickness

Look up the secret number on the chart below. If it falls between two rows, use the row above. The result is the multiplier to all dDR (including that of light armor, even though it doesn't contribute to the secret number).

Number	Multiplier
-600	0.6
-554.67	0.7
-287.67	0.8
-131.67	0.9
-34.67	1.0
28.66	1.1
72	1.2
102.5	1.3
124.66	1.4
141.33	1.5
153.66	1.6
163.33	1.7
171	1.8
177	1.9
182	2
185.66	2.1
189+	2.2

A lot of armor makes a ship smaller, decreasing target area

As before, look up the secret number on the table below, using the row above if you fall between. The result is the reduction of SM for combat purposes.

Result	SM Change
-600	+1
-163.33	0
92	-1
172.66+	-2

Special case: Exotic materials

Exotic laminate can be any of a number of different hypothetical ways of making super tough materials. Depending on the exact technology in the setting, this could be a light, medium, or heavy armor, or an even more dense super-heavy armor. If the latter, multiply the number of subsystems by some higher number when calculating the secret number. 9.5 would be as dense as lead, 10 would be as dense as gold or osmium, and 10.5 is exotic collapsed matter of effectively infinite density.