Transport capacity

I was looking at the DS2 vehicle design rules last night, trying to come up
with a conversion factor for that accounts for the different weights of
vehicles of similar size.

I noticed that the BVP (Basic Vehicle Points) is the total of the vehicle's
capacity plus an additional 20% for each level of armor. It is this value
which is used for calculating the cost of the power plant, etc.

If we take this as our rule of thumb for calculating vehicle mass, then a size
5 AFV with level 5 armor would have a BPV of 50. If we follow the convention
that the largest normal sized vehicle is equal to one FB mass point, then the
conversion rate would work out neatly to 2 metric tonnes per BPV point.

Using this conversion rate, the tonnage ranges for vehicles of up to size 7
are:

Size 1 - 10 to 12 tonnes (13 with reactive/ablative armor)
Size 2 - 20 to 28 tonnes (32 with reactive/ablative armor)
Size 3 - 30 to 48 tonnes (57 with reactive/ablative armor)
Size 4 - 40 to 72 tonnes (88 with reactive/ablative armor)
Size 5 - 50 to 100 tonnes (125 with reactive/ablative armor)
Size 6 - 60 to 132 tonnes (168 with reactive/ablative armor)
Size 7 - 70 to 168 tonnes (217 with reactive/ablative armor)

These numbers seem pretty close; here are some example vehicles:

M1 Abrams - 63 to 69 tonnes; size 4/armor 3-4 (?)
Hammer's Slammers tank - 170 tonnes; size 7/armor 7 (?)

One problem with this conversion rate is that it conflicts with the
"8/5ths
rule" for the capacity requirement for carried vehicles. If this concerns you,
I recommend reducing all of the above tonnages by (vehicle size x2) tonnes.

In other words, an unarmored vehicle would weigh (vehicle size x8) tonnes.
Each level of armor would add (vehicle size x2) tonnes for regular armor and
(vehicle size x3) tonnes for reactive or ablative armors. Note that
only unarmored vehicles would meet the "8/5ths rule" as written.

Also note that I did not reduce the weigh of the armor, just the vehicle
chassis. This is to avoid fractional accounting, but if one needs a PSB
explanation, assume that the extra mass is due to the need for a larger
powerplant.

Using this conversion rate, a size 1 vehicle would weigh 8 to 10 tonnes with
regular armor and up to 11 with reactive or ablative armor and a size 5
vehicle would weigh 40 to 90 tonnes with regular armor and up to 105 tonnes
with reactive or ablative armor.

Note than in both cases, this conversion rate provides some encouragement for
a "quantity vs. quality" strategy; a single FB mass point of cargo capacity
could be used transport a single heavy tank or up to 10 or 12 smaller
vehicles.