Planetoid Armor

[Major B]

I'll do my best to pose this question in a way that makes sense, but may fall short since I'm kind of confused...

The MT RM (page 63) tells me that a planetoid has an inherent armor value of 50 and that buffered planetoids have an armor value of 56.

The same section (updated by errata version 2.16) specifies that, to add armor, subtract the armor mod for inherent armor from the mod for the desired armor value. This means, if I want a planetoid with an armor value of 60 (mod = 190), I subtract 80 (for a planetoid) or 135 (for a buffered planetoid) and multiply the result by (?).

For a normal ship, the hull has a predetermined base cost and weight. Each is modified by the configuration and the type of armor and the result is multiplied by the armor mod value when determining how much armor you want. But, for a planetoid, what to you multiply the mod with? Planetoid hulls have a transport cost and a tunneling cost, but not a base hull cost.

I have an idea on how to solve this omission, but before I post it I'd like to know if there is somethng out there to clarify this. Or, anyone who has hit this snag, please let everyone know how you solved it.

 

[aramis]

Look up the modifier for AV 50, which gives 80.

I want AV 55, which has an armor multiplier of 125.

125-80=45

By armor as if it was mass factor 45.

Standard ship hulls are AV 40, with a multiplier of 33.

 

[Major B]

By armor as if it was mass factor 45.

I understand that part, but in the MT design sequence, you don'y buy the armor. Rather, you multiply the base hull weight and cost by the armor mod.

But what if you don't have a base hull price and weight to multiply by the mod?

 

[E.D.Quibell]

The base weight is from tables 2, 3 or 4 on page 62.

If you have a planitoid it's as stated. If you have a Buffered Planitoid multiply by 1.75.

Those tables also give you the price of the hull, which you don't pay, however if you add armour you need to work out the price with armour and the price without armour and pay the difference, taking into account the type of armour you have available in table 7 on page 63.

Does that make sense?

Regards,

Ewan

 

[Major B]

Those tables also give you the price of the hull, which you don't pay, however if you add armour you need to work out the price with armour and the price without armour and pay the difference, taking into account the type of armour you have available in table 7 on page 63.

Does that make sense?

Yes, and its much simpler than my solution.

Here's my overly complicated method - please let me know what you think.

I started with a 500,000 Td planetoid (not buffered).

Total volume of the entire rock is 6,750,000 kl.

Towing cost is Cr 10 per kl or MCr 67.5.

Weight is 1.0 Tm per kl or 6,750,000 Tm.

Tunneling cost should only be for the volume tunneled, 80% of the total volume of the rock. (5,400,000 kl x Cr 75 = MCr 405).

Now, I want to add armor to AV 55. I won't be plating the exterior of the rock but instead with be adding protection to the interior space (5,400,000 kl). So I get a base hull figure for a 5,400,000 kl or 400,000 Td hull (weight 46,000 Tm and price MCr 166.7).

Since I'm armoring an irregular interior space I use the configuration modifiers for an irregular hull (type 7): New weight is 46,000 Tm x .9 = 41,400 Tm. New price is MCr 166.7 x .5 = MCr 83.35)

The armor type is G (bonded superdense) so the new weight is now 41,400 x .14 = 5,796 Tm.

The armor mod for AV 55 is 123. Subtract the mod for the planetoid's inherent armor value of 50 (123-80) and you get 43.

The new weight is 5,796 Tm x 43 = 249,228 Tm. The new price is MCr 83.35 x 43 = MCr 3,584.05.

Add the armor's weight to the rock's weight before adding the armor and you get a total weight of 6,750,000 Tm + 249,228 Tm = 6,999,228 Tm.

Add the armor's cost to the rock's towing and tunneling prices and you get a final price of MCr 67.5 + MCr 405 + MCr 3,584.05 = MCr 4,056.55.

 

[Major B]

Had to split my reply in half. Here's the rest:

The final weight of the AV 55 planetoid is 6,999,228 Tm.

The final price is MCr 4,056.55.

For comparison, a 500,000 Td standard hull vessel with AV 55 would have the following characteristics (assuming the hull is an unstreamlined cylinder so no configuration modifiers apply):

Weight: 54,000 Tm x .14 (armor type G) x 123 (AV 55) = 929,880 Tm (so the planetoid is about 7x heavier).

Cost: MCr 222.8 x 1.0 (armor type G) x 123 (AV 55) = MCr 27,404.4 (more than 6.7x more expensive than the planetoid).

If the 500,000 Td standard hull vessel with AV 55 had an irregular configuration:

Weight: 54,000 Tm x .9 (configuration modifier) x .14 (armor type G) x 123 (AV 55) = 836,892 Tm (not much difference).

Cost: MCr 222.8 x .5 (configuration modifier) x 1.0 (armor type G) x 123 (AV 55) = MCr 13,702.2 (still more than 3.3x more expensive than the planetoid).

 

[aramis]

The armor is still based upon the total volume... because you're reinforcing the rock-armor, not armoring the individual rooms. Otherwise, the hits would just crush the rooms.

 

[Major B]

The armor is still based upon the total volume... because you're reinforcing the rock-armor, not armoring the individual rooms. Otherwise, the hits would just crush the rooms.

Okay, makes sense.

So it would be a 500,000 Td hull rather than 400,000 Td, but would I still use the irregular configuration modifiers?

 

[aramis]

No, as with the other stuff, when in doubt, in MT, treat a false N/A as the same as a —... (— is actually x1)

 

[E.D.Quibell]

Cost: MCr 222.8 x .5 (configuration modifier) x 1.0 (armor type G) x 123 (AV 55) = MCr 13,702.2 (still more than 3.3x more expensive than the planetoid)

Yes, but you're paying for the Hull as well. You don't see the Hull cost in the asteriod.

I had another read, and my previous post is slightly out.

You need to work out the cost of a normal hull with the armour you want and then work out the cost of a normal hull with 50 armour. You then pay for the difference.

So with your above example an AV 50 hull is 222.8 x0.5 x1.0 x80 = MCr 8,912, so the price you pay for an additinal 5 armour (up to AV 55) is 13,702.2 - 8,912 = MCr 4,790.2

To be honest it would be easier and cheaper to use a buffered planetoid

Regards,

Ewan