T5 Armor Layers and Planetoid Hulls

[marginaleye]

Can somebody explain how armor for starships works in the T5 design rules?

I'm trying to design a ship with a Planetoid, i. e. Hull Configuration = P, hull.

As I understand it, ships with Planetoid Hulls automatically have Hull Structure = FeN, and thus use FeN Armor Layers.

The Armor Value of an FeN Armor Layer is 20. That's actually a lot *better* than a standard Plate Armor Layer, whose Armor Value is equal to the Tech Level of the ship.

Each Armor Layer (regardless of type) after the first requires 4% of the total volume of the ship's hull.

Here's what's puzzling me: In the Classic Traveller "Book 5: High Guard" design rules, the protective value of a planetoid hull came at a rather heavy price -- the loss of 20-35% of the ship's total volume (depending on whether you wanted a regular planetoid hull, or a sturdier "buffered" one). I've looked and looked, but haven't been able to find any similar penalty in the T5 design rules.

Am I missing something? This seems broken to me. I checked the "T5 0.9 Errata Review" PDF, and didn't find anything there. I find it very hard to believe that (a) a cubic meter of natural nickel-iron planetoid offers better protection than a cubic meter of carefully designed and manufactured hull, and that (b) there's no minimum amount of space within a planetoid ship that must left "un-carved and un-tunnelled" for the sake of preserving structural integrity.

 

[AnotherDilbert]

No, I don't think you are missing anything. There's no structural tonnage specified that I can see.

Note that Unstreamlined ships can also use FeN structure.

 

[agorski]

Can somebody explain how armor for starships works in the T5 design rules?Each Armor Layer (regardless of type) after the first requires 4% of the total volume of the ship's hull.

Here's what's puzzling me: In the Classic Traveller "Book 5: High Guard" design rules, the protective value of a planetoid hull came at a rather heavy price -- the loss of 20-35% of the ship's total volume (depending on whether you wanted a regular planetoid hull, or a sturdier "buffered" one). I've looked and looked, but haven't been able to find any similar penalty in the T5 design rules..

You can just keep adding layers until you get to the 20-35% of hull used and have awesome armor protection. T5 apparently just gives you more granularity in controlling the volume.

The thing that bugs me is that anti-layers make no sense with a planetoid hull. You're not likely to lay down a new layer of FeN with special properties if this is emulating a hollowed-out asteroid. External coating is fine, though.

 

[marginaleye]

In practice, this isn't that serious a problem since planetoid-based ships should be pretty rare.

Every nickel-iron planetoid is going to be different. They'll differ in size, shape, and precise metallurgical composition, and each one will have its own unique fissures, fractures, and other hidden irregularities (all of which will have to be taken into consideration when planning how to carve out internal spaces and mount drives and other equipment).

Navies and shipping companies thrive on standardization, and having a significant number of similar-but-not-identical planetoid-based ships would be an ongoing logistical and administrative headache. There are some plausible niches for planetoid-based ships (e. g. disguised system defense monitors), but they're probably not sufficiently common that the failure of the starship design rules to handle them properly is a particularly serious problem.

 

[Condottiere]

You'd think so, until you do a cost benefit analysis.

You can also take a laser drill to shave off tonnage to a more desired weight.