Hull thickness (starship design)

[alveric]

Quick question, throwing it out to the crowd for discussion, like.

I know that I - like most people - design starships using a pen, a ruler and some squared paper. I am now trying to apply some proper technical stuff, to make my ship a bit more like home for the group (eg. passages are about 1m wide not 1.5m wide, heavy-duty bulkheads between compartments are 15-30cm thick and standard internal partitions are about 2-10cm (depending on whether there are ducts between them for air circulation, water or power)).

Traveller ships tend to use fuel tankage as "filler" between the inhabited compartments and the outer hull, certainly in many of the canon ship designs.

But how thick do you think the hull is? If I wanted to drill a hole from outside a ship, how far would I have to drill before breaching either fuel tanks or an inhabited compartment?

Would appreciate some thoughts on it - are there any real navy people out there who can comment on this sort of thing (subs?) without being naughty?

Many thanks,

A.

 

[DFW]

Would appreciate some thoughts on it - are there any real navy people out there who can comment on this sort of thing (subs?) without being naughty? Many thanks,
A.

It depends on how advanced you think metallurgy is in the Trav universe. Food for thought: At top speed (point of turn around to decelerate) from Earth to Saturn (average distance) at 6Gs, a ship will be travelling ~9160 kilometers/sec. Running into a 1 gram micrometeorite at that velocity produces ~41,952 MJ. To put this in perspective, the 120mm main gun of an M1 MBT firing a DU penetrator, produces 9 MJ of kinetic energy at the muzzle.

So, the outer hull is either made out of metal we are familiar with and is a couple meters thick or, it is very advanced so it can be MUCH thiner. If the latter, your internal bulkheads are going to be a few cm thick, not 15-30cm. I know the thickness of some sub hulls but, that info is of no help as they are as soft as butter when comparing against what a spaceship hull MUST be.

 

[Andrew Boulton]

Depends how well armoured it is, and what it's made of.

Using TNE values, civilian ships are ~1cm, small military ships are ~2-10cm.

 

[Brian Blank]

IMHO I'm thinking you would have a layered hull. This is going from inside out

Inner Bulkheads
piping/wiring runs
insulator-
Inner hull/pressure shell 2-5cm thick
Insulator- 2cm thick
Jump Grid
Thermal Protection system / Armor

Total about 15cm to 18cm more likely thicker

 

[Brian Blank]

Ok, amending my last post.
Just took a look at photo of the hatch for Space shuttle Discovery. That is at least 12 -18 inches thick (30cm-45cm) including the TPS tiles. Might be just about right for a Merchant hull.

 

[Icosahedron]

Well, I have no inside knowledge of RL systems, but many years ago I figured the following, using CT:

According to Striker, unarmoured ship hulls have an armour factor of 40, and since for a target the size of a ship, I reckon slope has a negligible effect, so this equates to a thickness of 2.5cm for Bonded Superdense plating.

However, I figured the ships would have a layered armour system, and that the gap between the layers would probably be more important than the metal thickness in determining the overall thickness of the hull. Also, on larger ships even BSD wouldn't be self-supporting, and space would be needed for structural bracing between the hull layers.

Therefore, true to my CT roots, I generated a quick rule of thumb (with lots of exceptions). As a guide, I took overall hull thickness to be the exponent of the displacement. ie, small craft have hull thicknesses between 0.1 and 1 metre, ships in the hundreds of tons are between 1 and 2 metres, etc.
It seems to work for the few deckplans I've drawn up. YMMV.
PS. Yeah, I go for 1m corridors, too.