Starship Hull design

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phavoc
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Starship Hull design

Postby phavoc » Thu Apr 27, 2017 10:12 pm

Does anyone else design ships that don't land in a different manner than those that are meant to land on the surface of a planet? I've always adopted the idea that ships who dock with stations would be long and narrow, with their primary cargo/passenger boarding in the nose of the ship. Why? Because on a spacestation there is a finite amount of space available for docking externally, especially when you consider you won't be docking on every nook and cranny. That means you'll have primary docking ring for ships docking externally, with the ability to create hangars pretty much everywhere, though even then from a safety factor you'd want to separate ship docking from habitable areas whenever possible.

Ships meant for atmosphere can be pretty much any configuration that is capable of landing on the ground. There are very few canon designs that reflect the nature of docking in space most of the time vs. landing on the ground.
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Re: Starship Hull design

Postby Condottiere » Thu Apr 27, 2017 10:19 pm

If the ship is equipped with an anti gravity field, you're probably looking at a VTOL belly landing dirtside.

Some starports and spacestations grow organically, so you could have a large range of docking arrangements.

New ones or renovated ones may rethink this, and re-arrange their system to one they consider most efficient for their purposes and configuration.
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Re: Starship Hull design

Postby h1ro » Fri Apr 28, 2017 6:02 am

I like ships with external cargo. I figure the ships don't dock, they "park" somewhere near by and small craft load containers into the external cargo racks. Passengers and crew use shuttles to travel between the port and ship. Refuelling and topping up supplies is done by tanker/supply ships, minor repairs can be carried out by repair drones.

Generally the ships are close structures and can't land.

I like the idea of ports at Lagrange points L4 and L5 in busier systems tho they can be a fair distance from the main world. From a security POV that could be a good thing, minimizing the number of ships pottering about in relatively close orbits to a main world with millions or billions of inhabitants seems wise if not very in keeping with Traveller's idea of "routine" space travel.
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Re: Starship Hull design

Postby phavoc » Fri Apr 28, 2017 1:42 pm

h1ro wrote:
Fri Apr 28, 2017 6:02 am
I like ships with external cargo. I figure the ships don't dock, they "park" somewhere near by and small craft load containers into the external cargo racks. Passengers and crew use shuttles to travel between the port and ship. Refuelling and topping up supplies is done by tanker/supply ships, minor repairs can be carried out by repair drones.

Generally the ships are close structures and can't land.

I like the idea of ports at Lagrange points L4 and L5 in busier systems tho they can be a fair distance from the main world. From a security POV that could be a good thing, minimizing the number of ships pottering about in relatively close orbits to a main world with millions or billions of inhabitants seems wise if not very in keeping with Traveller's idea of "routine" space travel.
Carrying cargo externally brings up a fair and very valid question - what is that container made of? We know that starship hulls are incredibly tough and expensive. After all they must be able to withstand micrometeroid hits while travelling at extremely high velocities. Containers, on the other hand, are (or should be) quite cheap - VERY cheap - by comparison. Why? Because ubiquity doesn't come unless something is relatively cheap and affordable. New 48' ocean-rated containers cost about $5,000, and can be had for as little as $2k used. That's Cr1,200 or so, depending on the dollar to Cr conversion rate you wanna use.

And these aren't vacuum-rated and radiation-shielded containers. So if you plan on getting your cargo to it's destination while it's still usable you need to expect to use starship-grade materials to build the hull. At least if you want to be fair about things. Traveller IS a game, so it's easy to toss out the reality and just hand-wave it away.
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Re: Starship Hull design

Postby h1ro » Fri Apr 28, 2017 2:22 pm

We've discussed containers a few times, but they've not really been documented in any "official" rules. From our previous discussions the parallel with current intermodal shipping seems to work with larger ships travelling longer distances to main ports and smaller ships distributing from there.

Designing the containers with HG using the modular thing works but yes, it is stupidly expensive compared to a current day container. The way I look at it is what's the alternative? How does a smaller ship with internal cargo compare in price? Alternatively a house rule for container construction could work but I haven't written one.

I don't know if anyone has designed a container ship that can carry 19,000 TEUs using the Vehicle Hand Book and compared the price with the actual price today. I guess it's kinda moot or at least, taking the comparison a little further than we really need to as it is indeed, a game.

ETA: To be clear, I've enjoyed the previous discussions and have used the info as pretty much a standard in my version of the 3I.
Last edited by h1ro on Fri Apr 28, 2017 2:44 pm, edited 1 time in total.
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Re: Starship Hull design

Postby h1ro » Fri Apr 28, 2017 2:29 pm

Oh and by the way, the new Jump Nets in High Guard have been universally dismissed in my group as silly... and I do think that the external cargo mounts should have some kind of tonnage as part of the ship. Tho maybe not, it could be that there's a gantry or structure of some sort that holds the containers but if we're making them out of starship hulls or similar then the important thing is how they join and as long as that's solid, I'd hand wave it and say it's good to go.
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Re: Starship Hull design

Postby h1ro » Fri Apr 28, 2017 2:34 pm

Another aside, it's always been Traveller's thing to make ships look more like aeroplanes that I think they ever would. I'm told, from an engineering POV ships are far more likely to be cylindrical and/or spherical but as we've got the mother of all hand waves - grav plates that mean you can stand in a ship as you would on a 12,000km planet, then we got to make cool deck plans that we could run around on and shoot people.
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Re: Starship Hull design

Postby phavoc » Fri Apr 28, 2017 4:39 pm

h1ro wrote:
Fri Apr 28, 2017 2:22 pm
We've discussed containers a few times, but they've not really been documented in any "official" rules. From our previous discussions the parallel with current intermodal shipping seems to work with larger ships travelling longer distances to main ports and smaller ships distributing from there.

Designing the containers with HG using the modular thing works but yes, it is stupidly expensive compared to a current day container. The way I look at it is what's the alternative? How does a smaller ship with internal cargo compare in price? Alternatively a house rule for container construction could work but I haven't written one.

I don't know if anyone has designed a container ship that can carry 19,000 TEUs using the Vehicle Hand Book and compared the price with the actual price today. I guess it's kinda moot or at least, taking the comparison a little further than we really need to as it is indeed, a game.

ETA: To be clear, I've enjoyed the previous discussions and have used the info as pretty much a standard in my version of the 3I.
I think in 1e there was a 100,000 freighter. Haven't seen anyone make a specific container-style ship.

I have no issue with bolting a container on the outside of a ship. Or using an external tank either. However I do feel it's cheating if those tanks/containers are NOT built to same standards as the external hull is. Sure, you can use them as long as you are willing to take the risk of a hull rupture or having your cargo irradiated or frozen, or all of the hazards that space offers you. Which would lead the discussion back to cheap containers being carried INSIDE a starship / spaceship. Or at a maximum the containers might be more robust than a normal container, but it's exposed to space for hours only, just long enough to pull out of a ship and put in another one, or to be taken down stacked and secured externally on a cargo lighter or something of the sort.
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Re: Starship Hull design

Postby Reynard » Fri Apr 28, 2017 6:27 pm

I believe the big disadvantage to externally mounted fuel, small craft and cargo is they are subject to hull hits and automatically considered destroyed as they are not protected by the ship's armor or hull. They sound great until something attacks the ship.
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Re: Starship Hull design

Postby Condottiere » Fri Apr 28, 2017 6:50 pm

We don't know how thick a spaceship hull is, anyway.

So just armourplate the container's corrugated steel skin with factor one; interestingly, armourplating cost is a percentage based on the hull default cost.
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Re: Starship Hull design

Postby AnotherDilbert » Fri Apr 28, 2017 8:28 pm

If it's the same as in MT armour is about 10 cm to 100 cm.
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Re: Starship Hull design

Postby Reynard » Sat Apr 29, 2017 12:38 am

Hmm, now those cheap cargo and fuel units are getting expensive. Thing is you only have YOUR cargo or fuel pod protected. All right I guess if you never have to lose or exchange them.
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Re: Starship Hull design

Postby h1ro » Sat Apr 29, 2017 4:00 am

Coming back to the cost of a container, it seems reasonable to use the same cost as a drop tank: Cr25,000 per dT. A 40' container is roughly 5dT or Cr125,000 for it's space equivalent. That's half the price of the equivalent ship hull and way more than the 21st century container. Should it have a power requirement? Maybe but as vacuum insulates well it shouldn't take too much energy to maintain a temperature suitable for it's contents.
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Re: Starship Hull design

Postby AnotherDilbert » Sat Apr 29, 2017 1:59 pm

A 40' container has a surface of about 12 m × 2.5 m × 4 + 2.5 m × 2.5 × 2 ≈ 130 m².
Radiated energy is about σT⁴ per square metre, so 5.67 × 10⁻⁸ × (290 K)⁴ × 130 m² ≈ 52 kW or about 0.005 Power.
So, yes it needs power, but in negligible (for a starship) amounts.
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Re: Starship Hull design

Postby phavoc » Sat Apr 29, 2017 6:36 pm

h1ro wrote:
Sat Apr 29, 2017 4:00 am
Coming back to the cost of a container, it seems reasonable to use the same cost as a drop tank: Cr25,000 per dT. A 40' container is roughly 5dT or Cr125,000 for it's space equivalent. That's half the price of the equivalent ship hull and way more than the 21st century container. Should it have a power requirement? Maybe but as vacuum insulates well it shouldn't take too much energy to maintain a temperature suitable for it's contents.
That would make empty containers a gold miNE to steal. :)

It certainly does pUT the idea into a different perspective. There wouldn't me much energy requirements, though that would depend on if you needed temperature and gravity, and while it's negligible for a starship, more than a handful of containers might really start adding up.

And that brings up another poit. Without gravity the cargo is fully exposed to g forces. Anything not fully strapped down will float up and potentially be damaged with acceleration or vector changes.
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Re: Starship Hull design

Postby h1ro » Sat Apr 29, 2017 7:05 pm

I know a guy can get you work doing security for the empty container parking lot. Ya get a nice uniform and all...

Valid points on pulling G towing containers. Solution could be a few points. Firstly, price them as ship hulls and include grav plates and a power requirement. Secondly, restrict cargo ships to non violent manoeuvres which makes sense anyway. Lastly, buy a bunch of ratcheting straps and weld a bunch of tie points inside the containers ;)
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Re: Starship Hull design

Postby Condottiere » Sat Apr 29, 2017 9:41 pm

Steel is cheap, and we'll assume most goods don't need air.

My assumption is that most containers meant for external stowage are more larger and robust, and designed to keep their contents safe from an external environment, than our standard forty foot one.
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Re: Starship Hull design

Postby h1ro » Sun Apr 30, 2017 3:14 pm

Doesn't mean they'll do well under acceleration or at very low temperatures. Just as today tho, there can be different grades of container, made to tolerate different G, atmospheric conditions etc. Doesn't need to be hugely complicated but yes, it adds cost to space travel which may unbalance the trade rules, depends how you play your game.
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Re: Starship Hull design

Postby phavoc » Sun Apr 30, 2017 5:31 pm

Condottiere wrote:
Sat Apr 29, 2017 9:41 pm
Steel is cheap, and we'll assume most goods don't need air.

My assumption is that most containers meant for external stowage are more larger and robust, and designed to keep their contents safe from an external environment, than our standard forty foot one.
Ocean going containers ARE pretty tough. They get constant exposure to salt air, waves, rain, sun, etc. But they also don't traverse the arctic areas and they get some break from the sun with clouds and nightfall. Space will suck the heat out of standard container pretty fast, leaving the contents exposed to atmosphere and far below zero temperatures. Most consumer goods aren't meant for that sort of extreme, and even some raw materials would be damaged as well. Plus if you are near enough to a sun those containers will heat UP when exposed to high temperatures from the sun, and then flash freeze when going into shadow. Needless to say externally cargo needs to be something that can take extreme temps and radiation without any harm. Which mostly leaves you with raw materials like ores and such. Anything else would need the protection of a real hull and at least a semblance of atmospheric control. Gravity can be offset with better packing and tie-downs. Ships with externally carried cargo's should be limited in their maneuvers.

We often use aircraft with external tanks as examples. But with a few exceptions (like the FAST tanks on a F-15 which are essentially bolted-on hull), aircraft with external tanks are quite limited in their actions as far as maneuvers go. To take full advantage of their maneuverability they have to jettison those tanks - the attachment points are sufficiently strong to hold them but not for violent maneuvers that fighters are required to do in combat. Cargo containers would potentially fall under the same concept. That docking clamp is meant to hold fast a cargo under normal conditions. But making radical evasions, especially at higher G, would put a strain on them that far exceeds normal operations.
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Re: Starship Hull design

Postby Condottiere » Sun Apr 30, 2017 10:31 pm

And speaking of technically consistent, how are spaceships in the sixth millenium insulated?

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