Secondary hull?

[Twin Agate Dragons]

It occurs to me that in Star Trek, no one ever thinks about the lives that are lost in a portion of the ship where the hull is fractured. So I'm curious (I'm still awaiting my package from Amazon/UPS for my core Traveller book) about how much it would cost to add a secondary hull to a ship to minimize the loss of crew members and passengers.

 

[rust]

I think in Mongoose Traveller self sealing hulls plus the hull armour are
the equivalents of a double hull, the design system does not really inclu-
de the option for another kind of secondary hull.

 

[captainjack23]

Dispersed type hull would seem to fit the bill, no ? Or is that only in HG ?

 

[Twin Agate Dragons]

I think in Mongoose Traveller self sealing hulls plus the hull armour are the equivalents of a double hull, the design system does not really include the option for another kind of secondary hull.

Let's say for the sake of arguement that a culture isn't adavnce enough to have those techs. In that case, they would have to add another layer of 'skin' to the ship to create a second hull. In that case, how much extra would it cost to do so?

 

[rust]

Let's say for the sake of arguement that a culture isn't adavnce enough to have those techs. In that case, they would have to add another layer of 'skin' to the ship to create a second hull. In that case, how much extra would it cost to do so?

I think you could either treat it as a layer of armour, for at least 5 % of
the volume of the hull and at least an additional 5 % of the price of the
hull (titanium, available at TL 7), or you could treat it as a real second
hull, doubling the price of the hull.
There may be other ways to do it, like the one mentioned by the captain,
but I have no idea how to do it.

 

[AndrewW]

Dispersed type hull would seem to fit the bill, no ? Or is that only in HG ?

Yup, dispersed hull is High Guard.

Isn't really a double hulled 'oil tanker' option. Though it may not be as necessary as you might think as the only section affected is going to be the breach to the next iris valve.

There is a modular hull option though that's not really the same thing either.

One could take the hull cost, size it down a little smaller then the outer hull and make that an inner hull. Could use the area inbetween the hulls for fuel if desired.

 

[BP]

I think in Mongoose Traveller self sealing hulls plus the hull armour are the equivalents of a double hull, the design system does not really include the option for another kind of secondary hull.

Let's say for the sake of arguement that a culture isn't adavnce enough to have those techs. In that case, they would have to add another layer of 'skin' to the ship to create a second hull. In that case, how much extra would it cost to do so?

That would seem highly strange - not being able to do such, yet have the tech to build a spaceship?...

I can see an advantage to the double hull, though, in terms of combat (hull can be destroyed 'twice'). This, of course, requires a rule tweak (though minor).

As for cost, just double the volume of the added armour (without the armour points) and charge the regular armour cost.

In combat - at least in CT (not sure if this is stated in MgT) - ships were assumed to self-decompress to avoid rapid decompression.

 

[AndrewW]

That would seem highly strange - not being able to do such, yet have the tech to build a spaceship?...

Well, self sealing does require TL 11+, can build spaceships at a lower TL.

In combat - at least in CT (not sure if this is stated in MgT) - ships were assumed to self-decompress to avoid rapid decompression.

Usual would be for the crew to be in vacc suits or equivelant with the ship depressurized.

 

[Beastttt]

the idea of the secondary hull in the Star trek universe is that the saucer section is a life boat
those that did not make it out would hopefully find a shelter closet to wait out in or get to a life pod in the secondary hull and use it to either make planet fall or link up with the saucer section at a later time

I would figure most ships would have internal bulkheads that would seal during red alerts
but if you are in a compartment that was penatrated you are SOL

there have been occasions of back up force field generators to plug breaches
but it is after a crew man or two has been sucked out

 

[phavoc]

In Star Trek there are force fields that are automatically erected when the hull is penetrated, or when the damamge goes far enough into the interior they erect forcefields around the area and within the corridors to retain the atmosphere.

For a traveller ship, of any size at least, you should be able to seal off affected sections and move around them while still retaining your atmosphere. I would think that larger warships, and maybe a few civilian ones, would have internal bulkheads that act as watertight bulkheads in today's ships.

 

[Captain Brann]

HI
I would use reinforced Hull for a second internal hull and reinforced structure for bulkheads. That and armored bulkheads for primary systems should be enough.

Chris

 

[Klaus Kipling]

HI
I would use reinforced Hull for a second internal hull and reinforced structure for bulkheads. That and armored bulkheads for primary systems should be enough.

Chris

Yup, seconded. The build rules work because they keep the specific technology vague enough to fit any ref preference. Hull and structure reinforcement would account for second hulls and better protected bulkheads.

 

[Infojunky]

High Guard has what is called the Vault which is essentially a inner armored core.

 

[alex_greene]

I believe that what is being referred to here is the concept that two or more parts of the ship's hull are designed to split apart in an emergency and manoeuvre more or less autonomously.

It's like having a 20000 dton ship.

Primary hull - 12000 dtons. Main J-drive, M-drive, fuel and powerplant. Main computer, flight deck and main sensor array. Main Engineering. Auxiliary bridge.

Secondary hull - 8000 dtons. Aux M-drive, aux power plant, aux fuel supply, main staterooms, sickbay, recreational facilities, secondary batteries, auxiliary sensor array, aux computer, main bridge.

When the ship is one single unit, all the ship's operations are shared by all facilities throughout the ship. As two separate units, the primary hull is overpowered (because the drive and power plant are designed for a much bigger ship) and that's the part of the ship that goes in fighting, while the secondary hull is meant to flee the immediate scene and take non-essential passengers and personnel off to safety.

Something like that.

You could carry it off with making the hull modular; provided that no more than 75% of the hull is modular, if you had an aux bridge, drives, power plant, fuel and computer, you could pull it off.

How does that sound?

 

[Deniable]

That's the way I read it too. In Traveller terms, the ship Alex describes sounds a bit like a Battle Rider/Tender combo. I'm not sure how to build one in MGT. It might be time to read MHG.

 

[BP]

I believe that what is being referred to here is the concept that two or more parts of the ship's hull are designed to split apart in an emergency and manoeuvre more or less autonomously...

Not quite as stated ('lives that are lost in a portion of the ship where the hull is fractured') and responded to by the original poster - though that is probably what he was originally trying to refer to.

High Guard does have the detachable bridge option, though it is limited by tonnage. It is almost backwards to ST in a way (not really armed, command crew only, soft landing ), but then Traveller starship design really doesn't accommodate families.

The 6,000 ton limit seems even more backwards (think - admiral fleeing his doomed command ship and leaving the grunts to fend for themselves).

I've used my own version of this in combination with reaction drives for fast escaping a doomed vessel (and other fun twists).

 

[alex_greene]

In your Traveller Universe, you can pretty much do whatever you wish.

Myself, I like designing ships with sculpted, graceful curves - particularly those not intended for atmospheric travel. Naval architects tend to be enamoured of symbols of graceful movement, usually flight - which explains the continued love of bilateral symmetry of ships that will never hit atmo, and which subsequently need never be designed to fly.

For instance, I usually design vessels not with a detachable bridge, but with a main bridge, an aux bridge buried deep in the guts of the ship near the centre of gravity, and a Captain's Gig parked just behind the bridge.

Also, non-atmo vessels don't have to have the bridge on top of the dorsal surface of the ship. It can be parked beneath the vessel like the gondola of an airship, especially if the spaceship is never intended to land on a surface.

 

[BP]

... aux bridge buried deep in the guts of the ship near the centre of gravity, and a Captain's Gig parked just behind the bridge.

Uh... because that was the only real space left to put the gig, right!

For combat ships it really makes sense to put important areas of the ship in unusual/well protected locations. Except crewing in smaller ships - even the J-Drive optimally should not be located next to the M-Drive. And camo/false sensor props/shielding/tech would be an obvious feature.

 

[alex_greene]

... aux bridge buried deep in the guts of the ship near the centre of gravity, and a Captain's Gig parked just behind the bridge.

Uh... because that was the only real space left to put the gig, right!

For combat ships it really makes sense to put important areas of the ship in unusual/well protected locations. Except crewing in smaller ships - even the J-Drive optimally should not be located next to the M-Drive. And camo/false sensor props/shielding/tech would be an obvious feature.

Main bridge.

Of course if the ship's in two halves and the aux bridge looks like it's about to take a hit, maybe a tiny auxiliary gig behind the aux bridge, buried deep in the framework of the vessel, that is exposed when the ship's in battle mode, might make sense.

Provided nobody tries to fire up her engines while she's still inside the ship ...

 

[Infojunky]

That's the way I read it too. In Traveller terms, the ship Alex describes sounds a bit like a Battle Rider/Tender combo. I'm not sure how to build one in MGT. It might be time to read MHG.

That is easy, you build two ships, one as the escape hull the other with all the fittings of the combined hull tonnage including clamps for escape hull....