Question about Streamlined warships

[McPerth]

Concur, taking time will help, but to get the same roll as a streamlined ship, you'd need to extend the 10-60 minute landing evolution to 6-24 hours. Though I guess it makes sense for something huge and ungainly like a Tigress to take that long to land carefully. That actually does work for me.

Well, not necesarly too long…

As you say, you need a 8+. A decent pilot (Stat DM+1, skill 2) makes it a 5+. Add some expert software in your computer to help him and he may have a +1 more. Taking 1-6 hours instead of 10-60 minutes gives you a further +1, so you need a 3+. On Eyes you have a level 1 failure, IMHO a rough landing that may discomfort the crew/passengers or break something, but it’s not a serious one…

And of course, a better pilot even avoids this (but don't try it with a worse one)...

Alas, the Tigress has no subcraft with cargo capacity, and with a fuel requirement of 190,000 tons, that's going to be super hard to arrange. To take the time to refuel with the same roll as a streamlined ship, it would move the base time up to 10-60 hours.

But I guess a Tigris seldom goes alone. Let’s imagine it is escorted by 6 10 kDt Destroyers, each with at least 4000 dtons of fuel (as they must be J4 to accompany the Tigris). That’s 24000 dtons of fuel per fuel run, so in about 8 such runs to fully fuel the Tigris (and another to refuel themselvves after it). And they are likely to have more auxiliary ships accompaining it...

As according most sources, a fuel run takes about 8 hours, that makes it 3-4 days, let’s say a week to fit within the FFW rules as a unstreamlined counter…

Making the run itself seems me quite suicidal, as I cannot imagine such a behemoth entering in atmosphere (despite having fuel scoops, that I’d never added to it and see more to comet refueling). YMMV, of course

Having the purification plant, though, makes more sense, as so it doesn’t force the refueling ships to purify it themselves, and allows them to concentrate in fuel runs, while the Tigris itself (and its fighters) keep the High Guard in orbit of the Gas Giant.

 

[mike wightman]

Mass is irrelevant - the consensus is that 14 cubic metres could be filled with lead and the ship is not affected.

 

[kilemall]

Mass is irrelevant - the consensus is that 14 cubic metres could be filled with lead and the ship is not affected.

That’s later ones, I rather like treating starships as more aircraft then train, having lighten or balance the load be an issue.

 

[Badenov]

Well, not necesarly too long…

As you say, you need a 8+. A decent pilot (Stat DM+1, skill 2) makes it a 5+. Add some expert software in your computer to help him and he may have a +1 more. Taking 1-6 hours instead of 10-60 minutes gives you a further +1, so you need a 3+. On Eyes you have a level 1 failure, IMHO a rough landing that may discomfort the crew/passengers or break something, but it’s not a serious one…

And of course, a better pilot even avoids this (but don't try it with a worse one)...

That's a bit more bonus to roll than I typically expect. You need a 9 or better in a stat to get a +1, which is pretty uncommon, where as Pilot 2 in't too tough, particularly in a helmsman on a 500,000T ship during a special evolution. I hadn't considered the Expert program. 1-6 hours isn't awful, but if 1 in 36 landings causes damage, that's going to add up over the lifetime of a ship. It might not add up to too much, though, and just get rolled up into operating costs.

But I guess a Tigris seldom goes alone. Let’s imagine it is escorted by 6 10 kDt Destroyers, each with at least 4000 dtons of fuel (as they must be J4 to accompany the Tigris). That’s 24000 dtons of fuel per fuel run, so in about 8 such runs to fully fuel the Tigris (and another to refuel themselvves after it). And they are likely to have more auxiliary ships accompaining it...

As according most sources, a fuel run takes about 8 hours, that makes it 3-4 days, let’s say a week to fit within the FFW rules as a unstreamlined counter…

Making the run itself seems me quite suicidal, as I cannot imagine such a behemoth entering in atmosphere (despite having fuel scoops, that I’d never added to it and see more to comet refueling). YMMV, of course

Having the purification plant, though, makes more sense, as so it doesn’t force the refueling ships to purify it themselves, and allows them to concentrate in fuel runs, while the Tigris itself (and its fighters) keep the High Guard in orbit of the Gas Giant.

A fuel scooping evolution is 1-6 hours, assuming you make the roll on the first try. If it takes you two tries, you're scooping 2d6 hours, and on the rare 2nd faiilure, that'd add another d6. I can see that averaging out to 8 hours. That actually seems reasonable.

Mass is irrelevant - the consensus is that 14 cubic metres could be filled with lead and the ship is not affected.

Is there a reference for this? I've never seen this anyplace before, and it doesn't make sense that a ship's cargo is rated in tons if weight doesn't matter.

 

[McPerth]

That's a bit more bonus to roll than I typically expect. You need a 9 or better in a stat to get a +1, which is pretty uncommon,

It's not as uncommon. From metagaming POV, rolling 9+ is 10/36 chance, so about 27%. Add to this training and you'll find it not so uncommon as not to assume most pilots in unstreamlined ships might have it, if it's seen as a good asset to pilot them.

Neither is so rare to have a skill at 3+, that would be the same...

Is there a reference for this? I've never seen this anyplace before, and it doesn't make sense that a ship's cargo is rated in tons if weight doesn't matter.

Is implicit in the very concept of ship design in CT MgT (not in MT, TNE and, IIRC, T4, where mass was also taken into account, though only reaction mass drives were affected by it, gravitic ones being not), as the dton is described as a volume measure, not as a mass one. See that the cargo cold (or fuel tanks) being empty or full does not affect ship's perfomance.

My excuse to handwave it (I claim it not to be anything more) is that, as drives are gravitic and use gravitic force, adding mass also adds gravitic force, so overcoming the effects of this increased mass

 

[kilemall]

It's not as uncommon. From metagaming POV, rolling 9+ is 10/36 chance, so about 27%. Add to this training and you'll find it not so uncommon as not to assume most pilots in unstreamlined ships might have it, if it's seen as a good asset to pilot them.

Neither is so rare to have a sill at 3+, taht would be the same...



Is implicit in the very concept of ship design in CT MgT (not in MT, TNE and, IIRC, T4, where mass was also taken into account, though only reaction mass drives were affected by it, gravitic ones being not), as the dton is described as a volume measure, not as a mass one. See that the cargo cold (or fuel tanks) being empty or full does not affect ship's perfomance.

My excuse to handwave it (I claim it not to be anything more) is that, as drives are gravitic and use gravitic force, adding mass also adds gravitic forece, so overcoming the effects of this increased mass

To be clear they originally did talk cargo as being 1000kg per ton and didn’t make the hydrogen volume connection explicit until later. It probably was intended all along.

Badenov, the term we usually use to cover the volume concept is dton or displacement ton. This is a pretty good article sussing out what dtons work out to with real world objects.

Freelance Traveller - The Shipyard - What is Tonnage?

 

[chipla]

Which is a 'You make the call.' What I was hoping for was official guidance. Me making the call almost always ends up being not a good call.

One of the Mongoose JTAS pdfs for 2e has a whole section on landing if you want something official for their editions. IIRC it runs from buttery smooth landing that the passengers don’t feel to slight bump as you touch down to landing gear collapses to crash.

 

[TamsinP]

To be clear they originally did talk cargo as being 1000kg per ton and didn’t make the hydrogen volume connection explicit until later. It probably was intended all along.

Badenov, the term we usually use to cover the volume concept is dton or displacement ton. This is a pretty good article sussing out what dtons work out to with real world objects.

Freelance Traveller - The Shipyard - What is Tonnage?

Just as a note on that article, the sections "Gross Tonnage" and "Net Tonnage" are actually referring to Gross and Net Register Tonnage, which is no longer used.

Gross Tonnage (GT) and Net Tonnage (NT) are the current schemes and are not a direct measure of volume (their Wikipedia entries give the formulae used to calculate them). IMHO, NT is one of the most useless measures anybody could have come up with as (for cargo capacity; there is an additional component for passengers) in addition to the same base formula used to calculate GT, it is then modified by a ratio of depth and draft - that means that two ships with identical cargo hold volumes but different drafts/depths can have different NT values. Trying to calculate volume from GT is very difficult; fortunately there is this online calculator (and possibly others) you can use: https://www.convert-me.com/en/convert/volume/tonnage/tonnage-to-m3.html?u=tonnage&v=24


GRT/NRT and GT/NT also measure slightly different volumes. GRT/NRT measure the permanently enclosed volume, which excludes semi-open decks (eg promenade and boat decks on passenger ships) whereas GT/NT measures the moulded volume which does include semi-open decks.

 

[Jame]

The question is: What is cheaper, a non-streamlined warship with a tanker, or a streamlined warship?
Answer: Warships are streamlined, in order to be strategically mobile.
There are enough systems without gas giants to be a problem. If there are neither gas giants nor oceans, you need tankers or drop tanks.



Simplified:

So, a Tigress would need an escort or tanker with a total of ~96 kDt fuel capacity to refuel quickly (less than a day?) at an ocean, or ~20 kDt to refuel slowly (approaching a week?).


If a fleet has enough streamlined ships, refuelling is quick and easy.
If a fleet has some streamlined ships, refuelling is slow and cumbersome.
If a fleet has next to no streamlined ships, refuelling is an adveadventure.

This is my take on it; most warships would be at least partially streamlined in order to accommodate this.

 

[Badenov]

One of the Mongoose JTAS pdfs for 2e has a whole section on landing if you want something official for their editions. IIRC it runs from buttery smooth landing that the passengers don’t feel to slight bump as you touch down to landing gear collapses to crash.

That sounds promising, I will try to track it down.

 

[TamsinP]

That sounds promising, I will try to track it down.

It's Mongoose JTAS #03, the article is "Jump Point to Port" which may be a reprint or update of the similarly titled article from the original GDW JTAS issues.

 

[warwizard]

TNE and T4 FF&S have entries for fuel purifiers, you can install the full sized ones for the RAW times, or install smaller ones that can do the job while you are in jump, leading to the carrying the 2nd jump worth of fuel at a rate of 1.56 dt of jump fuel per dt, putting the newly refined fuel into the now empty jump fuel tanks. What to do with the 12,440kg of O2 for every ton of LH2 you purified? Even a 100 Dt J-1 ship will generate 124,400kg of O2 during this process. The jump bubble is H2 filled per RAW, I hesitate to put O2 overboard into an environment of gassious H2. Perhaps dedicate an extra 2 tonnes of cargo as a large high pressure oxygen tank. Not recommended for ships that might be getting shot at. Perhaps better is to jump first then refine your fuel while doing your standard week of interaction with the starport.

 

[mike wightman]

There is no hydrogen filled jump bubble in TNE, it was introduced in T4, and it contradicts the existence of collector and antimatter powered jump drives.

 

[Grav_Moped]

You wouldn't even need 14,000kg of water, just 9,000kg of water would be 1000kg of hydrogen, but even that would put a strain on Thrust 1 ships trying to carry it as water or ice while converting it, the ship would be +8 tons per ton of fuel to carry it that way.

For rules systems that specifically deal with starship mass, yes.

Those that don't, really should have the referee house-rule about this if it comes up.

 

[Grav_Moped]

That wouldn't work. Fuel tankage can't be used for cargo and cargo holds can't be used a fuel tanks. You would need two 30-ton modules, one for cargo and one for fuel.

This is what High Guard introduced collapsible tanks for... can't be directly used for jump fuel, but if it was going to be cargo anyhow...

 

[TamsinP]

This is what High Guard introduced collapsible tanks for... can't be directly used for jump fuel, but if it was going to be cargo anyhow...

Funnily enough, I was having a discussion about this on Reddit the other day, pointing out the pros & cons of (de)mountable tanks, collapsible tanks and fuel/cargo tanks. For a J2 (or even J3, though that is unlikely) freighter operating on a J1 main some of the time, the fuel/cargo tank is probably the best option; collapsible tanks are only suitable for low-jump freighters which occasionally need to cross a 2-parsec gap; (de)mountable tanks would mostly be used by larger lines where they have standardised ships capable of a high jump but where the routes operated vary in length and commit individual ships to particular routes long term, fitting the extra tanks for the longer routes as needed - some of the Tukera Lines ships on the Wiki are examples of this (J4 drives but only 1-parsec of permanent fuel tanks).

 

[Grav_Moped]

Funnily enough, I was having a discussion about this on Reddit the other day, pointing out the pros & cons of (de)mountable tanks, collapsible tanks and fuel/cargo tanks. For a J2 (or even J3, though that is unlikely) freighter operating on a J1 main some of the time, the fuel/cargo tank is probably the best option; collapsible tanks are only suitable for low-jump freighters which occasionally need to cross a 2-parsec gap; (de)mountable tanks would mostly be used by larger lines where they have standardised ships capable of a high jump but where the routes operated vary in length and commit individual ships to particular routes long term, fitting the extra tanks for the longer routes as needed - some of the Tukera Lines ships on the Wiki are examples of this (J4 drives but only 1-parsec of permanent fuel tanks).

And then you get @Spinward Flow using collapsible tanks combined with shifting cargo modules from interior cargo to external carriage to achieve variable-tonnage ships that the rules don't otherwise provide for.

 

[Spinward Flow]

And then you get @Spinward Flow using collapsible tanks combined with shifting cargo modules from interior cargo to external carriage to achieve variable-tonnage ships that the rules don't otherwise provide for.

If you build a better mousetrap paradigm ...

 

[Carlobrand]

CT Book 2 you have to buy streamlining at the outset or you can't. CT book 5 some designs are streamlined (they can land), some are partially streamlined and can scoop but not land, some are unstreamlined and can do neither. Except Broadsword, who could "ground". MT you have to be streamlined unless you're below a certain size, in which case you can be a slow flying brick.

For all practical purposes, streamlining only affects your flight characteristics. Flight characteristics are less relevant if you're using thrust to stay up instead of aerodynamics. You can literally attach rocket packs to a brick and make yourself a flying brick, the only issue there being how to control the thing: gotta keep that center of gravity in the right place or the thing inverts and flies straight down.

Assuming you're not trying to do it in a storm, the only things that should stop you from "grounding" any craft are the design of the craft itself - real easy to see a dispersed structure start falling apart as it tries to back down on its drives - and the ability of the craft to support itself once it's down. Characteristics of the world itself make a difference: low-G low atmosphere worlds are certainly easier than high-G high atmosphere worlds. If the craft isn't designed with landing struts, you may find it's like that old adage about stopping a bullet: you can do it - once. You're just not getting back up again, which still may be the better thing if the alternative is to see your passengers and crew die. Then there's the ground pressure problem: you land, the ground gives unevenly, you fall over sideways. A water landing helps but there may be some awkward complications involved, like your cooling system violently objecting to radiating into water instead of into vacuum, or your craft ending up sideways instead of upright and leaving you wondering how you're going to manage a take-off, or discovering that your craft is denser than water and you're not equipped to exit underwater. Broadsword was a bad design for flying but a good design for grounding. If you're not streamlined and you're not a Broadsword, plan-B is probably to pick a well-equipped starport that has a cradle able to accept your craft and a "harbor pilot" with lots of training in grounding craft.

 

[Badenov]

CT Book 2 you have to buy streamlining at the outset or you can't. CT book 5 some designs are streamlined (they can land), some are partially streamlined and can scoop but not land, some are unstreamlined and can do neither. Except Broadsword, who could "ground". MT you have to be streamlined unless you're below a certain size, in which case you can be a slow flying brick.

For all practical purposes, streamlining only affects your flight characteristics. Flight characteristics are less relevant if you're using thrust to stay up instead of aerodynamics. You can literally attach rocket packs to a brick and make yourself a flying brick, the only issue there being how to control the thing: gotta keep that center of gravity in the right place or the thing inverts and flies straight down.

Assuming you're not trying to do it in a storm, the only things that should stop you from "grounding" any craft are the design of the craft itself - real easy to see a dispersed structure start falling apart as it tries to back down on its drives - and the ability of the craft to support itself once it's down. Characteristics of the world itself make a difference: low-G low atmosphere worlds are certainly easier than high-G high atmosphere worlds. If the craft isn't designed with landing struts, you may find it's like that old adage about stopping a bullet: you can do it - once. You're just not getting back up again, which still may be the better thing if the alternative is to see your passengers and crew die. Then there's the ground pressure problem: you land, the ground gives unevenly, you fall over sideways. A water landing helps but there may be some awkward complications involved, like your cooling system violently objecting to radiating into water instead of into vacuum, or your craft ending up sideways instead of upright and leaving you wondering how you're going to manage a take-off, or discovering that your craft is denser than water and you're not equipped to exit underwater. Broadsword was a bad design for flying but a good design for grounding. If you're not streamlined and you're not a Broadsword, plan-B is probably to pick a well-equipped starport that has a cradle able to accept your craft and a "harbor pilot" with lots of training in grounding craft.

I think this comes under the heading of taking additional time to boost your roll or else taking more risk in your landing. You can let yourself down on pure grav thrusters more or less gently depending on local winds, and going down slowly takes more time than an aerodynamic descent, but boosts your roll, possibly back up to what you would roll for a streamlined craft. That's pretty reasonable, and the rules seem to support it.

The place where the rules are absent is at what stages of landing do you need to roll, and it could be just at the end because anything else you could recover from, and what happens if you do manage to fail your landing roll.

I'm not sure how 'grounding' is different from landing. Do non-streamlined or distributed ships not have landing gear at all like they don't come with fuel scoops (in Mongoose, at least)?