Astrogation question

[bsg1970]

I started our first Traveller game here in Chicago, have two players, (Hoping to add more) and basically we were a bit confused on ship astrogation and plotting checks, and mis-jumping. I also noticed that the Far Trader A that the characters started with, has a jump range of 1 parsec, which is not very far range at all...and we were confused about fueling, lets say the ship is hauling 3 tons of supplies for a contract, can they just scoop up enough fuel to fill the remainder of the cargo hold so they can make more jumps? where does this fuel go? into special ship containers? The pocket and main book seemed a bit lacking for information on this, especially if you fail your pre-jump calculations, and so on. Also, it seems that the characters start off woefully ill equipped, am I wrong in my assessment on this?

Thanks

brandon
Chicago
Black Sun Games

 

[alex_greene]

You can't directly fill your ship's cargo hold with fuel. You can, however, take a collapsible fuel tank and install that in the cargo hold. Sadly, I haven't a clue where this is referenced in the current series.

Basically, these tanks can collapse when empty to about 10% of their fully loaded volume. If you had, say, a 60-ton collapsible tank, it would reduce to 6 tons when collapsed. If you had a J-1 drive and J-3 worth of fuel, the tanks would lose the equivalent of one J-1 of fuel per Jump.

I can't tell you where this has appeared in the Mongoose books, nor any costs associated with these types of tanks. I can only say that it's probably the only way a J-1 Type A Free Trader can escape from a J-1 cluster separated by a couple of parsecs of empty hexes in all directions on the map.

 

[rust]

Welcome to the forum.

... lets say the ship is hauling 3 tons of supplies for a contract, can they just scoop up enough fuel to fill the remainder of the cargo hold so they can make more jumps?

If you use the core rules, the answer is "No". Filling your ship's cargo hold
with hydrogen without the special equipment required to handle that hy-
drogen would turn your ship into a bomb.
There are things like collapsible fuel tanks, fuel bladders and thelike that
allow to use the cargo hold as additional fuel tankage, but they are des-
cribed in the supplements, not the core rules.

Also, it seems that the characters start off woefully ill equipped, am I wrong in my assessment on this?

This depends on what you expect the characters to do. Their equipment,
including the stuff they can buy with their mustering out benefits, is usu-
ally quite sufficient for normal adventuring, but it does of course not en-
able them to conquer the galaxy. :wink:

 

[bsg1970]

Now, how exactly do you do astrogation? we spent a bit of time trying to figure this out, the books spell it out clearly, however when you lets say have a mishap on plotting, or a mishap when jumping, what exactly happens?

 

[rust]

Sadly, I haven't a clue where this is referenced in the current series.

Fuel bladders are in Spinward Marches, but I also do not remember where
collapsible tanks are described - or if they have been described already in
the Mongoose Traveller version at all.

 

[bsg1970]

I lived in Augsburg when I was stationed there in the Army! I think they tore down Sheridan kaserne.

 

[rust]

Now, how exactly do you do astrogation?

The astrogator makes his astrogation roll, and if he does not succeed, he
has lost the time and has to make another attempt. There are no other
consequences, the astrogator just has to repeat the procedure until he fi-
nally gets it right.

A misjump, usually caused by lack of maintenance or use of unrefined fu-
el, is very rare. If it does happen, the ship is normally destroyed - time
for new characters. A generous referee, however, can decide that the ship
reappears anywhere in space or time, in any condition he likes.

 

[rust]

I lived in Augsburg when I was stationed there in the Army! I think they tore down Sheridan kaserne.

They are still in the process of tearing it down and replacing it with civi-
lian housing. :wink:

 

[bsg1970]

I also lived in Flak, this might sound odd, but that place was haunted. I miss cafe Max, and the inbase, but I heard the inbase long closed down.

 

[rust]

I also lived in Flak, this might sound odd, but that place was haunted. I miss cafe Max, and the inbase, but I heard the inbase long closed down.

Cafe Max is still there, but otherwise a lot has changed in Augsburg over
the recent years. However, most of the former barracks are still standing,
Reese has now become a kind of cultural center with low rents for small
new enterprises. As for Flak, I have no idea what happened there, this is
a part of town I rarely visit.

 

[Blix]

Now, how exactly do you do astrogation? we spent a bit of time trying to figure this out, the books spell it out clearly, however when you lets say have a mishap on plotting, or a mishap when jumping, what exactly happens?

How it should work IMO is that you enter a star that you want to go to into your ship's computer system (which knows where you are currently), and it does all the calculating of the right vectors and times etc for you. Humans should not be calculating anything at all.

I have no idea why people are involved in "astrogation" at all; is the skill roll just to see if you typed the star name correctly?

 

[rust]

I have no idea why people are involved in "astrogation" at all; is the skill roll just to see if you typed the star name correctly?

I suspect it is an authorization procedure, convincing the computer that
the crew has paid its mortgage and is not attempting to take the ship to
any red zone or other area where the bank's property would be without
insurance, and all that ... :wink:

 

[bsg1970]

We were talking about that also, I am kinda doing a fire fly styled game, no Imperium, a kinda loose un-defined alliance, no aliens, psions are very rare. in the the first adventure the characters wanted a job, so they went to a bar in a star port looking for work, they of course asked the bar maid, who sent em over to a unsaviory fellow, well they wanted to haul goods, but they had no collateral, so the contact gave them a small 3 ton hauling job to a more remote planet. The players didn't ask what they were hauling, The goods were arms and equipment for a provincial government locked in a civil war. Think Liberia. Jungle planet, the ships captain had took a 50.000 credit payment to have the ships medic who has a good medic score 4, treat the President who needed surgery for a bad appendix. The players were really afraid that their ship would be attacked on the ground and they would be stranded on a war torn world filled with disease and cannibalism. They turned down a million credits to sneak into General "Killeveryone"s main camp to retrieve an apc the Warlord had, but didn't know how to use. The planet was TL 4 with some TL5-TLC6 equipment.

 

[AndrewW]

We were talking about that also, I am kinda doing a fire fly styled game, no Imperium, a kinda loose un-defined alliance, no aliens, psions are very rare. in the the first adventure the characters wanted a job, so they went to a bar in a star port looking for work, they of course asked the bar maid, who sent em over to a unsaviory fellow, well they wanted to haul goods, but they had no collateral, so the contact gave them a small 3 ton hauling job to a more remote planet. The players didn't ask what they were hauling, The goods were arms and equipment for a provincial government locked in a civil war. Think Liberia. Jungle planet, the ships captain had took a 50.000 credit payment to have the ships medic who has a good medic score 4, treat the President who needed surgery for a bad appendix. The players were really afraid that their ship would be attacked on the ground and they would be stranded on a war torn world filled with disease and cannibalism. They turned down a million credits to sneak into General "Killeveryone"s main camp to retrieve an apc the Warlord had, but didn't know how to use. The planet was TL 4 with some TL5-TLC6 equipment.

Next someone will be hiring them to board a train and liberate some medical cargo...

 

[bsg1970]

When I make adventures, I like to always make risk=reward, and give the players a chance to come up with ideas and I just follow through with them.

 

[rinku]

I was always a little dubious about the "fuel bladder" concept. This is liquid hydrogen, not kerosene or water.

Having said that, it should be possible for any ship to put normal commercial liquid hydrogen storage tanks in as cargo and transfer the fuel to normal ship tankage after jump, without any real problem. Based on the cost of drop tanks from High Guard and halving it, perhaps Cr1000 per ton?

 

[DFW]

I was always a little dubious about the "fuel bladder" concept. This is liquid hydrogen, not kerosene or water.

Actually, since it is for a second J1 you could fill it with H2O or ammonia. When you come out of your 1st jump you purify it into the main tanks as hydrogen and then jump again...

 

[alex_greene]

Now, how exactly do you do astrogation? we spent a bit of time trying to figure this out, the books spell it out clearly, however when you lets say have a mishap on plotting, or a mishap when jumping, what exactly happens?

How it should work IMO is that you enter a star that you want to go to into your ship's computer system (which knows where you are currently), and it does all the calculating of the right vectors and times etc for you. Humans should not be calculating anything at all.

I have no idea why people are involved in "astrogation" at all; is the skill roll just to see if you typed the star name correctly?

What, you can't believe that a human being can plot a course and lay in a plan in his head? Shame on you. Humans can spot a planet orbiting a distant star from the tiniest flicker in a planet's brightness. Humans can also outthink any computer - even in the Far Future, a computer with an AI can have its judgments overruled by any human.

 

[locarno24]

you enter a star that you want to go to into your ship's computer system

You enter a planet that you want to go to. Which is moving in orbit, so you need to figure out in which direction it will be going when you emerge and match your velocity.

which knows where you are currently

Depends how accurately.


I would be confident that civilian crewman 2nd class Jeff from some TL10 backwater that thinks the jump drive is all that is not going to do better than a jump control specialised computer. The astrogation checks are just making sure that you've put in the destination and velocity right to allow an easy transfer into orbit, and the jump computer going "that doesn't make sense, Jeff" repeatedly until he gets it right. It's probably not a lot more complex than drawing lines through a diagram in powerpoint, much like a commercial airliner today, whose pilots' principally roles are to make the passengers feel better and press the 'on' switch on the autopilot.

A TL15 special forces raider jump officer would be dealing with stuff you can't really automate - particle density from the solar wind affecting the fuel bubble, gravity wells associated with other ships in a squadron or bodies well outside their 100D limit, etc, etc. and will expect to jump in with ridiculous precision, such that the first missile is leaving the launch rail by the time the system's traffic control person gets halfway through yelling "What the [insert colloquial swearword of chouce] is That thing?"

A computer can handle that stuff but needs to be told how, just as with cutting edge tech today.

 

[Captain Jonah]

For the OP. Fittings and engineer rules are mine, other details are Traveller dating from clasic.

Have Starship, will Traveller 7
Longer Legs.

Merchant ships focus on cargo not jump range, many merchants are restricted to a single parsec or two of range. On the Imperium’s mains this is not a problem but what happens when you heed to go somewhere beyond the range of your Jump drive. More fuel is needed to allow a second or even third jump between refuelling. There are two main ways of doing this, both involve sacrificing cargo space for more fuel. The two main types of Cargo Fuel are:

Collapsible tanks

Collapsible tanks are purpose built for a ship and fuel capacity, they consist of a frame of structural braces and flexible bladders. The framework is locked into place in the cargo hold and the bladders can then be filled as needed. Collapsible tanks can be part assembled if required and can hold fuel up to the volume put in place. Such tanks can be taken down and stored as cargo when not needed but while assembled the framework prevents the volume being used for cargo even if the bladders are empty.

Extending or storing collapsible tanks require 6 man hours per 10 tons (roll 8+ engineer jump/power) each success reduces time by 30 minutes to min 3 hours per 10 tons, failures add 30 minutes each to max 9 hours per 10 tons. Collapsed tanks when folded down and stored take 1 ton of space per 20 tons of capacity or part thereof.

Fuel stored in collapsible tanks cannot be used directly to fuel a jump drive or power plant, it must be pumped into the main tanks first. Fuel can be transferred from the internal storage to the main tank at the rate of 50 tons per day unless the ship has additional fuel handling (see below).
Collapsible tanks are not strong. Any combat hit on a cargo hold will automatically rupture the bladders causing a fuel hit equal to the volume of fuel carried in addition to the cargo hit. Due to the problems with storage of Hydrogen in the bladders such fuel can be held for no more than four weeks before it begins to leak in to the cargo hold.

Internal demountable tanks

Internal demountable tanks are a series of pre assembled linked tanks in 1,5,10, 20 and 50 ton capacities which are loaded as cargo and anchored in the ship’s cargo bay. Internal demountable tanks must be removed from the ship to free up the cargo space as empty or full they take up their full volume. These tanks are loaded or unloaded at the same speed as normal cargo. They are purpose built to contain super cool liquids and gases and are robust enough to survive nearby shocks; they are only damaged on a normal fuel hit not on cargo hits.

Internal demountable tanks are directly connected to the ships main fuel tanks when set up. This takes the same time as it takes to set up a collapsible tank but in this case the time is spent setting up the internal fuel pipes and pumps that connect the tanks into the ship.
Fuel in Internal demountable tanks does not need to be transferred to the ship’s main fuel tanks, it can be used directly for jumps or the power plant.

Fuel Handling

Fuel stored in collapsible tanks cannot be used directly, it must be pumped into the main tanks first.
Ships who intend to make frequent use of Collapsible tanks can add fuel handling and pumping fittings to a cargo hold. Each ton of fuel handling allows an additional 50 tons of fuel per day to be moved from cargo into the main fuel tank and costs kcr10.

Without such extra fuel handling fuel is transferred at 50 tons per day. As this involves super cooled liquid H being pumped through flexible pipes laid across the ship’s decks refs can be cruel here.

Fuel scoops cannot directly refill cargo fuel tanks, either Collapsible or Internal , at the same time as main tanks. Fuel is scooped into the main tank then transferred to the cargo fuel tanks but is limited by the fuel transfer rate in the case of collapsible tanks.

This means a ship with cargo fuel tanks needs to scoop fuel twice, once to fill the main tanks then again after fuel has been transferred to the cargo fuel tanks. If the ship carries more fuel in cargo than it does in its main fuel tanks it may need to scoop fuel three or more times. Each 1-6 hours of scooping will bring in as much fuel as the ships main tanks hold.
For example a ship takes 1-6 hours to refuel using its scoops at a gas giant or source of water. With Internal demountable tanks up to the size of the ships main tanks the ship simply takes another 1-6 hours to fill the internal tanks after the first 1-6 hours is used to fill the main tanks. This is done as a single long scooping operation. A ship with internal tanks up to twice its main fuel volume will take 3D hours etc.

With collapsible tanks the ship needs to transfer the fuel from the main tanks into the collapsible fuel bladder and then scoop again to fill the main tanks. A Free Trader with 22 tons of main fuel and 22 tons of collapsible fuel tanks and no extra fuel handling ability must spend 1-6 hours scooping fuel, half a day transferring the fuel from the main tank to the collapsible tank and then another 1-6 hours scooping again to fill the now empty main tanks.

Fuel purification works as normal with Internal demountable tanks but with Collapsible tanks is limited to the fuel handling capacity if this is lower than the fuel processor rate since the purifier is connected to the main fuel tanks and the unrefined fuel in a bladder must be transferred to the purified to be processed. .

Collapsible tanks cost Cr500 per ton of tank capacity to make. Internal demountable tanks cost Kcr1 per ton of tank capacity to make. Fittings cost Kcr10 per ton.

Collapsible tanks are built to fit the cargo bay of a single type of ship and can only be used in another ship of the same make, this limits the resale value but as they are intended to be permanent additions to a ship this is not usually a problem. They can be made on any Class A or B starport.
Demountable tanks can be made new and stored when not in use which either Cr100 per ton per month in unsecure storage (a yard somewhere with no more than a simple fence) or Cr200 per month in secure storage (a lockable and guarded warehouse). Used Demountable tanks can be bought and sold as speculative cargo with the same modifiers as advanced manufactured goods. Merchant prince page 99, item 23, Cr1000 per ton. They can be made on any Class A or B starport or found anywhere advanced manufactured goods are traded in lots of 1D x 30 tons.

For example. A Far Trader crew wish to move from a trade main to a small cluster of worlds as part of an adventure. The nearest worlds in the cluster are four parsecs away so they need to make two jumps. They can either buy 44 tons of internal demountable tanks or buy a collapsible tank of 44 tons capacity. The internal Demountable tanks can be stored at the starport or sold when they reach the cluster and they will be at full cargo capacity but must return to this world to collect the tanks or try to buy replacements for the return jump. A collapsible tank costs less but will take up 3 tons of cargo when collapsed. Such a tank is always available which could be useful if it becomes important to leave the cluster quickly. Because of the small volume of fuel they decide not to add fuel handling capacity.

They decide to buy collapsible tanks for Kcr22 and then have the ship’s engineer fits them which will take on average 30 hours, the entire crew of 4 help with the engineer making a roll with 2 successes. So the total installation takes 5 man hours per 10 tons or 25 man hours, just over 6 hours with the whole crew helping.

They the buy a full load of fuel at the starport and head out to the jump point. After one jump into open space they spend a day transferring the fuel and then jump again into the cluster. On arriving they land at the starport and the ships engineer takes the collapsible tanks down and tucks them in a corner of the cargo bay where they take up 3tons.
After some adventures they decide to leave the area without delay. The crew assemble the collapsible tanks taking 10 hours this time as the pilot is on the bridge and the engineer had no successes to speed up the work. Scooping from a gas giant to fuel ready for the trip home takes 1-6 hours then a day to transfer the 44 tons from the main tank into the bladder then another 1-6 hours to scoop the main tanks full. So after almost two days they are ready to jump back towards home. But they were able to do this without going near the starport or attracting any notice.
Note these tanks are not new, versions of them have been covered in previous versions of Traveller. They are included here for completeness and for the many Mongoose players who are new to Traveller.