[Crazy Idea Time] Folding Starship

[PsiTraveller]

You can take a Drop Tank through with you if you want.

1st edition: The jump performance for the ship is calculated assuming that the drop tanks are not attached unless the jump is to be carried out without jettisoning the drop tanks. In this case, the jump
performance should be calculated in a similar manner to the effective M–Drive rating. pg 44

2nd edition: March Version: pg 39 "The jump capability of the ship does not need to be recalculated, unless it jumps with the drop tanks attached"

So you can take it with you, you just have to calculate the tonnage effect on Jump range. So a J4 ship could take 1400 tons Jump 2 for 280 tons of fuel. This allows a J4 ship to J2 hop and refuel at each stop and then leave the Drop Tank behind and do a Jump 4 when it wants. Because sometimes you want the extra range.

Sorry for the confusion about the example you gave. You wrote (in reference to my example) " A 1000 ton ship, J4 with 20 ton fuel in its 420 ton internal tank and a 400 ton loaded drop tank has enough fuel for one (1) jump. It will need to refuel the internal tank (the drop tank has been dropped) at the destination to jump again. If the internal was filled at the last system, it could jump again when prepped for another jump."

So your example has 420 tons internal fuel and a 400 ton Drop Tank, and I missed the last section about being filled at the last system which makes me look like a doofus. We agree on the use of Drop Tanks.

You can Jump with Drop Tanks attached, and not use the Drop Tank Collars that launch the Drop Tanks off the ship. You do not have to add the tonnage in the design, you just have to take the tonnage into account when you Jump. So the J2 jumps with tanks attached are a useful way of hauling a Drop Tank to the desired system. This is especially true if you are bringing a TL 14 Drop Tank along because it will survive the Jump separation. You will need a crew behind in the old system to grab it.

Adding Larger engines is an excellent way of taking advantage of situations where you need to move a little bit more material. It is awesome for a ship that is engaged in salvage or piracy and the movement of ships.

Let's look at the 1000 ton ship we've been discussing. In 2nd edition the engine size for a Jump 4 is 10 percent of the total tonnage moved, plus 5 tons. So the engine size would be 105 tons. But suppose you size the engine to be 125 tons. You can now move 1200 tons of material for the addition of 20 tons of extra Jump engine.
Next you add 2 tons of Jump Net from page 42 and that lets you net up 200 tons of captured ship, or cargo containers, or fuel pods and take them with you. Heck you could bring 200 tons of cargo containers and at Jump 4 they would be worth 1.4 million Credits in shipping fees. That would quickly pay back the 35 million in extra engine costs.
If you are a pirate and capture a 200 Free Trader, overpower the crew and capture the ship you could Net the ship and steal it and grab 45 million credits worth of ship.
For Trading vessels the use of external cargo mounts can also take advantage of oversized engines for extra income.
Docking Clamps also work for this.

Oversizing the engines can help in many situations. If you can grab a ship and carry it away with you you do not need to divide you crew into different ships. This can reduce the risk of prisoners retaking a ship and overpowering a skeleton crew.

 

[Reynard]

Unless your ship's prime mission is jumping, you're just loading a ship with fuel and engines taking a LOT of space from other components. You're not much of a trading vessel if you gave up the majority of cargo space for a 'creative ' use of drop tanks.

And who is this crew and ship that follows just in case you might want to drop those precious tanks you're adverse to dropping? It just sounds extremely convoluted (and expensive) for a tiny boost in range.

 

[PsiTraveller]

I'd argue that every starship's prime mission is Jumping. And using a Drop Tank allows for the increase of cargo carried per Jump. An empty fuel tank does not make money for the ship, yet every trip begins with the tank being emptied and that empty volume is carried in the form of the empty internal tank through Jumpspace to the destination. So the 1000 ton J4 cargo ship has 400 tons of empty tank at the start of its time in Jumpspace, the fuel has been used to create the Jump Bubble.

A Drop Tank allows that 400 tons to be turned into cargo space. This represents a huge boost in carrying capacity, at the expense of relying on an infrastructure in each system. There would need to be a tender ship that grabbed to empty Drop Tank and returned it to the Starport. This is absolutely true as you pointed out. My position is that a trading company would be interested in putting such a network in place because of the payoff of such a system. And unless the players are operating in the Wilds beyond the reach of civilization there is a strong case to be made to put such a system in place. There are Starports listed in every system in the Imperium. In reading the Starport section of Highguard each Starport is assumed to have a Drone fleet in place for automated fuelling and processing. Why is the infrastructure of a Starport expected in every system but the addition of a Drop Tank collection system a huge surprise?

The increase in engine size takes advantage of the engine to tonnage ratio. A small increase in engine size pays huge dividends for a ship. I am starting a new thread that involves tricking out a Far Trader in 2nd edition to take advantage of all the various technologies to increase profit. (and my apologies for hijacking this thread)

 

[Condottiere]

Starships tend to be self-contained, which usually means the captain and the chief engineer have a fairly good idea if it's functioning properly.

Which you desperately want it to do, considering the fact that if you fall adrift in jumpspace, no one coming to rescue you. You might survive a misjump.

Since you want the drop tanks to be standardized and regularly overhauled by competent maintenance personnel, you would have to create a fairly extensive regional organization.

 

[PsiTraveller]

I think a trading line would set up a series of posts that served their ships. They would provide the fuel and maintenance to their own ships. The infrastructure would be paid for by the increased income of the trading line.

My math is this. Assuming you pay 500 credits for refined fuel each ton of space you save that can make more than 500 Credits is extra income.
On the 1000 Ton J4 ship needed 400 tons of fuel. The 400 tons of space the fuel filled up is worth 7000 Credits per ton income instead of a 500 Credit cost. So paying 500 Credits for fuel for the 400 Tons of Drop Tank makes the ship money. Heck pay 1000 Credits per ton to cover the cost of the tender ship and crew and you are still making 6 times the income, spend 1000 Credits to make 6000 Credits.

The same works for J2 ships at shorter Jumps. A Far Trader needs 40 tons of fuel to Jump 2. If you used a Drop Tank instead and moved 40 tons of cargo the cargo area is worth 1600 Credits per ton. So spending 1000 Credits to make 1600 credits is still a profitable idea.

For the Tender side of the equation the numbers are still great. Cost of ice or water is listed at 75 Credits per ton, refining it and selling it at 500 Credits per ton quintuples the money. Someone on the boards made a skimming and processing ship that brought the cost per ton of refined fuel down to around 10 Credits a ton. This means multiplying your money by 50. As a starport manager I would be willing to tender ships for a 490 Credit a ton profit, especially when they need my fuel every jump.

 

[AnotherDilbert]

I agree with PsiTraveller. You gain lower costs for a smaller hull and increased flexibility with external carrying capacity. What's not to like?

 

[Reynard]

How did you come up with that cargo capacity logic? A fuel tank (and dismountable tanks and fuel bladders) are for fuel only. They don't have doors so you can switch back and forth at will. Dismountables have to be broken down to be cargo holds at 4 weeks. You have no choice in the function of a fuel hold. You carry jump fuel and use it at Jump. Too bad for the empty tank, that's the price paid to have a starship. Also you can't fuel up the jump drive then have cargo transferred on board before jump occurs. That's the problem the drop tanks face during jettison.

A drop tank diminishes your cargo capacity by adding component tonnage (4% of the drop tank tonnage) to a ship's internal structure. It seriously reduces efficiency when dragged into jump space since you no longer have full jump capability so why would two jump 2s, each taking a week, be better then a single jump 4? Plus your ship is slower in real space and degrades in configuration, streamlined to partial or partial to none. That mean your ship is restricted in it's flight and refueling capabilities. Time is money.

"The increase in engine size takes advantage of the engine to tonnage ratio. A small increase in engine size pays huge dividends for a ship."

Your 1000 ton J4 ship has a 100 ton Jump drive. Adding the 400 ton drop tank means you remove 40 extra tons from the ship for the larger drive. Most likely from cargo needed for paying for stuff. By the way, your 400 ton drop tank needs to be 560 to accommodate the bigger jump engine. You are losing cargo by the minute.

This is why the main purpose is for the military focusing on assault vessels who are fast, lean outfits without backup in tankers. They go in, perform the lightning strike then, if necessary, jump out with full tanks refueling from support ships back home. No wilderness refueling. This is why there are nit drop tanks on every Free Trader and tank recover services at every station.

 

[PsiTraveller]

If you remove 400 tons of internal fuel tank and replace it with 398 tons of cargo space and 1.6 tons of Drop Tank Connector you can Jump to the next system carrying 398 tons of cargo. This leaves the Drop Tank behind in the first system. In order to leave you would need to get a new Drop Tank. This model of ship would have no internal fuel tank.

If you wanted the ship to have internal fuel tanks then yes you would lose the 1.6 tons of space on the ship from somewhere else (the cargo space it had before for example). Using a Drop Tank you could then Jump into the target system with full fuel tanks, while leaving the Drop Tank behind.

If you want to bring the Drop Tank with you, you need to have Jump engine capacity to move the extra 400 tons of volume the tank represents. This would be 40 more tons of space for a Jump 4. Or the 1400 total tons the 1000 ton ship + 400 ton tank could jump a shorter distance with the same size Jump Engine. The 1000 ton ship has 105 tons of Jump Engine on it. At 1000 tons that represents 10 percent of the ship volume, Jump 4.

The 100 tons of Jump Engine in ratio to the 1400 tons of Ship + Drop Tank is 7.1%. Jump 3 needs 7.5% so we cannot Jump that far. Jump 2 needs only 5% of volume, so the ship could jump 2 parsecs, using 280 tons of fuel in doing so. This fuel could come from the Drop Tank, or the Internal tanks, or a mix of both. In this scenario you do not drop the Drop Tank.

We never established what cargo capacity a "regular" J4 ship would have. Let's pick 100 tons of cargo so we can all talk about the same ship.

So: 1000 Ton J4 ship
400 tons Jump fuel needed for J4 Jump.
100 Tons cargo
105 Tons of Jump Engine
Extra tonnage of fuel for 1 month of power plant. Let;s say 20 tons

If you get rid of Jump Fuel then you get 1000 ton ship J4 engine
105 Ton Jump Engine
20 Tons Power Plant Fuel
No Jump Fuel
1.8 tons Drop Tank Connector
98 Tons cargo (Drop Tank Collar comes from this space)
+400 Tons of cargo space that used to be a fuel tank but the ship has been designed that that space is now cargo.
Total cargo is now 498 tons of cargo.

This ship uses a Drop Tank every time it Jumps and Jumps 4, leaving the Drop Tank behind.

If it wants to bring the Drop Tank with it it connects the 400 Ton Drop Tank to the 1000 ton ship and Jumps 2, using 280 Tons of Fuel in the process, and bringing the Drop tank with it. As well as the 498 tons of internal cargo.

That's the advantage of the system, You redesign the ship to have the space that used to be a fuel tank be used as cargo space.
Now you could spend a month and convert the cargo space back into fuel space using Demountable tanks, or collapsible tanks. But you do not have to if the Tender ships and Drop Tanks are in each system,

 

[phavoc]

Missing from the equation is the cost of leasing or renting the tank. Since it external you can't use your own fuel processors to refine it, so your fuel costs jump from 100 to 500cr per ton. You also would have include the capitalized cost of the tank, servicing crews and ships, plus orbital support facilities.

A regular shipping line might find this to be advantageous, since with enough volume it can own all of the tanks and servicing equipment.

I would suspect that you would need tanks of a generic size and shape to fit various types of ships.

A question would be if you only need 40 tons of fuel, and the only tank available was 100 tons, could you use the 100 ton tank? How, or could, a larger tank possibly affect jump operations, since the 100D limit applies to local space objects with enough mass (admittedly an empty tank has the same volume but less mass empty vs. Full).

And would it fit right against your ship? And if it did, what exactly on your ship would be occluded and not able to function well, or at all?

 

[Tenacious-Techhunter]

Now who’s complaining about blindspots?

 

[Condottiere]

Needs an actual business plan, not that Traveller economics makes much sense at the best of times.

 

[PsiTraveller]

What price do you want to charge for the Drop Tank service?
Fuel is 500 per Ton, I will pay that no problem. Your cost is 100 per ton, making you 400 Credits profit per ton, assuming you do not have AnotherDilbert's Ocean fuel skimmer where the cost per ton was around 9 credits per ton. http://forum.mongoosepublishing.com/viewtopic.php?f=89&t=118716&p=899759&hilit=fuel+skimmer#p899759

The J4 Cargo ship needs 400 tons per jump. That is 200 000 Credits to you per Jump, and 160 000 Credits profit for fuel sales.

Charge me another 500 Credits per ton for the Drop Tank Tender Charge. I will pay it no problem.

The economics for me are simple. At jump 4 the cargo payment is 7000 Credits per ton. If I pay 1000 Credits per ton for Drop tank service, the 400 tons of cargo space I gain is worth 2.4 Millions Credits profit to me per trip. At Jump 3 the cargo payment is 3000 Credits per ton, so a 2000 Credit per ton profit to use a Drop Tank service.

Jump 2 is 1600 credits per ton, so only a 600 Credit profit to pay 1000 credits per ton for Drop Tank service. This is still an advantage to me even if you double the cost of my fuel.

The thing to remember is that the empty space an internal fuel tank represents during a Jump makes no money for the ship. The tanks are emptied at the start and remain empty during the trip. They are simply a cost. The Drop Tank changes that paradigm and drops the cost and turns it into a profit. 400 tons of cargo makes more money than 400 tons of empty space. Empty space makes you nothing. Cargo is income. If the cost for fuel and Drop Tank service is less than the income from shipping, you are making money.

Now this is only workable at TL 14+. Paying for a new Drop Tank at 25 000 Credits per ton every trip is too expensive. TL 14 the Drop Tank is reusable.

 

[Reynard]

I'm assuming your fuel profits are based on you skimming free fuel or converting water and ice. Remember those permanent drop tanks make your ship maneuver like a garbage scow so gas giant skimming and planet landing becomes hazardous if not impossible depending on your ship's original configuration. You may be forced to depend on highports for fuel. I assume In Your Universe every ship is fitted with drop tanks so there would be a reason every starport runs regular drop tank services? That means there are a lot of garbage scows out there and fewer downports.

Saying drop tanks make internal tanks useless is odd as it still adds to the overall ship tonnage which can greatly reduce jump and maneuver efficiency, adds tonnage for pumps and connections and reduces configuration efficiency. Just maybe internal fuel tanks are not such a cost.

 

[PsiTraveller]

I am assuming that I would be buying fuel and the Drop Tank service from the Highport OR I would have a system based ship of my own company that did the Drop Tank service for me. I admit this is an added level of infrastructure. I think the profits from increased capacity would pay for it. I think a highport would want to offer a Drop Tank service because it offers a means to always sell refined fuel and cuts down on ships that do skim gas giants.If I was a Highport and selling fuel at a 400 credit per ton profit (or more), I would want to offer services that made more people buy my fuel.

Drop Tanks do make your ship slower using M-Drive, no doubt about it. Drop Tanks only change your Jump efficiency if you take the Tank with you during the Jump. The J4 ship would have J2 when trying to move the added 400 tons. If you dropped the tank the ship could move J4, and will have moved only 1000 tons of ship doing so, 500 tons of which would be cargo worth 3.5 million credits. You would need a drop tank service in each system, but would quintuple your income from each jump.

 

[Reynard]

If I understand you correctly, these ships have no internal jump fuel and rely on drop tanks exclusively for jumps (and they must be TL 14+) then must replace the tanks at the next destination. That means more than likely routes would have to have highports meaning Class A and B and 50% of Class C. This would also explain such startports being able to even considering drop tank services. Depending on whether these specialized ships are serviced by the corporation who runs them or if the authority running starports sector or principality wide for a general ship population. The drop tank service would need to retain a HUGE assortment of drop tanks for any possible ship size using them OR these are, in fact, specialized and standard size and design.

Does this sound like you're creating an Express Trade Boat system?

All this purpose built infrastructure and restrictive design parameters sound expensive. The only ones coming close to breaking even would be a corporate entity running frieghters of this design rather than traders which rely more on going places a freighter can't. Before stopping at the ship, you may have to also add in drop tank facilities to a station plus the large numbers of drop tanks for service plus the ships to support the operations including retrieval. Speculative trade could be considered too cost inefficient since most operation occur on limited routes and limited access. All these would become higher fees towards the operation of the ship.

 

[PsiTraveller]

The infrastructure is expensive, but I think I can make case for profitability. I am making a lot of assumptions, like having enough cargo to fill 500 tons a trip for a Jump 4 journey. At 7000 credits a ton this eliminates shipping low value goods. You can still make money charging less for lower value freight.

The bottom line is that if the cost of fuel and the Drop Tank service is less than you get paid to ship something, you make money shipping it. This could provide a job for a coworker living in each system running a ship that provides fuel and Drop Tank service, or simply paying the Highport a fee for fuel and Drop Tank service. If the income is greater than the cost you make money. In some cases with a full load, enough money to pay for things for weeks or months on a single trip.

 

[Condottiere]

I'm sure I;m not the only one that thought of the droptanked X-boat.

 

[Reynard]

Remember that x-boats don't maneuver. They exit and wait for pickup. Service and refuel then jump again. Adding drop tank components adds tonnage. I think they're already as lean as you can get.

 

[phavoc]

The infrastructure is expensive, but I think I can make case for profitability. I am making a lot of assumptions, like having enough cargo to fill 500 tons a trip for a Jump 4 journey. At 7000 credits a ton this eliminates shipping low value goods. You can still make money charging less for lower value freight.

The bottom line is that if the cost of fuel and the Drop Tank service is less than you get paid to ship something, you make money shipping it. This could provide a job for a coworker living in each system running a ship that provides fuel and Drop Tank service, or simply paying the Highport a fee for fuel and Drop Tank service. If the income is greater than the cost you make money. In some cases with a full load, enough money to pay for things for weeks or months on a single trip.

You bring up very valid points. I haven't run all the numbers, but it does seem like long-range freight would be a literal gold mine. And by doing so every Tom, Dick and Solarian would be doing it, which in theory should drive down the price. Of course with this being a game, those things don't have to be taken into consideration. I think it would be difficult to allow PC's to do simply because it would mean money is no longer an issue - they could do this for a year and be rich and retire.

 

[NOLATrav]

I think it would be difficult to allow PC's to do simply because it would mean money is no longer an issue - they could do this for a year and be rich and retire.

Or Tukera, Oberlindes and Akerut all start noticing and use more aggressive trade policies on the PCs' routes... couple of pulse laser hits here and there and you could easily bleed off a few million Cr in repairs every couple jumps. Or a small bomb in a cargo container, knocks a little hole in the ship and destroys 100 tons of cargo. Or a high passenger that's actually... you get the idea.