2000 J4 Drop Tank Cargo Hauler

[PsiTraveller]

Rough Cut of a J4 capable ship that is focused on the 7000 Credit/ton J4 freight traffic.
The ship is 800 tons of Engines and crew space with 1200 tons of cargo capacity on external cargo mounts.
The ship carries fuel for its M-Drive, but uses TL 14 Drop Tanks to supply the 800 tons of fuel it needs to get to the next system. Tender ships or Drones retrieve the Drop Tanks after the ship leaves the system. The ship is a TL 14 design.

Crew Section: 800 Tons: None Streamlined since the Cargo Mounts will prevent any streamlining. Close or Sphere offers a cost savings, as does light hull. This is an option. I will ignore any price modification and use Standard cost.
800 tons 40 MCr
no Armour
J Drive: budget: 2000 Ton Build J4 205 tons costing 230 MCr: 150 Diameter disadvantage
M-Drive budget: 2000 tons Thrust 3:
Power Plant: Odd question here. I have 121 tons budgeted for1815 points. this is using basic power needs for a 2000 ton ship, but I have 1200 tons in External mounts. Does this need power?
13 Tons of Power Plant Fuel
40 Ton Bridge
TL 9 Rating 40 Computer
20 Tons for Triple Turrets
25 Staterooms, 20 Low Berths: Crew of 18, 1 Jump Pilot, Astrogator, 9 Engineers, 2 Mechanics, 4 Gunners and a Medic, 1 Shuttle Pilot
Ships Hangar for Ships Boat,
Ships Hangar for cargo pod from 1st edition Traders and Gunboats to handle the cargo pods on the External Mounts.
Medical Bay, Library, Workshop
3.2 tons of Drop Tank Collar and mounting gear. (.4% of 800 tons)
1200 tons of External Cargo Mounts, costing 1.2 Million Credits, but no tonnage in and of itself?

Software will be Jump 4, plus Virtual Crew and Fire Control and Advanced Fire Control.
I have 30 ish tons left to handle any slipups in tonnage.

The cost of the ship is around 700 MCr, which includes 20 million for the Drop Tank. Making it a Light Hull would cut the cost by 25%. The design is to show the profitability of the Drop Tank freighter.

Income would be 1200 tons times 7000/ton, or 8.4 Million a trip, 16 million a month. Additional costs for the Drones and fuel system in each system, but the ship was put together on the fly to point out the 5 million credits worth of cargo space the Drop Tank frees up.

 

[AnotherDilbert]

Nice! I was thinking about something like this the other ay.

Power Plant: Odd question here. I have 121 tons budgeted for1815 points. this is using basic power needs for a 2000 ton ship, but I have 1200 tons in External mounts. Does this need power?

By my understanding of the rules, no. You have chosen a 800 dT hull, you only need basic power 800 dT. You are only providing gravity and life-support for those 800 dT.

The drives on the other hand should probably need power as for a 2000 dT ship, when they are used to move a 2000 dT object.
Note that when the drop tanks are mounted the M-drive is thrust 2 and needs power as a thrust 2 for a 2800 dT object.


The crew requirements are open to interpretation, they say "per ton of ship", not "per ton of Hull". I would argue that you need crew for a 800 dT ship.

 

[AnotherDilbert]

The cost of the ship is around 700 MCr, which includes 20 million for the Drop Tank. ...

Income would be 1200 tons times 7000/ton, or 8.4 Million a trip, 16 million a month. Additional costs for the Drones and fuel system in each system, but the ship was put together on the fly to point out the 5 million credits worth of cargo space the Drop Tank frees up.

This nicely illustrates that the drop tanks must be recovered and reused.

 

[phavoc]

Drop tanks can be shredded by the jump. Is the cost of replacing them included in your operational model? In theory your ship is restricted to routes that have the necessary infrastructure to provide new drop tanks and fuel at each end of the route.

This seems to me a violation of the concept behind drop tanks. Even X-boats carry their own fuel, but no maneuver drives. I know it's allowed by the rules, but I do hope they plug this hole.

 

[AnotherDilbert]

Drop tanks can be shredded by the jump.

The ship is a TL 14 design.

At TL14, the use of drop tanks has improved to such a degree that drop tanks will automatically survive use.

In theory your ship is restricted to routes that have the necessary infrastructure to provide new drop tanks and fuel at each end of the route.

Nothing theoretical about it, unless the drop tank is very small it has to be made at a starport type A or B of the appropriate TL. It then has to be transported to the place you want to jump from. Drop tanks can only be used on the major shipping routes. A free trader cannot.

 

[phavoc]

Drop tanks can be shredded by the jump.

The ship is a TL 14 design.

At TL14, the use of drop tanks has improved to such a degree that drop tanks will automatically survive use.

In theory your ship is restricted to routes that have the necessary infrastructure to provide new drop tanks and fuel at each end of the route.

Nothing theoretical about it, unless the drop tank is very small it has to be made at a starport type A or B of the appropriate TL. It then has to be transported to the place you want to jump from. Drop tanks can only be used on the major shipping routes. A free trader cannot.

Yeah, you should be able to re-use them. I keep forgetting about the TL14 and above you get to re-use them. And, I suppose, it's possible to ship in the equipment to a lower TL system, and you have the tugs and additional drop tanks waiting.

 

[PsiTraveller]

I absolutely agree that this would be a megacorporation design on settled safe routes. This brings in the most money and leaves the lesser routes for those poor sods who lack the infrastructure and capacity to have tenders and production units for tanks that get lost or damaged. The off route stuff is for smaller ships with internal tanks who have to bring in the goods from the feeder routes out in the lesser developed wilds.

This system would also be useful for military transport of goods from base to base since the infrastructure is there to support it. For a military operation it could move a lot of materiel forward, but unless someone brought in more Drop Tanks, or they could be manufactured in the captured system the system would stall out. Unless you had one ship carry one tank forward, then a back and forth chain could be developed. Every new tank that is brought in allows another ship to start moving back and forth along the supply chain.

Tl 14 helps with the survivability of tanks as mentioned above. For bigger ships you need a massive investment up front to make it pay off down the road.

 

[phavoc]

Rough Cut of a J4 capable ship that is focused on the 7000 Credit/ton J4 freight traffic.
The ship is 800 tons of Engines and crew space with 1200 tons of cargo capacity on external cargo mounts.
The ship carries fuel for its M-Drive, but uses TL 14 Drop Tanks to supply the 800 tons of fuel it needs to get to the next system. Tender ships or Drones retrieve the Drop Tanks after the ship leaves the system. The ship is a TL 14 design.

Crew Section: 800 Tons: None Streamlined since the Cargo Mounts will prevent any streamlining. Close or Sphere offers a cost savings, as does light hull. This is an option. I will ignore any price modification and use Standard cost.
800 tons 40 MCr
no Armour
J Drive: budget: 2000 Ton Build J4 205 tons costing 230 MCr: 150 Diameter disadvantage
M-Drive budget: 2000 tons Thrust 3:
Power Plant: Odd question here. I have 121 tons budgeted for1815 points. this is using basic power needs for a 2000 ton ship, but I have 1200 tons in External mounts. Does this need power?
13 Tons of Power Plant Fuel
40 Ton Bridge
TL 9 Rating 40 Computer
20 Tons for Triple Turrets
25 Staterooms, 20 Low Berths: Crew of 18, 1 Jump Pilot, Astrogator, 9 Engineers, 2 Mechanics, 4 Gunners and a Medic, 1 Shuttle Pilot
Ships Hangar for Ships Boat,
Ships Hangar for cargo pod from 1st edition Traders and Gunboats to handle the cargo pods on the External Mounts.
Medical Bay, Library, Workshop
3.2 tons of Drop Tank Collar and mounting gear. (.4% of 800 tons)
1200 tons of External Cargo Mounts, costing 1.2 Million Credits, but no tonnage in and of itself?

Software will be Jump 4, plus Virtual Crew and Fire Control and Advanced Fire Control.
I have 30 ish tons left to handle any slipups in tonnage.

The cost of the ship is around 700 MCr, which includes 20 million for the Drop Tank. Making it a Light Hull would cut the cost by 25%. The design is to show the profitability of the Drop Tank freighter.

Income would be 1200 tons times 7000/ton, or 8.4 Million a trip, 16 million a month. Additional costs for the Drones and fuel system in each system, but the ship was put together on the fly to point out the 5 million credits worth of cargo space the Drop Tank frees up.

So, if your main body is 800 tons, and your cargo is 1,200 tons, where does the additional 800 tons of jump fuel get factored in? Wouldn't that make this a 2,800 ton craft?

Also, since your core craft is only 800 tons, you only get 8 hardpoints. A tug-craft doesn't get to use the tonnage for the external cargo (or drop tanks) to calculate hard points. That's for the ship tonnage itself.

 

[PsiTraveller]

This uses Drop Tanks that actually drop off each Jump, so the 800 tons of fuel does not get calculated into the tonnage equation. Total volume of transport is the 800 tons of living area and 1200 tons of cargo.
The ship likely has only 8 hardpoints as the 1200 tons of cargo mounting in my mind would not be useful for turrets or other hardpoint uses.

This ship is for moving a lot of cargo at J4 without a thought towards combat. The inspiration was the L-Hyd example posted from the old TAS article.. The ship moves the most cargo it can by not taking a fuel tank along with it on the trip (aside from Power Plant fuel supply). Since each ton of cargo is worth 7000 Cr it makes more money than ships that arrive with an empty fuel tank.

The downside is that there needs to be a system in place to replace the Drop Tank in each system.

 

[phavoc]

This uses Drop Tanks that actually drop off each Jump, so the 800 tons of fuel does not get calculated into the tonnage equation. Total volume of transport is the 800 tons of living area and 1200 tons of cargo.
The ship likely has only 8 hardpoints as the 1200 tons of cargo mounting in my mind would not be useful for turrets or other hardpoint uses.

This ship is for moving a lot of cargo at J4 without a thought towards combat. The inspiration was the L-Hyd example posted from the old TAS article.. The ship moves the most cargo it can by not taking a fuel tank along with it on the trip (aside from Power Plant fuel supply). Since each ton of cargo is worth 7000 Cr it makes more money than ships that arrive with an empty fuel tank.

The downside is that there needs to be a system in place to replace the Drop Tank in each system.

I asked because you had this listed in your build - "20 Tons for Triple Turrets". 20 tons implies 20 hardpoints, not 8.

Ok, so this design is dropping the tanks at jump. In the other thread it got me wondering about people adding drop tanks and bringing them along wherever they go. Which defeats the purpose of the drop tank, cause ya ain't dropping it.

 

[PsiTraveller]

My mistake on the design listing 20 tons for turrets, it should be 8. Like I posted, it was a rough cut figured out while I was typing the posting up. I should take more time and edit more.

Removable tanks allow for a massive increase in speed for combat, as well a reduction in cost and power needs for the engines.
Example: 1000 ton ship with internal fuel tanks wanting Thrust-9 for combat needs 90 tons of M-Drives (9% of 1000 tons). 2MCr per ton and that costs 180 MCr.

But if you were willing to give up the 4 hardpoints and NOT take a fuel tank into combat then you use a removable fuel tank that you carry with you through Jump Space and release before combat. Your 600 ton ship now needs 54 tons of Drives to have Thrust 9. When the tank is attached the ship will have M-Drives representing 5.4% of the volume and the 1000 ton ship will have Thrust 5.

The 54 tons of M-Drives cost you 108 MCr, a savings of 72 MCr.

The naming of a Drop Tank you do not drop when Jumping is a bit confusing. I like the Camel hump system, or the Removalable External Demountable Tank, Redit for short. But Tactically the Drop Tank collar technology is good if you want a fast getaway and change from Thrust 5 to Thrust 9.

If you want to use a Drop Tank system and keep all your hardpoints then you build a 1000 ton warship of the Cortes Class with a mounting collar for a regular Drop Tank and the 90 tons of Drives, and no internal fuel aside from Power Plant and fighter fuel. The ship then Jumps into the enemy system and cannot get away unless they are able to get a new Drop Tank to keep moving. I use Cortes as the name since he scuttled his ships to ensure his troops were motivated to win. There is no going back unless victory.

In a big fleet invasion you may be taking in larger ships with construction decks on them that make new tanks as you go using captured material. Heck a new naval doctrine may create a massive logistical train that can invade a system with asteroids or minable moons and make what you need on the move. We are looking at technology that has automatic mining drones and fueling drones in the Spaceport chapter. Some bright person will figure out a way to weaponize it.

 

[phavoc]

My mistake on the design listing 20 tons for turrets, it should be 8. Like I posted, it was a rough cut figured out while I was typing the posting up. I should take more time and edit more.

Removable tanks allow for a massive increase in speed for combat, as well a reduction in cost and power needs for the engines.
Example: 1000 ton ship with internal fuel tanks wanting Thrust-9 for combat needs 90 tons of M-Drives (9% of 1000 tons). 2MCr per ton and that costs 180 MCr.

But if you were willing to give up the 4 hardpoints and NOT take a fuel tank into combat then you use a removable fuel tank that you carry with you through Jump Space and release before combat. Your 600 ton ship now needs 54 tons of Drives to have Thrust 9. When the tank is attached the ship will have M-Drives representing 5.4% of the volume and the 1000 ton ship will have Thrust 5.

The 54 tons of M-Drives cost you 108 MCr, a savings of 72 MCr.

And your performance with your tanks attached is degraded because you cannot make that speed with that displacement and that sub-sized maneuver drive. Plus it's not clear if you can skim with an external tank (I'd say not, but I've never seen it mentioned anywhere). Regular fleet elements would be faster, at the now apparent standard 9G thrust.

The naming of a Drop Tank you do not drop when Jumping is a bit confusing. I like the Camel hump system, or the Removalable External Demountable Tank, Redit for short. But Tactically the Drop Tank collar technology is good if you want a fast getaway and change from Thrust 5 to Thrust 9.

If you want to use a Drop Tank system and keep all your hardpoints then you build a 1000 ton warship of the Cortes Class with a mounting collar for a regular Drop Tank and the 90 tons of Drives, and no internal fuel aside from Power Plant and fighter fuel. The ship then Jumps into the enemy system and cannot get away unless they are able to get a new Drop Tank to keep moving. I use Cortes as the name since he scuttled his ships to ensure his troops were motivated to win. There is no going back unless victory.

How so? I don't know the design, but you cannot count the tonnage for your tank for your ship's hardpoints (unless I'm mis-interpreting what you are saying here. If you are saying you would have 10 hardpoints, then we would be concuring with the calculations). If you built a 1,000 ton ship, you'd get 10 hardpoints. I'd also say that would not be allowed unless you have fanatical troops. Why? Because you don't run a navy, or a military that way. Not a normal one at least. As a former military person I can attest I would NOT follow leaders who where that stupid and/or fanatical. In Vietnam stupid leaders like that often got killed by their own troops. And the Imperial military is, more or less, well led.

In a big fleet invasion you may be taking in larger ships with construction decks on them that make new tanks as you go using captured material. Heck a new naval doctrine may create a massive logistical train that can invade a system with asteroids or minable moons and make what you need on the move. We are looking at technology that has automatic mining drones and fueling drones in the Spaceport chapter. Some bright person will figure out a way to weaponize it.

This is the battle rider concept. The drop tank fleet is trying to get the best of both worlds. Except you don't really. You are carting around excess tonnage for those drives when you don't need them if you had riders. And leaving your fuel tanks out, which are extremely fragile, means a single fighter that slips through your screens can stop your ship from retreating from the system.

The other thing is the economics of this. Let's use your hauler as an example. The drop tank mount will cost you MCr1 per 50 tons of fuel. So that means your 400 ton tank costs your 8MCr to start (plus maintenance per month). It also takes up 2 Dtons of space per 50 tons of fuel, so that's 16 tons of space being consumed.

Now you have the cost of the tank(s) themselves. It's Cr100,000 per 50 tons. So that's Cr800,000 per tank, and you need at least two to travel back and forth.

Cost wise you are still saving money, and with the tonnage space you can definitely make more money. But your model doesn't factor in the cost of having retrieval ships on both ends of your route. And you have to pay for those crews and maintenance (you'd need a tugship capable of hauling 400Dtons to move the drop tank). Once you start factoring in the other costs, the advantages start to trickle away. Now, if you have enough traffic for say a daily departure, and you used the exact same type of ship for each departure, you could, theoretically, get away with as few as three tanks on each side of the jump route to service 14 ships. Spreading the support costs across multiple vessels makes it more economic, but you also have multiple single points of failure that could disrupt your entire shipping route timing (the tug gets damaged, a tank is taken out of service for maintenance, a rival shoots a couple of holes in them, etc).

The idea has merit as a sort of LASH concept, except with fuel instead of cargo, but I think I would draw the line at it being a military combat version. With a battle rider you know your carrier ship is vulnerable, but at least you have a route to go home. With your version you are stuck and will either fight and win, or scatter and hope for a rescue. With enough fuel and supplies you could go to a rendezvous point way out-system and meet up with supply vessels with new tanks, but that also means you are no longer effective fighting units, and thus the enemy has a temporary advantage while your tonnage is uselessly tied up somewhere. And you better hope you don't get followed, waiting for you to lead them to your tanks and ruin your only chance of retreat.

I still think it's a cheat of the system. Easiest way to fix it is to remove the ability of tanks to survive the jump bubble. If there's a good chance they'll get destroyed with any jump it will return to being a useful tool for special missions, but nobody will use it on a regular basis - except players of course.

 

[AnotherDilbert]

And your performance with your tanks attached is degraded because you cannot make that speed with that displacement and that sub-sized maneuver drive. Plus it's not clear if you can skim with an external tank (I'd say not, but I've never seen it mentioned anywhere). Regular fleet elements would be faster, at the now apparent standard 9G thrust.

You can be partially streamlined with drop tanks, so can skim gas giants.

You are a little slower in real-space, but you drop the tanks before combat, so not encumbered in combat. The difficult trick is recovering the tanks after the combat, hoping the enemy haven't found them and destroyed them.

For scheduled commercial flights on major shipping routes it makes great sense to use drop tanks. Why pay to jump around empty fuel tanks?

 

[PsiTraveller]

Cortes Class is a name I made up to mention Cortes and the scuttling of his ships for the attack on Tenochtitlan.
https://en.wikipedia.org/wiki/Spanish_conquest_of_the_Aztec_Empire#Scuttling_the_fleet_and_aftermath
I am using the name Cortes to represent the concept of starting an attack without a means of returning unless you win. As phavoc mentioned this may require fanatical troops. I disagree with that idea. Paratroopers dropped behind enemy lines and faced death or capture if things went wrong, and they did not revolt against the leadership. Operation Marketgarden shows what can happen if things go wrong, but airborne operations still continued throughout the war. The soldiers in the spaceship might be closer in concept to a submarine crew operating in enemy waters. They are far from any aid but still fought on.

And I would also argue that a ship without Drop tanks is closer to an SDB in operation, with the capacity to Jump out if supplied with another tank. Another design option is to put J1 fuel inside the ship and allow the ship to Jump out 1 parsec to a FARP base. You still save 300 tons of extra space. What the Drop Tank allows is more capacity within the hull for more weapons, supplies, troops, etc.


The partially streamlined skimming has been covered by AnotherDilbert. Yes you are slower in space getting to a Jump point at Thrust 5 instead of 9. I am fine with that. Older Traveller had ships of Thrust 3 and 4 as standard, so it is still a win in my eyes.
There may be faster skimming ships that handle the skimming, The Manta ship from TNE acted as a mobile fuel tank and skimming system. There could be some creative designs and logistical calculations made and published in later products. For a Megacorp in a settled route and Spaceport refueling capacity this would be part of business.

The maintenance cost of the tank is something to consider, and the tender fleet needs to be detailed. The design concept was to see how much tonnage a J4 freighter could move through with a Drop Tank system. I think I will be looking at the X-boat Tender examples and some Drone examples and writing up a simple fueling system and freight terminal. At J4 your profit margin is 4000 per ton, so any cost that is cheaper then that allows you to make money.

The risk of having your tanks destroyed in combat is real, no question. You would need to either hide them, guard them, or make them more expensive and make them stealthy. It is a point that can be attacked that is true. Naval doctrine will be developed on both sides of the question to attack and defend the tanks.

Your cost and spacing of tank tonnage seems off to me. A 1000 ton J4 ship needs 400 tons of Drop tank. a 400 ton drop tank needs 1.6 tons of space in the hull. Page 39 of the Highguard pdf. 0.4% of tank tonnage is used for connectors. So you and I disagree on the amount of tonnage. I say 1.6 you say 16. But I would still argue that even at 16 tons of space for 400 tons of fuel is still a win, let alone 1.6


50 tons of fuel tank costs 1.25 million Credits, the 400 ton tank would cost 10 Million Credits. Drop Tanks cost 25 000 per ton of hull. Maintenance costs for the ship are listed on pg 145 as 0.1% of purchase price divided by 12. So 10 000 000 *0.1% is 10 000 Credits a year, 833 a month. Call it 1000 Credits a month. Money well spent in my mind.

As for the logistical baggage train, I agree it could be a problem, depending on how many ships you brought in with no internal tanks. The collar ships may be used as slightly weaker SDB's most of the time, with the capacity to act as Jump ships in support of an invasion.

Still using my 1000 ton concept. 10 hardpoints because we are using Drop tanks. J4 , so 90 tons of Jump drive, 1.6 tons of connecting collar. Heck, call it 100 tons or 10 percent of space lost to Jump capability. This leaves 900 tons for weapons and troops and M-Drives. This is 100 tons less than a normal 1000 ton SDB would have in capacity because of the 100 tons of Jump capacity.

In the event of an invasion these Jump capable ships could be dropped in to support operations of the larger ships They bring 40 percent more combat capacity to the battle than a 1000 ship with internal tankage. They have a logistical achilles heel with the need for tanks, granted, but this may well be offset by the ability to bring more tonnage per hull value then conventional forces. I don't know for sure, I have not done the math or playtesting. I am just putting ideas about implementing the technology out in front of folks. Is there a best design option for a Jump Collar ship? Will the technology be used for moving cargo only and not for military operations? I do not know. I am just having fun thinking about the possibilities.

 

[phavoc]

Cortes Class is a name I made up to mention Cortes and the scuttling of his ships for the attack on Tenochtitlan.
https://en.wikipedia.org/wiki/Spanish_conquest_of_the_Aztec_Empire#Scuttling_the_fleet_and_aftermath
I am using the name Cortes to represent the concept of starting an attack without a means of returning unless you win. As phavoc mentioned this may require fanatical troops. I disagree with that idea. Paratroopers dropped behind enemy lines and faced death or capture if things went wrong, and they did not revolt against the leadership. Operation Marketgarden shows what can happen if things go wrong, but airborne operations still continued throughout the war. The soldiers in the spaceship might be closer in concept to a submarine crew operating in enemy waters. They are far from any aid but still fought on.

That's not what paratroopers do. Paratroopers are a vanguard force, dropping in ahead of ground troops, or they are the main assault force. As history has shown us, sometimes leaders do gamble with their lives, but as a rule of thumb they don't get Cortesed. Neither do special operations units. But their jobs are dangerous, and like submariners, they know their jobs can lead to death. Those who serve know this. But they also realize that they aren''t cannon fodder (I'm speaking of Western militaries, modern ones. As we saw in WW2 you can get some very fanatical people depending on your society and if you are fighting on your own soil for the survival of your people).

And I would also argue that a ship without Drop tanks is closer to an SDB in operation, with the capacity to Jump out if supplied with another tank. Another design option is to put J1 fuel inside the ship and allow the ship to Jump out 1 parsec to a FARP base. You still save 300 tons of extra space. What the Drop Tank allows is more capacity within the hull for more weapons, supplies, troops, etc.

No, a SDB is a spaceship, NOT a starship. Battleriders are just big spaceships. The thing that sets them apart is their ability to move between star systems on their own

The partially streamlined skimming has been covered by AnotherDilbert. Yes you are slower in space getting to a Jump point at Thrust 5 instead of 9. I am fine with that. Older Traveller had ships of Thrust 3 and 4 as standard, so it is still a win in my eyes.
There may be faster skimming ships that handle the skimming, The Manta ship from TNE acted as a mobile fuel tank and skimming system. There could be some creative designs and logistical calculations made and published in later products. For a Megacorp in a settled route and Spaceport refueling capacity this would be part of business.

I'm not aware of the partial streamlining and fuel skimming being covered by any rule. Can either of you point me to that? I've always wished for more in-depth discussion on refueling in a gas giant. And, my most favorite question of all... why is it so damn dangerous to have a "high guard"??? There are no official rules laid out for this. I've had to go and try to fill in the gaps myself.

The maintenance cost of the tank is something to consider, and the tender fleet needs to be detailed. The design concept was to see how much tonnage a J4 freighter could move through with a Drop Tank system. I think I will be looking at the X-boat Tender examples and some Drone examples and writing up a simple fueling system and freight terminal. At J4 your profit margin is 4000 per ton, so any cost that is cheaper then that allows you to make money.

The risk of having your tanks destroyed in combat is real, no question. You would need to either hide them, guard them, or make them more expensive and make them stealthy. It is a point that can be attacked that is true. Naval doctrine will be developed on both sides of the question to attack and defend the tanks.

Your cost and spacing of tank tonnage seems off to me. A 1000 ton J4 ship needs 400 tons of Drop tank. a 400 ton drop tank needs 1.6 tons of space in the hull. Page 39 of the Highguard pdf. 0.4% of tank tonnage is used for connectors. So you and I disagree on the amount of tonnage. I say 1.6 you say 16. But I would still argue that even at 16 tons of space for 400 tons of fuel is still a win, let alone 1.6


50 tons of fuel tank costs 1.25 million Credits, the 400 ton tank would cost 10 Million Credits. Drop Tanks cost 25 000 per ton of hull. Maintenance costs for the ship are listed on pg 145 as 0.1% of purchase price divided by 12. So 10 000 000 *0.1% is 10 000 Credits a year, 833 a month. Call it 1000 Credits a month. Money well spent in my mind.

I was using 1st Ed rules. That's what I had access to. It could very well have changed in v2.

As for the logistical baggage train, I agree it could be a problem, depending on how many ships you brought in with no internal tanks. The collar ships may be used as slightly weaker SDB's most of the time, with the capacity to act as Jump ships in support of an invasion.

Still using my 1000 ton concept. 10 hardpoints because we are using Drop tanks. J4 , so 90 tons of Jump drive, 1.6 tons of connecting collar. Heck, call it 100 tons or 10 percent of space lost to Jump capability. This leaves 900 tons for weapons and troops and M-Drives. This is 100 tons less than a normal 1000 ton SDB would have in capacity because of the 100 tons of Jump capacity.

In the event of an invasion these Jump capable ships could be dropped in to support operations of the larger ships They bring 40 percent more combat capacity to the battle than a 1000 ship with internal tankage. They have a logistical achilles heel with the need for tanks, granted, but this may well be offset by the ability to bring more tonnage per hull value then conventional forces. I don't know for sure, I have not done the math or playtesting. I am just putting ideas about implementing the technology out in front of folks. Is there a best design option for a Jump Collar ship? Will the technology be used for moving cargo only and not for military operations? I do not know. I am just having fun thinking about the possibilities.

Maybe, maybe not. I enjoy designing things too. Seems like you are trading a lot of flexibility to basically make SDB's that can act as their own jump carriers. The middle of the road between riders and starships doesn't make a lot of military sense to me. You aren't as fully efficient as a rider, and you don't have the full capabilities of a starship. It works for some specialized things, but overall I don't see it working out for a large chunk of a navy.

 

[PsiTraveller]

As I've said, I am just testing out the technology that would allow a ship to jump more weapons per ton to support a J4 combat. Drop Tanks offer a means of doing that.
The flip side of the Drop Tank debate is to remove the tonnage, lose the hardpoints and gain Thrust value. Whihc is more important, more hardpoints vs speed, Jump capability vs logistical considerations? I am not sure. That is why I am posting ideas to the board, to get feedback. As I learn if the idea is good I adjust the things I make, correct mistakes and add it to my Drinax campaign, and to the bad Traveller fanfic I write.

This leads to the two different ideas being discussed with Drop Tanks right now. Do you have a removable tank so your "lighter" (less volume) is faster and you get the tank back after battle OR do you build a ship of 1000 tons full of extra weapons and use the Drop Tanks to send the more heavily equipped ship into the target system.

The name Cortes I picked because of the no turning back. I could have gone with the idea of a glider force, or something that echoed paratroopers, something one way. And I am not advocating that the troops are tossed away, they are part of an operation, and part of the plan of the overall invasion would be the idea that the ships be resupplied with Drop Tanks. So I am not proposing to just send in ships willy nilly. The military has extraction plans for their troops. Such a plan would have to be developed for these ships.

It comes down to a design philosophy of if you want a Battelrider, OR do you want a fleet of ships that can go in any direction because they are all Jump capable. I just think it is an interesting concept to play around with. It may cost more but allow more flexibility.

The cargo side of things is obvious and profitable, especially with the 2nd edition trade pricing. This may be where the best use of the technology is used. Nice, safe and simple. The logistical overhead is there, but with the income generated I think it will be profitable overall.

 

[AndrewW]

I'm not aware of the partial streamlining and fuel skimming being covered by any rule. Can either of you point me to that?

There's this:

Fuel scoops allow an unstreamlined ship to gather unrefined fuel from a gas giant (streamlined ships have fuel scoops built in automatically).

And:

Partial streamlining allows a ship to skim gas giants and enter atmospheres 3 or below only.

(Or "skin" in the case of the errata)

 

[Chas]

Core Rule Book pg. 143

Partial streamlining allows a ship to skim gas giants and
enter Atmosphere codes of 3 or less, acting in the same
way as streamlined ships. In other atmospheres, the
ship will be ponderous and unresponsive, reliant on its
thrusters to keep it aloft. All Pilot checks will be made
with DM-2.

 

[phavoc]

I'm not aware of the partial streamlining and fuel skimming being covered by any rule. Can either of you point me to that?

There's this:

Fuel scoops allow an unstreamlined ship to gather unrefined fuel from a gas giant (streamlined ships have fuel scoops built in automatically).

And:

Partial streamlining allows a ship to skim gas giants and enter atmospheres 3 or below only.

(Or "skin" in the case of the errata)

I was referring to where in the rules it says you can skim with drop tanks attached. I'm not aware of anywhere in the rules that makes drop tanks essentially part of the ship. They are drop tanks. Fuel skimming is supposed to be a routine, but still dangerous operation. I'm not reading as much versatility into drop tanks as everyone else here.

 

[AnotherDilbert]

A ship using drop tanks cannot be streamlined – at best, it will be partially streamlined.