Drop tank mounted fuel/cargo tanks

[mavikfelna]

Ok, I had an idea.
On a standard Type-S you can add external fuel mounts for .4 tons and 200Kcr for the ability to mount 100 tons of tanks. This does not affect your streamlining unless a tank is actually attached. This allows a Type-S to make 6 jump-1s, giving is substantial legs for the rare time it might need it.

So, what if you mounted fuel/cargo containers in the tank instead of pure fuel tanks? Make the tanks give up 5% of their capacity and cost an additional 5Kcr and now you have a 95-ton container that can carry fuel or cargo. Now, the cargo would be treated as being external, with no gravity or atmosphere support but it would at least be protected from vacuum by a sealed tank. There is also no power to the tank. This makes a nice alternative to a Type-A free trader that a scout could pick up.

The tank in this case would be 30Kcr per ton, or 3Mcr, but since you're reusing it, it's not a lost cost. Developing a trade route, where you have a factor that loads up a tank for you would mean you could jump in, roll up to the high port and drop the tank you have, move over and install the new tank and be off in a matter of hours.

And, if you need that last 5 tons of fuel for some reason, add a 5 ton collapsable fuel bladder in the cargo hold.

I haven't looked at the economics of this yet, I'm just fleshing out the idea. But a scout courier configured this way should be comparable to a 200t cargo trader with J-1 M-1 engines. And any time they want to drop their tanks and store them somewhere, there are alot of scout bases out there.

The rules for drop tanks do have an Engineering Jump DM penalty equal to 15 - the TL of the tanks. I would assume a default of TL12 for drop tanks that are not Imperial Navy, as that is typically the TL default for Type-S and Type-A ships. So there is a penalty for using these. But there is no penalty to the cost for building them at a higher TL. So if you have access to an appropriate fab or yard, you'll pay the same at TL15 as TL12.

 

[rinku]

I can't see much of an issue here, but I'd go with external fuel/cargo pods, not drop tanks as such, since the internal fuel IS sufficient to make one J-1, and them being pure drop tanks can't improve the jump performance (you just detach them and revert to jump 2). Transfer fuel from external cargo to top up the internal tanks (probably less than an hour's operation) and make the next J-1.

Might be worth considering twin 50 ton mounts, defaulting to one cargo and one fuel. Or some other combo.

The drop tank option - actually dropping whatever tanks are installed - would allow the Scout to make a J-2 while arriving ready to make a second J-2. So that's not a dumb setup... but there would be no point in having drop tanks that weren't 10 or 20 tons.

 

[Fluffy Bunny Feet]

Go with a breakaway 2nd hull for cargo. Primary hull has the fuel and passengers. Drop off the 2nd hull and passengers, reload passengers and pickup a copy of the 2nd hull and make the return flight with minimal turn over. Jump drive is in use most of the time and you make nearly twice as many runs/month. Whole outfit is streamlined and the 2nd hull is only in space while connected to the prime hull, doesn't need J-Drive, M-Drive or bridge. Should give you a unique Free Trader with over 90 tons of cargo.

 

[rinku]

Ugh. Just realised that external cargo mounts aren't available to streamlined hulls.
Since this is an existing ship, not a new design, breakaway hulls are probably off the table too. And docking clamps are going to need more spare tonnage than a Scout really has to spare.

You MIGHT be able to make it work with an Interstellar Jump Net, since those only use up 1 ton for up to 100tons of cargo. Install that on a scout and carry fuel and cargo containers as you see fit. MCr10 for 100 ton capacity one, but totally flexible.

 

[mavikfelna]

Ugh. Just realised that external cargo mounts aren't available to streamlined hulls.
Since this is an existing ship, not a new design, breakaway hulls are probably off the table too. And docking clamps are going to need more spare tonnage than a Scout really has to spare.

You MIGHT be able to make it work with an Interstellar Jump Net, since those only use up 1 ton for up to 100tons of cargo. Install that on a scout and carry fuel and cargo containers as you see fit. MCr10 for 100 ton capacity one, but totally flexible.

That is a doable option. More expensive but it's more fully inline with the current rules. Still, can cargo in a jump net transfer fuel? Would you need both the cargo net and the external fuel mounts?

 

[Condottiere]

It's an old conceptual option.

Tends to pale, once you get others.

The weakness being easily damaged, and cost.

 

[rinku]

That is a doable option. More expensive but it's more fully inline with the current rules. Still, can cargo in a jump net transfer fuel? Would you need both the cargo net and the external fuel mounts?

No, I think transferring fuel or cargo from a jump net into the ship would be a space suit (or robot/drone) job. Not a particularly difficult one, mind you. It's likely doable with a purpose built hose and careful cargo placement. Safety concerns might prevent leaving the hose in place while jumping.

 

[rinku]

Back to external cargo frames - they can't be used on streamlined ships (presumably the frames themselves permanently make the ship unstreamlined, even with no cargo) or dispersed structure (dispersed ships presumably have their cargo mounted that way normally...), and the trick is only going to work on J-2 or higher ships, or they'll need bigger drives.

So of the standard ships, that leaves... the Subsidised Liner, the Corsair and the Mercenary Cruiser. (Yacht is J-1, Scout and Safari ship are streamlined, Free, Far and Fat Traders are both. Lab Ship is dispersed).

I could definitely see a Corsair crew bolting on some external cargo to either extend their fuel or their treasure chest. They often run away by jumping in-system. A Liner might also want to tailor itself to a J-2 route by adding fuel or cargo. +80 tons of fuel gives the ship a 2xJ-2, which could be handy for bridging rifts, or running a service where one end doesn't have refueling capabilities.

 

[phavoc]

Ugh. Just realised that external cargo mounts aren't available to streamlined hulls.
Since this is an existing ship, not a new design, breakaway hulls are probably off the table too. And docking clamps are going to need more spare tonnage than a Scout really has to spare.

You MIGHT be able to make it work with an Interstellar Jump Net, since those only use up 1 ton for up to 100tons of cargo. Install that on a scout and carry fuel and cargo containers as you see fit. MCr10 for 100 ton capacity one, but totally flexible.

This is one of those places where reality and the game rules diverge. It used to be that Traveller-ideas were mirrored in the real world. However, as technology concepts have changed the game did not change with them. There is a concept called conformal fuel tanks that aircraft such as the F-15 and F-16 have. These are mounted so that the aircraft can carry extra fuel but not use up any external ordnance carry points. The downside is that they can't be dropped either, as they are more or less permanently attached to the aircraft for in-flight ops (and directly plumbed into the aircraft fuel system).

Starships are similar to aircraft analogues, but not 100%, so some things may be possible and others not so much. However aircraft ARE streamlined, thus the idea should be adaptable to starships and still allow them to retain their streamlining characteristics. Where I can see issues is that by adding bulk to the hull you could cover up sensors, hatches, restrict firing arcs (though Traveller doesn't actually have them even when a ship has turrets). The bigger problem is how would you get the game to reflect the reality that things don't come without costs and consequences as they do in reality?

 

[Vormaerin]

The more detailed versions of ship design (like Fire, Fusion, and Steel) did use surface area of the hull as a restriction on all manner of things that are currently handwaved for simplicity. This is one of those questions that can't really be answered in the plug & play version of ship design.

It's the same with firing arcs. Traveller pays lip service to firing arcs in its descriptions, but the game itself operates at a level of abstraction where facing, relative position, and other vectors are not calculated (just raw distance), so in effect turrets are always 360. But that isn't literally true.

 

[rinku]

This is one of those places where reality and the game rules diverge. It used to be that Traveller-ideas were mirrored in the real world. However, as technology concepts have changed the game did not change with them. There is a concept called conformal fuel tanks that aircraft such as the F-15 and F-16 have. These are mounted so that the aircraft can carry extra fuel but not use up any external ordnance carry points. The downside is that they can't be dropped either, as they are more or less permanently attached to the aircraft for in-flight ops (and directly plumbed into the aircraft fuel system).

Starships are similar to aircraft analogues, but not 100%, so some things may be possible and others not so much. However aircraft ARE streamlined, thus the idea should be adaptable to starships and still allow them to retain their streamlining characteristics. Where I can see issues is that by adding bulk to the hull you could cover up sensors, hatches, restrict firing arcs (though Traveller doesn't actually have them even when a ship has turrets). The bigger problem is how would you get the game to reflect the reality that things don't come without costs and consequences as they do in reality?

Well, no. It just means that the equipment being described isn't that. It seems to be large boxy structures bolted onto the hull. Cheap, and totally ruins the streamlining. No aircraft would ever have such a thing, though watercraft might.

If you want streamlined external cargo, that would be a new thing.

 

[phavoc]

Well, no. It just means that the equipment being described isn't that. It seems to be large boxy structures bolted onto the hull. Cheap, and totally ruins the streamlining. No aircraft would ever have such a thing, though watercraft might.

If you want streamlined external cargo, that would be a new thing.

Well, when Traveller was first proposed you had very large computers. That's been changed since more power microelectronics came into being and showed that it was possible. The idea of conformal fuel tanks didn't exist at that time, so large tanks (boxy or external streamlined on hard points) were the norm. Revising the rules based on changes is as canon in Traveller as the 4 hardpoint, 300 Dton escort ship!

It doesn't seem like an issue to have something similar for ships. Though with anti-grav, a ship of just about any configuration is able to enter an atmosphere and land (if carefully), which renders the need for streamlining moot for many activities.

 

[rinku]

Although External Cargo Mounts will make semi-streamlined ships Unstreamlined. And even if landing on a vacuum world they require a difficult landing roll or they might damage the external cargo.

 

[Condottiere]

In theory, you could tinker with drop tank configuration.

Also, external cargo mounts.

 

[mavikfelna]

In theory, you could tinker with drop tank configuration.

Also, external cargo mounts.

I wanted to avoid External Cargo Mounts to avoid making the ship itself unstreamlined. Otherwise that would have been my choice. If there was some sort of option for retractable external mounts that didn't affect streamlining when not in use, that would work too. And if you added the option to install a fuel line plumbing connection, so the external cargo could be used for drop tanks, even better.

 

[Terry Mixon]

I wanted to avoid External Cargo Mounts to avoid making the ship itself unstreamlined. Otherwise that would have been my choice. If there was some sort of option for retractable external mounts that didn't affect streamlining when not in use, that would work too. And if you added the option to install a fuel line plumbing connection, so the external cargo could be used for drop tanks, even better.

Maybe attach the external cargo mounts via docking clamps? Remove them when not in use?

 

[MasterGwydion]

Maybe attach the external cargo mounts via docking clamps? Remove them when not in use?

Double the cost and tonnage of the docking clamp and make it a pop-up docking clamp.

 

[Terry Mixon]

Double the cost and tonnage of the docking clamp and make it a pop-up docking clamp.

There you go. If it works for weapons, do it for external cargo mounts.

 

[Condottiere]

You should take into consideration how much stress the pop up element of the docking clamp can take.

 

[MasterGwydion]

You should take into consideration how much stress the pop up element of the docking clamp can take.

Why? Think how the bolts work on a safe door. Do the same thing with the pop-up part. It pops up and locks into position on all sides. Now it is directly bolted, immobile, to the hull.

Edit - Plus, you doubled the cost and the tonnage. It's already been taken into consideration.