External cargo mounts?

[Annatar Giftbringer]

Greetings,
I have a question about external cargo mounts. Perhaps a silly one, and it’s possible I’m just being daft, but do external cargo mounts always affect total tonnage with regards to thrust and jump rating, or only when filled?

Say we design a ship identical to a standard type S scout, but we add a 100 dt external cargo mount to the hull before finalizing the design.

Would this ship always count as thrust 1 jump 1, or would it be thrust 2 jump 2 as long as the external mount is empty?

 

[AnotherDilbert]

I assume only actually carried cargo affects drive performance:

A ship’s Thrust and jump capability must be recalculated when using external cargo mounts, using the combined tonnage of the ship and the external cargo it carries.

So a Scout-like ship with external cargo mounts, but no external cargo, would be J-2 & M-2.

 

[Annatar Giftbringer]

I’m thinking there’s two ways to interpret that. It could mean that when a ship design uses the optional external cargo mount its tonnage needs to be recalculated, meaning that while the hull might be 100 dt the total ship always counts as 200 dt for the sake of, well basically everything. The benefits would include using a smaller Hull to haul more cargo, meaning the ship is cheaper (hull size, bridge, crew requirements and so on).

Or, it could mean that the current cargo load on the external mount decides what tonnag the ship currently counts as, for the sake of jump and thrust. This would mean that our modified scout from before behaves like a regular scout ship when unloaded but when the external mount is filled it gets recalculated to thrust & jump 1. 50 dt external cargo would mean thrust 1,5.

The second option would make for a very flexible ship, able to function as a fast, long range courier or heavy cargo hauler depending on current need. This could be useful for free traders for example, allowing the crew to travel far an wide in search of good trade, and when a suitable cluster is found, haul cargo and earn money. Long range courier and sub merchant in one hull!

 

[Condottiere]

The issue is the calculation of volume.

If the external mount was within a thin metal shell that remained attached to the hull, arguably that would be considered volume that needed to be accounted, with or without cargo.

The frame itself doesn't have measurable volume, so it's petty much just the cargo that's relevant.

 

[Anonymous]

Otherwise you're going you need to install doors in it.

 

[AnotherDilbert]

The second option would make for a very flexible ship, able to function as a fast, long range courier or heavy cargo hauler depending on current need.

Quite, but this is not really for Free Traders. Since external cargo must be loaded in orbit (or on an airless moon), it is not suitable for the marginal worlds Free Traders frequent, as they probably don't have all that much orbital infrastructure.

But on the main trade routes it allows a ship to carry as much cargo as possible for the jump range required.

 

[Reynard]

These mounts seem a little vague. Unlike a docking clamp which had tonnage itself, the ECM is only a cost for a certain cargo tonnage it will accommodate and has explosive ejection bolts to release said cargo. The 'framework' takes up no volume. The cargo enclosure must be thin enough to not be significant compared to the cargo itself and the cargo and it's enclosure are treated as a single unit that is attached to said frame. It's only when containers are attached they add displacement to the ship.

I picture the Han Solo incident when he had to dump the cargo akin to a cargo freighter pursued by hostile forces and is forced to jettison ECM pods to up its maneuver and possibly jump to escape.

 

[Anonymous]

Aircraft underwing cargo pods? They might have ejection as they go on the bomb rails.

Cargo ships have been known to lighten their load in emergency (look up "general average"). Containers on a freighter can be powered by the ship's generators (needed for refridgerated containers) which is hard to do under Traveller rules if they're external pods. (In Mongoose, they might need to be built with small craft hulls and held on a docking clamp).

 

[Condottiere]

Until I looked it up, I hadn't realized it just cost a thousand per tonne in schmuckers, and nothing in additional volume or penalizes acceleration beyond an accounting for that additional volume.

Tsk, tsk, tsk ...

 

[Reynard]

"A ship using external cargo mounts will become unstreamlined."

So there is some effect.

 

[Anonymous]

And no maximum volume limit - and unless I'm misreading the rules, it's also protected by the armor?

 

[AnotherDilbert]

And no maximum volume limit - ...

Implicitly there is a limit: You have to have a drive performance of 1 or higher, otherwise the ships in effect becomes a station.

At some point the external cargo will risk interfering with the jump bubble; I tend to use Jump Nets to make sure the jump bubble is extended. It also keeps it from being essentially free.

... - and unless I'm misreading the rules, it's also protected by the armor?

Quite, there are no special rules for damage to external load, such as drop tanks, external cargo, or clamped craft. It keeps things simple...

If we want to complicate things we could house-rule that you have a proportional chance to hit the external component instead of the ship? E.g. a 100 Dton ship with 100 Dt external cargo has a 50% chance of the cargo being hit instead of the ship.

 

[Anonymous]

 

[Reynard]

The point of external cargo is it is not within the protection of the hull.Objects such as externally carried craft are subject to being hit if targeted. Small craft would defend using their own armor and absorb damage to their hulls. Unprotected pods and drop tanks have no armor and should use the drop tank rule being destroyed when the ship takes 10% hull damage and even auto destroyed if targeted.

 

[AnotherDilbert]

Agreed, that would be simpler and avoid the concept of using external cargo as a damage buffer.

 

[Condottiere]

1. Streamlining only matters within an atmosphere.

2. A balanced load will matter within a gravity field and during acceleration.

3. Dead slow, clear skies, and gravity lifters should allow an unstreamlined spaceship to land on a planet fairly in tact.

 

[PsiTraveller]

If the Jump drive is big enough to move the ship into Jump space the lack of M-Drive capacity may not be an issue. The ship could be a transfer point designed to move as much cargo to the next system as possible. It may have to be loaded at the Jump point by tenders once the tonnage exceeds M-Drive capacity. It depends on the intent of the ship.

As for the idea of using the external mounts as cheap armour. Just have the ship take damage AND lose the cargo.

 

[Condottiere]

You can divide infinitely and move at a thousandth of a gravity.

 

[Old School]

Cargo carried externally isn’t going to last very long in combat if I’m the referee. It’s also not going to provide any meaningful protection.

(“But but but. . .those “common industrial parts” we’re carrying externally are really bonded superdense plates! So we’re going to keep that side of the ship facing the enemy so we’ll have Armor 50!”)

 

[Anonymous]

Cargo carried externally isn’t going to last very long in combat if I’m the referee. It’s also not going to provide any meaningful protection.

(“But but but. . .those “common industrial parts” we’re carrying externally are really bonded superdense plates! So we’re going to keep that side of the ship facing the enemy so we’ll have Armor 50!”)

MS Yaramar, Drinax registration. 600 tons jump-2. Drinax to Torpol with a cargo of sandcaster crystals. Don't worry, the boxes will probably fall of the ship if you shoot it hard enough. Probably. Use missiles to shake it up a bit. Or use a laser and aim REALLY well.