All Warships Should Have Drop Tanks

[far-trader]

Where are you placing your deepspace refueling sites? Am I correct that your saying one parsec from the target system?

At the most, possibly closer, possibly even as close as your outer system depending on your patrol resources and lead time for my invasion and other variables.

Reasonable intel? If it takes me one week to jump to the refueling site, and one week to jump to the target system wouldn't that make my intel two weeks old? And If my scout's information is one week old (minimum) when I reach the refueling site wouldn't that make three weeks?

Nope, we have our older Scout data as you outline it of course, but what I was talking about was long range passive looks from the nearby refueling cache to update that. For 1 week old (time to jump in) plus light time lag (a few hours) to the close cache. Ahh, and now I see our major difference in the next bit, which will cause our presumptions to clash. I don't do jump flash. Detection is not so instant and automatic in MTU. We are in different TUs

(...plus I really don't like drop tanks as presented )

 

[Sanjuro]

I can see the virtue in having all ships equipped to allow them to use drop tanks; if the tonnage involved is small, the extra flexibility justifies the cost. However, tankers that can refuel ships after they charge their jump capacitors, but before they jump, would achieve the same end, and in a much more usable form. Is there any rules or canon example of this?

 

[Selandia]

Jump Tanker

I did not find any examples of it in canon, but I am using it anyways under the name of L-Hyd tanker or Jump tanker.

It just make sense. It refills main tankage at the same speed as fuel is burned to load the capacitors. Result: empty jump tanker and full tanks. The tankers drop, to go refill and to be used in later departures. The jumper either burns its remaining fuel or save it for a later jump. In fact, L-Hyd make it possible to have a jumper wo jump fuel tankage

I suppose that the idea never made it in the canon because most works are written for ACS rather than BCS. The jump tankers, a space ship, usually capable of gaz giant skimming, cost a lot more than L-Hyd tanks, but it is worth it if you are playing with a network of bases and supplies lines, or in MTU a liner service (space ships -including tanker- from A to jump tug, jump -tanker drop and return to A-, in-jump, release spaceships that goes to B, 12-24 hours window to pick spaceships -including tanker- from B, jump and it goes all over again.) instead of carrying empty fuel tanks, I carry paying cargo. If I have to pay L-Hyd tanks every trip, with shipyard time to fit them (including the travel to yard time) it is not worth it. Of course, it is not playing trillion credits squadron but rather Trillion credit business... (the players are operating the ships, they are not involved in the backgroung Adventure in Accurate Accounting )

Selandia

 

[aramis]

I can see the virtue in having all ships equipped to allow them to use drop tanks; if the tonnage involved is small, the extra flexibility justifies the cost. However, tankers that can refuel ships after they charge their jump capacitors, but before they jump, would achieve the same end, and in a much more usable form. Is there any rules or canon example of this?

No, it's not doable in canon.

you've maybe got a few minutes, definitely less than 20, to suck the fuel out for jump. Presuming multiple fueling ports, large bore, and backfilling while drawing the main fuel off, it's pretty tight...

With a tanker, if it's larger than you, you're in it's 100 diameter limit, or close to it, and have to disconnect and clear the connections (rather than simply ejecting tanks) before you can get to that point. And if not clear, you go "BOOM!"

The dropped tanks are reusable... or so it appears... but probably shouldn't be given the pseudo-physics Marc has established for jump-entry.

 

[HG_B]

You could always store your fuel in a much more compact form than L-Hyd.

 

[far-trader]

You could always store your fuel in a much more compact form than L-Hyd.

Not without rewriting whole sections of the rules and re-doing every single ship though.

I always treat such ideas as "If that's the best there is, then that's obviously what is being used."

So rather than change everything from Xtons of LH to whatever more compact storage solution presents, I just say it still takes Xtons of the new breakthrough storage solution, and always has. Everything stays the same, no fuss no muss.

 

[HG_B]

Not without rewriting whole sections of the rules and re-doing every single ship though.

Really? The rules prevent the use of chemistry? The rules state H2O is refined into H and then stored.

Can you give the page # where it talks about no chemistry allowed?

 

[far-trader]

Really? The rules prevent the use of chemistry? The rules state H2O is refined into H and then stored.

Can you give the page # where it talks about no chemistry allowed?

No Mr. Science, it does not work that way. You show me where the rules say you can use anything other than the stated Xtons of LH fuel tankage for jump before we entertain those options. You're the one here claiming it can be done. Come on, quote me book and page numbers. I'm waiting....

The rules are pretty vague on just how H2O is "refined" into LH. What it is crystal clear on is that you need Xtons of LH fuel tankage to jump. Period. No fancy chemistry shortcuts like "Oh, we'll store it as water and convert as needed and have several times as much LH in the same space." and other such.

 

[rancke]

I always treat such ideas as "If that's the best there is, then that's obviously what is being used."

Or rather the other way around: "If that's what is being used, then that's obviously the best way there is."


Hans

 

[far-trader]

Or rather the other way around: "If that's what is being used, then that's obviously the best way there is."


Hans

Yep, that works too

 

[HG_B]

No Mr. Science, it does not work that way. You show me where the rules say you can use anything other than the stated Xtons of LH fuel tankage

What is CLEAR Mr. Literate, is that it takes X tons of H fuel to jump. The Jump drive doesn't process "tankage" into power. :rofl:

 

[rancke]

What is CLEAR Mr. Literate, is that it takes X tons of H fuel to jump. The Jump drive doesn't process "tankage" into power. :rofl:

It is also clear that all the hydrogen has to be in pure form, not locked up in water, ammonia or any other compound. You can store it as water, but you'd need sufficient empty tankage to pump the hydrogen into as the water is processed and you'd need to get the processing done in too short a time to be practical for the application you suggest.


Hans

 

[HG_B]

You can store it as water, but you'd need sufficient empty tankage to pump the hydrogen into as the water is processed
Hans

Obviously. How do you think you skim water and then fly off and process it? Interesting indeed!

 

[far-trader]

Obviously. How do you think you skim water and then fly off and process it? Interesting indeed!

Obviously you process it INTO the tankage and end up with the required Xtons of fuel. You don't fill your tankage with water and then process it later.

 

[Theophilus]

Excellent discussion, but please refrain from "snipping".

Okay, lets look at some published (canon) references.

CT Book 5, High Guard, Page 27:

"Disposable fuel tanks may be added to the ship to increase its range. These L-Hyd Tanks are fitted to the outside of the ship of the ship, and drop away before jump, The result is more interior space available for cargo and passengers. Such tanks must be replaced each time they are used, so they are practical only on runs to civilized areas, or to increase fuel capacity to allow several jumps. L-Hyd tanks are installed outside the hull, and increase the total tonnage of the ship. With tanks retained, effeciency is decreased, and jump capability is reduced: when tanks drop away, tonnage is reduced, and the drive effeciency is increased. L-Hyd tanks cost Cr10,000, plus Cr1,000 per ton of fuel carried."

Comments: More interior space for cargo and passengers seem to me to indicate that the drop tank is the only fuel tank. Fine for dedicated merchants, not to for warships.

Or to increase fuel capacity to allow several jumps: What I am proposing.

As to cost: A 10-kton tank would cost Mcr10.01

As to interfering with jump due to the 100d limit: Not referenced here, canon or speculation?

Effect on ship design: None mentioned, no hull space or cost increase to ship, thus fitting the ship for drop tanks is "free".

 

[Theophilus]

TNE, Fusion Fire and Steel Pg 62:

"Ships may be fitted with drop tanks if desired. A drop tank is an additional hull section filled entirely with fuel. Its material volume and mass are calculated just as if it were a seperate ship, and it must use the same hull form and configuration modifiers as the ship it will be fitted to, and must be armored and have internal bracing sufficient to withstand the ship's rated acceleration.
If a drop tank is fitted to a ship with electromagnetic masking, (EMM), the tank(s) must also be so fitted, with the volume and surface area taken out of the tank itself. Power requirements are assumed to be met by the carrying ship, which must allow for them in it's own design. If any EMM-fitted ship is carrying non-EMM drop tanks, the ship looses all EMM benefits until the tanks are dropped.
A drop tank is designed to be released once it is drained, allowing improved performance by the ship."

Comments: Under these rules I would require the carrying ship to treat drop tanks as I would a Rider, that is, an external grapple, and hull shadowing for the drop tank.


Now having these past two posts as a guide, let us continue.

 

[robject]

Enjoying the discussion

I'm enjoying this very much, guys, thank you. And I'm taking notes too.

 

[boomslang]

Comments: More interior space for cargo and passengers seem to me to indicate that the drop tank is the only fuel tank. Fine for dedicated merchants, not to for warships

There is room at this point for academic debate; this is a plausible interpretation -- especially in light of the subsequent mention that drop tanks "must" be replaced each time they are used, yet the archetypical canonical CT example of drop tanks is the (para)military Gazelle class which can function happily without them if necessary. (And gets its allowed hardpoints wrong, but that is a known problem not germane to this analysis, and as below, rules evolution is the prime suspect in an observable discrepancy.)

I suspect the need-for-replacement discrepancy results (like many things originating in CT) from the concept evolving between the time it was first introduced into the rules and its later applications.

 

[far-trader]

More interior space for cargo and passengers seem to me to indicate that the drop tank is the only fuel tank.

I think you have to take it all in context as a whole, specifically:

CT Book 5, High Guard, Page 27:

"Disposable fuel tanks may be added to the ship to increase its range.

...the result is more interior space available for cargo and passengers."

Implies to me that one must have the some range capability on board. If you look at the only(?) canon example that fits:

The Gazelle can make J2 with it's internal tanks of 60tons. The Drop Tanks increase its range and result in more interior space available, in this case for drives and weapons (more on that in a tic*). The Drop Tanks provide for +100tons (J4 retained) or +90tons (J5 dropped) with the internal tankage making up 40% of the required fuel for jump. I've generally used this as the requirement for adding Drop Tanks in MTU. And IIRC T20 did something similar, though I think they used 20% (or J1 worth?). That seemed quite reasonable to me too. The point being the Drop Tanks don't connect directly to the Jump Drive fuel feed, but through the ship's fuel tanks. Using the ship's fuel pumps.

* The only way I figure Drop Tanks may work is if the hull is actually calculated to account for them from the start, both for cost of the hull to accommodate them and the bridge to permit handling. This covers allowing them through Jumpspace (when retained) and maneuvering with them at speed and suited to the config of the ship. My early attempt at reconciling them, prior to and similar to the FF&S rules. What this means among other things is, the Gazelle is not broken with 4 hardpoints. It is a 400ton hull with 100tons of Drop Tanks that can be ditched. You get to keep the hardpoints. What this means is military (generally) ships can (appear to) exceed the 1 hardpoint per 100ton rule. But, see the EDIT followup below...

As to interfering with jump due to the 100d limit: Not referenced here, canon or speculation?

Canon, I'm pretty sure, but can't recall where atm. MT maybe? Somewhere there is a misjump roll DM for using Drop Tanks. That implies that you can't clear the 100D of the tanks before the jump, meaning it has to happen pdq after sucking down the fuel. Pretty sure I didn't just make it up

Another effect I don't recall noted yet (contradicted/changed by FF&S) is that Drop Tanks are not armoured, and can't be, and are extremely vulnerable to damage in combat per HG. Not that anyone would enter combat with them attached

(...hmm, I had other thoughts whizzing around but I type too slowly, they'll come to me again I expect.)

EDIT: I recall one of those thoughts now. TCS threw a wrench into my reasoning above for the way hulls and drop tanks should be handled by stating clearly that drop tank tonnage does not count towards hardpoints. Stupid TCS

 

[aramis]

Canon, I'm pretty sure, but can't recall where atm. MT maybe?

T5. ISTR also in T4 FF&S.

Somewhere there is a misjump roll DM for using Drop Tanks. That implies that you can't clear the 100D of the tanks before the jump, meaning it has to happen pdq after sucking down the fuel. Pretty sure I didn't just make it up

I recall that, too, but not where. Wait... I found it (see below).


Mongoose adds machinery to the cost of drop tanks...

A drop tank mount costs MCr1 per 50 tons of fuel in the drop tank, and takes up two tons of space per 50 tons of fuel for the fittings to transfer fuel.

A drop tank itself costs MCr 0.1 per 50 tons of fuel space.

Jumping using a drop tank applies a –(15–TL) DM to the roll for
misjumping (see page 141 in the core rulebook).

When a drop tank is used, roll 2d6. On an 8+, the tank survives the
ejection process and can be retrieved and reused. Otherwise, it is
destroyed by the expanding jump bubble or warped by the jettison
explosion. At TL14 the use of drop tanks has been improved to such
a degree that drop tanks designed at this tech level or above will
automatically survive use.
(MGT-HG p.43-44)​

Note that the mounting goes on the ship.