Background needed for this to make sense:
https://docs.google.com/document/d/1Qla9L50gw5xyK1QdBkkqm6DpmZ7lsUTqdOfZug6o76M/edit#heading=h.qhigqlraijd5

Following the Imperial Assinatation in 1116, a rapid courier got the
word of the Emperor's death and attendant chaos to the Vargrs near the
Deneb border before the X-boat network's indirect route got it to the
people of Carmel. A group of Vargr corsairs realized the information
advantage and staged a large raid-in-force on several border worlds,
including Carmel.

Baronet Carmel was not pleased.

He decided to set up his own private courier service between Regina
and Carmel, at the best speed he could arrange, J5. There were issues
- the design they came up with for a high speed courier used drop
tanks, and there needed to be way stations where refuelling could
happen.
That process wouldn't be a big deal: hiding a swarm in the Oort cloud
of those systems would be discrete, and nobody would notice. The
problem was delivering the drones.

There was also a desire to be able to deliver large numbers of Brick
and Shingle class drones to the battlefield, and Carmel was a binary
system where the easiest/quickest way to go from one system to another
was a microjump.

This lead to the Umbra class: "The enemy will fight in our shade" , a
reference to what happens when 40 Bricks begin lobbing 3 missiles per
round at a victim.

The Umbra is 300 tons. A 200 ton ovoid with a 100 ton "tail", like a
long silver tadpole. The tail is studded with 70 grapples for
attaching drones, pods, or other things.

Power plant K/mod, M-Drive K/mod, and J-Drive K/Ult give an unloaded
performance of 6G. The J-drive is limited to J-2 due to tech-level
reasons (It's a highly refined version of the TL10 J-drive. On the
plus side it's very small, uses only 70% of the normal amount of fuel,
and is highly reliable. On the minus side, it uses TL10 jump physics,
and can't do better than J2)

It has an internal tank for 79 tons of fuel, supporting J1 and 1
month. For J2 it attaches 3 Fuelbags, each with 23.33 tons of fuel and
uses them as external tanks. Fuel scoops, fuel purifiers and a high
speed pump for draining fuel from drones is provided.

There is a 20 ton bridge, with 10 consoles each having an electronic
brain for independent operation. Adjacent to the bridge is a model
5/mod computer.

There are 10 standard cabins, life support for 1200 person days.

There is a hardpoint with an extended range commcaster, allowing the
ship to act as a communications node and use multiple drones as
'virtual batteries' . This system relies heavily on one-time-pads that
are physically loaded into each drone while docked. Communications
which are not authenticated with the pad are ignored. (In later years,
this proved to be a very effective defense against hacking, even when
dealing with Virus)

The two other hardpoints were split into 3 firmpoints each,  Three
firmpoints were used as 1 ton internal ordinance bays, carrying 50
size-5 missiles each The other three firmpoints mounted quad R5 beam
lasers for missile defense.

Other defenses included a TL12/mod nuclear damper, and an experimental
TL14 black globe generator This early globe did not have the "always
on" option, and did not cycle fast enough for 'flicker' . Instead, it
would come on when the computer detected a threat and remain on for a
few tenths of a second before switching to the next capacitor bank and
resetting. The only mode it operates in is the T5 "roll to intercept"
mode, rolling d6 vs the difference in TL between the attack and the
defense (14). A 1 always succeeds, a 6 always fails. Against TL10
Vargr, this worked 66% of the time. Against a peer (TL14+) it only
stopped an attack 16% of the time.

The wartime loadout was:  35 Bricks, 5 icepicks,3 mints, 20 Shingles,
4 QH's, 3 fuelbag . In Wartime, the expectation was that if they were
picketing a system (ie, part of the quarantine fleet) they would send
5 Bricks, 3 icepicks, 3 mints, 4QHs to the nearest asteroid belt, oort
cloud, planetary ring or whatever resource was handy and set up to
build replacement missiles and drones.  This was also supposed to be a
waystation for the Baronet's couriers.

It could still make J-1 with 1600 tons of subcraft. While there
weren't enough grapples for 160 ten ton drones, this did allow loading
Gunslinger (100 ton) and Rifleman (300 ton) class SDBs for transport.

Trying this as an HTML table to see if it's readable in email..
<table> <thead> <tr> <th>Item</th> <th>Tons</th> <th>Mcr</th> </tr>
</thead> <tbody> <tr> <td>TL 14 "Umbra" - "they will fight in our
shade"</td> <td></td> <td></td> </tr> <tr> <td>Streamlined hull, 300
tons, long tail for grapples</td> <td>-736.5</td> <td>194.4 Mcr</td>
</tr> <tr> <td>Mdrive K/mod 2G @ spec 1000 tons, 1G up to 2000 tons...
6G when clean</td> <td>9.5</td> <td>9.5 Mcr</td> </tr> <tr> <td>Power
Plant K Mod</td> <td>15.5</td> <td>7.75 Mcr</td> </tr> <tr>
<td>Fuel</td> <td>one month</td> <td>9 Mcr</td> </tr> <tr>
<td>Model/0bis/mod + electronic brain x 5</td> <td>1.25</td> <td>1
Mcr</td> </tr> <tr> <td>Jump K/Ult: J2 at spec but need to trade
drones for fuel. J2 max due to TL. J1 out to 2000 tons</td>
<td>13.75</td> <td>41.25 Mcr</td> </tr> <tr> <td>Fuel, J1 full
load</td> <td>70</td> <td>Mcr</td> </tr> <tr> <td>Fuel scoops</td>
<td>1</td> <td>1 Mcr</td> </tr> <tr> <td>Fuel purifier</td> <td>1</td>
<td>1 Mcr</td> </tr> <tr> <td>Fuel pump</td> <td>1</td> <td>1 Mcr</td>
</tr> <tr> <td>70 Grapples for drones</td> <td>70</td> <td>70 Mcr</td>
</tr> <tr> <td>Bridge (consoles)</td> <td>20</td> <td>10 Mcr</td>
</tr> <tr> <td>Computer/5/mod</td> <td>2.5</td> <td>13.5 Mcr</td>
</tr> <tr> <td>Cabins for 10</td> <td>20</td> <td>0.4 Mcr</td> </tr>
<tr> <td>Fresher for 10</td> <td>1</td> <td>1 Mcr</td> </tr> <tr>
<td>Life support: 1200 person days</td> <td>2</td> <td>2 Mcr</td>
</tr> <tr> <td>Commons</td> <td>10</td> <td>0 Mcr</td> </tr> <tr>
<td>Cargo</td> <td>5</td> <td>0 Mcr</td> </tr> <tr> <td>2 hardpoints
to Firmpoints, just shy of 1 ton each (lasers and missile racks)</td>
<td>6</td> <td>3 Mcr</td> </tr> <tr> <td>1 hardpoint -> Commcaster/mod
barbette (virtual batteries using Bricks)</td> <td>3</td> <td>6.5
Mcr</td> </tr> <tr> <td>Bolt in: Early reduced range (R5) Black
Globe-13, overall mod 2</td> <td>1</td> <td>21 Mcr</td> </tr> <tr>
<td>Bolt in nuclear damper-12+Mod, R5: Mod:+5</td> <td>1</td> <td>1.5
Mcr</td> </tr> </tbody> </table>