I was cleaning up old sig quote files which caused me to look for a
current link to this classic example of Vilani engineering.

The TL A Orrimot Logistic Ship

https://www.dedzone.net/traveller/BARD/sara/sara5018.html

The intro:

Every starfleet needs a vast number of these unglamourous ships -
although you never seem to see them in "Imperial Stars", "Strike Fleet",
or any of the other popular VR entertainment programs in the Imperium.
Never mind that: without thousands and thousands of glorified cargo
barges like these, the Imperial Navy would swiftly grind to a halt.

First built in 138, these flying bricks perfectly reflect the big, bulky
and dour design philosophy of the Vilani. They also happen to be quite
capable in their work: after all, 1000 years later they still serve in
innumerable frontier fleets, as tankers and second-tier naval logstics
vessels.

(In a pinch they can support Marine contigments, but lack the armour to
serve in any more hostile environment than your typical bushfire
rebellion. They also lack sufficent on-board cargo shuttles, and the
Marines get to sleep in the cargo hold - hopefully modified to house
them, rather than sleeping on the bare floor.

The Orrimot DOES at least have CG lifters, unlike most dedicated space
tankers/freighters. So it can lift off, as well as land...)

These ships are rarely seen in civilian service: the two large hamster
cages used to mimic gravity is rather unpopular among merchants, and
civilian fuel stations have rendered tanker jumpships a poor economic
gamble. Also, most merchants find the additional cost to maintain the
inefficent dual fusion plants not worth the greater safety margin. And
the 10 lifeboats are SO passe, and an unnecessary expense - although the
crews doesn't seem to mind.

Well, the Orrimot is just the oldest and the most primitive of the vast
(an I mean VAST) array of cargo/refuelers that has been built for the
Imperial Navy over the centuries. "Ugly, stinky, and full of odd
grinding noises" is the usual shorthand description. Cheap, also, for
it's purpose: discounts on the price may hit 80%, since the basic
model's so well known. Even it's base price is quite reasonable for a
tanker of it's type, as it lacks expensive artificial gravity. For the
cash-strapped colonial and planetary navies which need a handy jump-3
tanker/cargo ship, this is the way to go.

I would feel that it's unpopularity would stem from the hard-to-find
part's and supplies it needs, as it was designed before most of the
modern Imperial Naval Part's spec's were set. Fortunately, the Orrimot
spec's are usually ancient ancestors to today's spec's, and the
relationship is close enough so that, even if you can't find exactly
what you're looking for, you can jury-rig something fairly easily.