Awesome job!! What is the cargo tonnage and expected price? Thanks!
Thank you so much for the compliment! And I'm very sorry I'm only getting around to your message now, I hope my answer is not too late to be useful.
Though I'm afraid it might not turn out terribly useful in general, since I can't give a precise answer to the first part of your question - and I'm not entirely sure what you mean with the second part 😅
But let's start with the first: It's really difficult to say what the cargo capacity of La Sirena might be, given that we've never seen her cargo bay. Nor even a proper sketch of what her cargo bay might have been intended to look like. The closest we get is this cutaway from the "Set Me Up" featurette:
On the left-hand side of the cutaway, you can see what is likely supposed to be a cargo bay at the bottom, leading to the big cargo doors. But technically, the space above that is the engine room, and given all the slightly arbitrary geometry in there, I'm not sure any of these spaces in the model were fully thought out by the production team or should be used to draw conclusions about the in-universe ship.
And even taking this model at face-value, it's still really difficult to evaluate the size of the cargo bay. The set of the front part of Sirena, as it was designed and built, is too large to fit into this model. You'd have to make a bunch of adjustments to either the size of the ship or the size of the interiors, and that would have more or less drastic impacts on how large the cargo bay would turn out to be in comparison.
Also, it's very much a question of how the ship is loaded. In an early design phase, all the open spaces along both decks of the ship were supposed to hold modular cargo containers.
Quoting from the Eaglemoss Official Starships Collection Special Issue on La Sirena:
[Art Director Rob] Johnson gave the interior an exposed framework that modular rooms were designed to fit into. The cargo would have done the same job, with different-shaped containers made to fit in the voids in the bulkheads. The cargo was never added and Johnson says what you see is “a skeleton without the organs.”
This is an early design of what this modular cargo might have looked like, also from the booklet.
When we meet Rios and La Sirena in season 1, the only cargo we see are a number of crates strewn around the upper and lower decks.
It stands to reason he wouldn't have too much freight on board, since he has just been hired to ferry Picard to destinations unknown, which doesn't really combine well with any scheduled cargo run. But whether there are these sort of modular containers somewhere in-universe that might be fitted in between the ribs of the ship is never answered.
Apart from storage space inside the ship, though, there is also the fact that Sirena was conceptualized as a tug. Some of the assembly at her back serves as a tether for cargo modules that can be strung together like the cars of a freight train.
At that point, the cargo tonnage of the ship expands dramatically and becomes a question of engine power and warp mechanics that nobody can answer in any meaningful way.
So, the answer to "how much cargo can Sirena transport?" is "almost impossible to answer"it's pretty much impossible to say". Depending on how much you want to bring production design intentions into it, the available space varies between "as many of the sorts of crates we see used in the show stacked along the two decks we know exist for certain" and "that plus some unseen cargo bay" and "densely stacked modular cargo containers designed to slot into all parts of the ship alongside the living quarters and holodeck, plus the same in cargo bay, and a train of freight modules hitched to the back of the ship."
As for the "price": I'm afraid I'm not entirely sure what you're asking here. How much this sort of ship would cost to acquire? How much you would be charged to have your cargo hauled by one of these freighters? What we think Picard might have paid Rios to take him on his little adventure? Something else entirely?
Money is always tricky in Star Trek, but the core of the United Federation of Planets is supposed to be a moneyless, post-scarcity society. If we go by the strictest interpretation, if Rios found Sirena on Earth, he wouldn't have had to pay anything for her. Same goes for shipping costs. If a Kaplan F-17 freighter were operated legally anywhere within or near the core of the Federation, I assume you wouldn't have to pay to acquire their services.
Now, once we move into the further reaches of Federation space, where people do still use money for the exchange of goods and services, things get even more complicated.
According to the designers' original intent, the Kaplan F-17 is fairly old. It was suggested that Sirena was built anywhere between 50 and 100 years before the start of season 1 (which is set in 2399). Acquiring such an old-fashioned ship might not have incurred a huge cost. Then again, she has souped-up engines and weapons, which either Rios or some previous owner added (same with the modular cabins, holodeck, transporter, etc. inside), and which might all affect the price.
And if we're talking about shipping costs, Rios, of course, is operating outside the typical post-capitalism norms of the Federation (and outside Federation space often enough to know e.g. the political situation in and around Vashti fairly well). But it's unclear whether he'd be paid in gold-pressed latinum or some other currency, and the value of any of those are pretty much impossible to know, anyway.
I think in beta canon, i.e. Rogue Elements by John Jackson Miller, we also don't get an exact number for what Rios pays for Sirena, though the down-payment is made in gold-pressed Latinum, and it takes him months to work off the rest of the price. But it's been a while since I've read the book, so I can't give you any more details on that off the top of my head.
Perhaps I might be able to give you some better suggestions about price and cargo if you let me know in a bit more detail what you want to know and what you need it for? (i.e. just out of general curiosity, or for story-writing purposes, or to size a 3D model properly, or....)
I hope I understood your question correctly, and I'm sorry if this answer isn't particularly satisfying 😅 If you're looking for info for a specific reason or project (just out of curiosity, for story-writing purposes, to size a 3D model of the ship more accurately, ...), maybe I might be able to offer more insights or at least point you to some other places that might be able to help?
EIther way, I hope that this was at least a somewhat informative read, and thank you for giving me the opportunity to write about this bit of design history!
