If Ukraine can get some in there, my guess is that it's plausible that they put all of them in that way. Less risky if they can do it from a range standpoint, as long as they then have the range left to go where they want in the Sea of Azov.

Does that mean that they have a 1000 km range? I dunno. I mean, Ukraine can launch the things from other places on the Black Sea, maybe.

My understanding is that the propulsion works like a jet-ski.

https://luxuryviewer.com/which-jet-ski-has-the-longest-range/

Jet skis aren’t typically measured by their range capabilities, as it’s a massively hypothetical area. However, the Sea-Doo SPARK 60 HP reportedly takes the crown. Its tiny engine is extremely fuel-efficient, and estimates suggest it could cover 166 miles with a single tank of gas.

https://sea-doo.brp.com/content/dam/global/en/sea-doo/my24/documents/specs-sheets/na/en/SEA-MY24-REC-SPA-SPEC-ENNA-Page-PDFx.pdf

That's on 7.9 gallons of fuel, and that's 267 km.

The Sea Baby is hauling an 850 kg warhead, but it's also not hauling a person, which mitigates some of that.

I don't see size data for it, and most shots don't have stuff for scale, but here's one with a human and a Magura 5 (not a Sea Baby).

https://media.cnn.com/api/v1/images/stellar/prod/230729120919-01-ukraine-sea-drones.jpg?c=16x9&q=w_800,c_fill

That thing is a lot bigger than a jet-ski. I'd guess that it's at least 10 feet long. Like, I don't think that you'd have trouble fitting 32 gallons of fuel in there. CNN cites that model as having an 800 km range.

And the Magura 5 is considerably smaller:

Unlike the Sea Baby used by the SBU, which carries a heavier explosive payload and is primarily used to strike stationary targets such as ships docked in port, the MAGURA V5 is designed for striking warships at sea due to its smaller size and better manoeuvrability.[1]

https://en.wikipedia.org/wiki/MAGURA_V5

According to the WP data, the Magura 5 can do 800 km and weighs something like what the Sea Baby warhead weighs.

So I don't think that it's implausible that the Sea Baby could do over 1000 km.