Do you have any information on electrically-powered drone boats? Or information that they are electrically powered at all? Evidence I'm finding is that they'r e based on combustion motors.
I'm going to assume that those are low-speed at best. Water transport is efficient at scale, but has tremendous drag, and electric boats (of a non-nuclear sort) will tend to be quite slow.
WWII-era diesel-electric submarines typically have a top speed of less than 10 knots submerged on battery power, as compared with 20 kt surfaced (or at snorkel depth), and in excess of 25 kt for nuclear powered submarines.
Though on writing this I'm noting that the Swedish Gotland-class submarine reports 20 kt submerged on batteries, though only 5 kt on air-independent propulsion (AIP), a Stirling-cycle engine design.
I'm finding very little on UA drone ships / unmanned surface vehicles (USV), but this CNN report shows a still photo of one generating a considerable wake, which I'd estimate shows at least a 15-20 kt speed and possibly greater. The copy reads "faster than anything on the Black Sea". I still suspect that stealth and battery limitations would make lower-speed operations far more common, particularly where the hull could hide from radar or other detection in wave chop.
The accompanying video seems to indicate engine noise, which would indicate combustion-based propulsion. Given that the explosive payload is 300 kg of explosive, and in the Kerch Bridge attack, 1 tonne of high explosive (HE), as well as the extended range of the missions (Odessa to the Sea of Azov), I'd expect that any battery capacity would be limited at best. Fuel, on the other hand, would help enhance explosions and seems far more likely.
I'm going to assume that those are low-speed at best. Water transport is efficient at scale, but has tremendous drag, and electric boats (of a non-nuclear sort) will tend to be quite slow.
WWII-era diesel-electric submarines typically have a top speed of less than 10 knots submerged on battery power, as compared with 20 kt surfaced (or at snorkel depth), and in excess of 25 kt for nuclear powered submarines.
Though on writing this I'm noting that the Swedish Gotland-class submarine reports 20 kt submerged on batteries, though only 5 kt on air-independent propulsion (AIP), a Stirling-cycle engine design.
I'm finding very little on UA drone ships / unmanned surface vehicles (USV), but this CNN report shows a still photo of one generating a considerable wake, which I'd estimate shows at least a 15-20 kt speed and possibly greater. The copy reads "faster than anything on the Black Sea". I still suspect that stealth and battery limitations would make lower-speed operations far more common, particularly where the hull could hide from radar or other detection in wave chop.
<https://www.cnn.com/2023/07/30/europe/ukraine-drones-black-s...>
The accompanying video seems to indicate engine noise, which would indicate combustion-based propulsion. Given that the explosive payload is 300 kg of explosive, and in the Kerch Bridge attack, 1 tonne of high explosive (HE), as well as the extended range of the missions (Odessa to the Sea of Azov), I'd expect that any battery capacity would be limited at best. Fuel, on the other hand, would help enhance explosions and seems far more likely.
<https://yewtu.be/watch?v=Iv1WbNY-yB0>
<https://yewtu.be/watch?v=u7STLTtOEOM>
Ukraine seems to call these "Sea Baby".
<https://www.newsweek.com/ukraine-sea-baby-naval-drones-usv-k...>
Very clear piston motor noises here, I'd estimate 25--50 HP or greater motor:
<https://old.reddit.com/r/NonCredibleDefense/comments/15sp244...>
(25 HP on a light planing hull will give you a pretty impressive top speed, anything above that is gravy.)
This schematic suggests water-jet engines based on a Sea-Doo:
<https://news.usni.org/2022/10/11/suspected-ukrainian-explosi...>
A typical Sea-Doo jetski has a 1600 cc engine of roughly 80 HP / 60 kW.
<https://www.personalwatercraft.com/specs/sea-doo/3-4-passeng...>
<https://www.motorbimble.com/guides/convert-displacement-to-h...>
(Multiple in-place edits as I've turned up more information here.)