Here are the videos on Youtube, where one can use < and > to go back and forward frame by frame.
It seems to me that, after the explosion, the color changes yellow to red, emanating from the location of the wake (at 0:16).
Definitely a truck bomb. I’d like to see the footage from the cameras facing the other way for the minute or two before the blast. The truck was driving a straight line at a steady speed, which could point to remote control or set and forget. Let’s see if anybody exited the truck a few hundred meters back.
My guess is a civilian boat, or inflatable craft smuggled from north, which was made remote-controlled A-Team-style, filled with explosive, and then launched from the coast of the Sea of Azov as a kamikaze drone boat directed towards one of the pillars of the road bridge.
I hope that’s not prophetic.
I’m not so sure it was a truck bomb. It looks 2 spans of road were driven up and off the support pillar. The road bed appears to be 1 section but folded in the middle…
Look at the video in Walken_After_Midnight’s post 9329 at 50 seconds into it. The girders that make up sections of the road span 2 sections worth of supports. In other words, if you had 13 supports there would be 6 sections of road bed instead of 12 smaller sections of road bed.
This bit of frame scrubbing agrees with you: there is a flash that precedes the blast that makes it very much look like not a truck bomb.
From Wall Street Journal article:
If it was a boat bomb, why blow road instead of the rail? Extra height makes it unlikely to be effective? Targeting error?
I was just thinking, if divers were used, surely they would have planted explosives on the rail bridge as well.
Maybe the pillars on the road bridge present a larger target?
https://pbs.twimg.com/card_img/1578652555147624449/St2qOqU7?format=jpg&name=900x900
The time delay between the transmitting camera and the person detonating it may have been the difference between hitting the rail bridge and hitting the outermost road. If that’s the case they should tow a 2nd boat behind the first.
Also, the rail bridge is much higher and the shock wave may not carry that far which would require a much large explosion and therefore a ship that the Russians would track and prevent from going under the bridge.
On a side note, I see that Liverpool is going to host Eurovision on behalf of Ukr. I am sure that this corner of England will be turned into a Ukrainian City for the duration and it will be one huge party.
nevermind
That frame scrub seems to show a flash above the bridge, not below it. But I agree, it precedes the blast, and the truck is still visible in the frame.
What I first noticed was the amount of sparks within the billowing clouds. I don’t know anything about explosives but I wonder if thermite was part of the mixture used. It’s not your usual flare up and subsequent cloud from an explosion.
Thermobaric warhead, perhaps. That might explain the initial flash at altitude.
That gets back to my earlier question. The portion of the road bridge that was taken out seems to be much closer to the water than the rail bridge. Maybe that was the best spot for the explosives, if the bomb was under the road bridge?
Aerial view:
It doesn’t look like a truck bomb to me. The condition of the roadbed (other than being in the water 
) is pretty intact. I would think a truck bomb would have blasted big pieces out of out of it, or at least chewed up and scorched the road bed. It looks to me like an explosion cut supports underneath the roadbed and it just fell into the water.
As for why the train bridge was left standing - it could simply be that because it’s much higher off the water, a boat-based explosion could not take it down. To do that you’d have to destroy the actual pillars, which might not have been feasible. But the roadbed was much closer to the water, and an explosion could have wrecked the supporting structure underneath it.
Remote control boats are trivial. I’m pretty sure I could build one that could do the job if I had a few thousand bucks for the task. If Russia lacked radar coverage or patrol capability near the bridge, running an electric boat loaded with explosives under it might have been a lot easier and less risky than trying to get a truck bomb built and hope it could make it onto the bridge without being inspected.
Yeah, that’s the kind of thing I would expect. There are hobbyists who build RC boats that large. That boat could be built by a small group of engineers/craftsmen in no time at all. Off the shelf motors, actuators, boat hull, and Starlink. You could use hobbyist-level RC gear, even simple Wi-Fi based receivers fed by Starlink. It doesn’t even need to be autonomous. With cameras, someone could simply pilotbthat boat right underbthe bridge and detonate it when they wanted.
Look at ll the hobby-level drones being used lethally in Ukraine. One of the groups that caused havoc in the early stages of the war was essentially a bunch of drone hobbyists who volunteered to make war drones in 2014, and kept it up. Boats are even easier than flying craft.