In the close-up shot of George Owden leaning on the stone parapet and watching the Teasel being towed underneath the bridge, a gray car is shown crossing on the bridge-bed behind him. But then in the immediately-following wide-angle view of the bridge and Owden still looking down at the river, the same car is shown to be just then approaching his position in the middle of the bridge, not yet having passed him.
In the footage of the Margoletta passing under the swing-bridge, there is obviously plenty of clearance above the boat, and so there should have been no need for the bridge's operator to even open the bridge to begin with. And indeed, the yacht's pilot is apparently so impatient to continue on his way that he passes underneath the bridge before it even has a chance to turn the whole way to open the channel; the idea of this scene may be that the hot-headedly impulsive pilot was now a bit extra-wary about passing underneath ANY of the bridges on the river, after already having damaged the Margoletta the day before by attempting to cruise underneath a low bridge at high tide, and so he'd instinctively wanted to "play it safe" by asking the operator to open the bridge, anyway, even though it looked perfectly safe to just pass underneath --- since the pilot had previously underestimated the clearance of that other bridge the day before, however, he may have been reluctant to trust his own judgement on this occasion. Perhaps it could be surmised, though, that one or more of the other equally-reckless members of the "Hullabaloos" had hotly expressed impatience at the delay while the bridge was being operated, and so the pilot had decided to ignore his initial doubts and proceed forward underneath the bridge, even though he'd come to grief from doing so before.
The Margoletta is supposed to be sinking, yet in the wide-angle shot of the rear of the boat, it's obviously high and dry on the river-bottom, with nearly all of the hull exposed, and therefore even more up out of the water than when the boat was floating normally.