We've all seen chase sequences. One of the things that makes them work is recognizable geography. One party in the chase goes past an identifiable landmark and then a shot or two later, the other party passes the same landmark. It's a way for the audience to know who is in front and how much space is between the two parties.
One of the most interesting things about the whale chase is that there is almost no recognizable geography. Until the end, when Pinocchio swims towards a gap in the rocky shoreline, all we've got is water and sky. There are rocks that go by in the foreground to add depth to shots, but these rocks are fairly generic. We're not using them as landmarks to measure the relative positions of the characters.
In a situation like this, screen direction becomes the only tool to communicate location to the audience. It's one of the reasons I'm so impressed with this sequence and the credit goes to sequence director Bill Roberts and layout supervisor Al Zinnen. In the hands of lesser film makers, a chase on the open ocean could be confusing; the audience could easily lose its bearings. Roberts and Zinnen make sure that we always understand where the characters are relative to each other and they do it with screen direction.
As the sequence starts, Pinocchio and Geppetto are pushing their raft screen left, trying to get past Monstro's teeth. Monstro sneezes them out and then on his inhale, begins to pull them back towards screen right. We can easily tell by their direction whether they're getting farther or closer to Monstro.
Monstro then starts to chase them towards screen left and dives below the water. When he rises below the raft in shot 12, he's still heading towards screen left as the raft is lifted and Geppetto and Pinocchio bounce along Monstro's back. This shot always astounds me. For one thing, the use of scale contrasts the fragility of Geppetto and Pinocchio relative to Monstro's bulk. For another, this shot trumps any in John Huston's version of Moby Dick. Here is animation doing something that live action could not duplicate until the advent of cgi.
Geppetto and Pinocchio fall into the water and then there is a clear shot of Monstro turning around and swimming towards screen right. There's no ambiguity here as to where Monstro is going next. Geppetto and Pinocchio climb back on the raft and start to paddle towards screen right. When Monstro catches up with them and looms over them, they reverse direction and paddle screen left. Monstro's tail descends and smashes the raft before he continues under water off screen towards the right.
Pinocchio swims to save Geppetto and Monstro emerges from the water now heading screen left towards the pair. Pinocchio looks screen right and sees Monstro approaching. Then he looks screen left and sees the gap in the rocks at the shoreline. He starts swimming towards screen left, pulling Geppetto behind him, while Monstro pursues.
When Pinocchio has reached the rocks, we get a point of view shot where Monstro is swimming towards the camera. Monstro leaps over some rocks heading screen left. Pinocchio frantically tries to swim into the gap screen left. Monstro leaps towards the camera in shot 39, almost devouring the audience in the most dramatic shot of the sequence.
(And I wonder if there was a debate as to how close to bring Monstro to the camera. After the criticism that Snow White was too scary for young children, did they cut this shot before Monstro's mouth enveloped the camera? My modern sensibility wishes that they'd let Monstro get closer before cutting.)
Monstro then smashes into the rocks going screen left and beyond the rocks, the tide moving screen left washes up Geppetto and then follows by washing up Figaro and Cleo in a terribly unbelievable coincidence. A close examination of the sequence shows that Figaro and Cleo disappear in shot 12 and are definitely not on the raft in shot 15 when Pinocchio and Geppetto climb back on. I've often wondered why there wasn't a shot of Geppetto putting them into the trunk on the raft and have the trunk wash up onto shore. It's not a perfect solution, but better than the one that was chosen.
Forgetting about Figaro and Cleo, there is never a moment where the audience is confused about the relative locations of the characters. That allows the audience to concentrate on the danger and as a result the suspense never lets up. The storytelling here is exquisitely clear in a difficult setting for a chase.