Continuity mistake: When James has just jumped out of the plane, he has a diving rig that is somewhat different to the one he has when diving on the wreck of the Devonshire. In the water, he wears a twinset manifold air-bottle rig. While skydiving, the rig was not manifolded, and the bottles were in a different position on his back. To change between the two requires some work with a toolkit, preferably on dry land.