In this video you'll see this Nautlius submarine that was actually designed from the model used in the feature film. As you will see in the video it has 2 clever modifications. First it does not have dive has a propellor that changes pitch. Second as the scale rudder was not effective it was extended with some transparent plastic to give it more authority in the water.

Filmed at the Southern Model Show 2017 in Headcorn, Kent, UK.