If the 'NjordVessel' object shows a 'Missing Prefab' error when opening the new scene, delete the old vessel from the 'Hierarchy' tab on the left hand side, and drag in the new model found in the NjordVessel folder in the bottom menu.
Note: Ensure that the vessel object (in the Hierarchy tab) is named 'NjordVessel', not 'NjordVessel(1)'. The force controller is configured to correspond with the asset's name.