Abstract: Whale Tank Virtual Reality (VR) is a novel head-coupled VR technique for collocated collaboration. It allows multiple users to observe a 3D scene from the correct perspective through their own personal viewport into the virtual scene and to interact with the scene on a large touch screen display. There are two primary benefits to Whale Tank VR: 1) Head coupling allows a user to experience the sense of a third dimension and to observe difficult-to-see objects without requiring navigation beyond natural head movement. 2) Multiple viewports enable collocated collaboration by seamlessly adjusting the head-coupled perspectives in each viewport according to the proximity of collaborators to ensure a consistent display at all times. One potential disadvantage that we had to consider was that head-coupling might reduce awareness of a collocated coworker's actions in the 3D scene. We therefore conducted an experiment to study the influence of head coupling on users' awareness-and-recall of actions in a simulated collaborative situation for several levels of task difficulty. Results revealed no statistically significant difference in awareness-and-recall performance with or without the presence of head coupling. This suggests that in situations where head coupling is employed, there is no degradation in users' awareness of collocated activity.