learn-scuba once bubbled...
In the real world, it is folly to assume students are going to be neutral, off the bottom and properly trimmed. They have far more to worry about than where their fins are. I never have figured out why open water freaks them out like it does -- water is water, right? -- but it does. No matter how much time you spend practicing skills, buoyancy and trim in the pool, they always seem to forget the instant they hit the open water. A student who sank like a rock in the pool is floating like a cork in open water because they're stressed.