Ayisha
Contributor
...Watch the perfect trim demonstrations on YouTube. The fins are always moving a little bit. Those guys have their gear dialed in and have lots of practice, but if held perfectly still, they would slowly tilt or rotate...
Not anyone who is worth watching. Any fin movement should be just to maintain position in current or surge.
If they tilt or rotate when perfectly still, they are off balance from head to toe.
When someone is correcting trim with their fins, instead of being flat, their fins will often be pointing up or down.
Rolling, rocking, tilting or pointed fins are dead giveaways for being off-balance.
One of the first things you usually do in a DIR course is to stretch out and hover without making any corrections and let whatever happens happen. If you start rotating, you know you're not balanced from head to toe or side to side. You can then adjust the position of ballast (bp height, tank height, weight placement, etc. or adjust body position (stretch out more, hands in front, hands closer or further apart, legs closer or further apart, knees in line with chest, adjust angle of lower leg bending, etc).
When they hover in static trim, many people who thought they were leg heavy (when swimming diagonally) find out they're head heavy and were overcompensating to see in front of them. If not corrected, it gets amplified when task loaded.
That little static trim exercise is very useful, maybe even for some demonstrators in videos.