Bastian Fan-Boards

A membrane mermaid or mermaid prison suit is not designed for fun.  When the membrane is worn, it practically fuses the legs together and hide the arms.  The gills on the neck draws in and filters air that flows through tubes that go into the mouth and nose, but the amount of airflow is hampered, so the wearer would have to pucker in like a fish.   The fins help the wearer move through the water...



The fins can also be removed, transforming the membrane into an underwater sheath.  The major difference is that the lack of fins make it difficult for the wearer to move underwater and impossible to resurface.  This would make it easier for their captors to retirive them if needed.