Answer:
A caribbean shape that makes ships disappear.
To cross the water, I'm the way. For water I'm above, I touch it not and truth to say, I neither swim nor move. What am I?
You use me between your head and your toes the more I work the thinner I grow.
My first is high my second damp my whole a tie a writer's cramp.
My days are numbered.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.