How to spell STYUNSAIL correctly?

If you're trying to spell "staysail", you might have better luck! A staysail is a type of sail that's attached to a stay or a wire or rope that helps support the mast. Other possible suggestions for "styunsail" could include "stunsail" (a type of extra sail used in fair weather) or "spinnaker" (a large, balloon-like sail that's used for downwind sailing).