The Collaborative International Dictionary
ringsail
Ringtail \Ring"tail`\, n.
(Zo["o]l.) A bird having a distinct band of color across the tail, as the hen harrier.
-
(Naut.) A light sail set abaft and beyong the leech of a boom-and-gaff sail; -- called also ringsail.
Ringtail boom (Naut.), a spar which is rigged on a boom for setting a ringtail.
Wiktionary
ringsail
n. (context nautical English) A light sail set abaft and beyond the leech of a boom-and-gaff sail.