I have seen an upright keel just outside the mooring field while snorkelling on my way to the reef. I don't recall if the keel had a big wing on the bottom. But I supppose it must have.

Warren S/V Scuba Doo
Lagoon 50 (winner of best crewed yacht under 55 feet at the St. Thomas crewed yacht boat show).

https://www.cyabrochure.com/ebn/2307/pdyrX/6642/4///