Black Douglas (later teQuest, Aquarius, Aquarius W; now El Boughaz I) is a three-masted staysail auxiliary schooner built for Robert C. Roebling (great-grandson of John A. Roebling and grand-nephew of Washington Roebling) at the Bath Iron Works of Bath, Maine, and launched on 9 June 1930.

The ship undertook a variety of functions during her first three and a half decades: private yacht for the Roebling family, patrol vessel in United States Navy service during World War II (as a "patrol yacht – coastal"; PYc-45), and research vessel for the United States Fish and Wildlife Service plying the Pacific from Alaska to Baja California.

[1] She was bought at auction by Louis Black of Santa Monica, California, to be used as a treasure hunter in the Caribbean.

Black sailed the ship through the Panama Canal and then spent eight years treasure hunting in the Turks and Caicos.

The school closed in 1981 and she was sold, and in 1982–1983 was reconditioned at the Abeking & Rasmussen shipyard in Lemwerder, Germany, serving as a template for the first generation of super yachts.