The composite yawl Lethe was designed by G.L. Watson and built in the Southampton yard of J.G. Fay & Co. in 1889. Registered at 163 tons gross (114 net), she measured 99 feet in length with a 20 foot beam and was originally owned by Mr. Sidney Watson of Upper Brook Street, London. Subsequently owned by Watson's wife who kept her for relaxation until about 1900, she then passed into the ownership of Lt. Colonel Watson-Kennedy who kept her until 1910 after which she disappears from record.
Lethe was named for the underworld river, the waters of which were said to induce forgetfulness.