Two Men in a Boat (to say nothing of the fog), a remix of A Beautiful Pea-Green Boat by ariadnes_string. Author anonymous until the reveal.
The story stands alone as a work of humor and danger and charm, though as this bird is larded with references to Jerome K. Jerome's comic masterwork, diners familiar with that work will revel in its extra juicy flavor.*
In the course of this voyage, Watson proclaims "I, myself, am never queer at sea." Sherlock, amusingly, is.
*You will also learn many fun facts in the fields of Victoriana, sailing, smuggling, commercial fishing in the North Sea, and drain holes, checking on.