It was Rani Arbo who wrote the music to that poem. She has recorded it on her album "Bottleneck Dreams" with her old band, Salamander Crossing. If you don't know her, she's a neo-traddie and sometime songwriter who plays very fine fiddle, and lives in CT.
Notes in the album: "Crossing the Bar, Poem by Alfred Lord Tennyson, Music by Rani Arbo (Jinn Mill Music/BMI, 1998). Dedicated to Elizabeth E May, with apologies to her and to Mr Tennyson for swapping around the verses."

My singing partner and I do Crossing the Bar, scooping it up immediately after hearing Rani do it in May 2003 in Peterborough, NH. She told a lovely story about it which is something like what follows.
Either her or her husband's grandmother (can't recall which) came to the States from a non-Anglo country. Gran learned a good deal of her English from books, and was fond of a high literary style. Upon her deathbed, where Rani was in attendance, the grandmother (fairly out of it, and close to the end) whispered a poetic line, which Rani did not know. They wrote down what they thought she was saying, to see what it was she was trying to tell them. But she wasn't telling them anything. She was probably somewhere back in her youth, in her head, because she quoted a line from a Tennyson poem, and it turned out to be Crossing the Bar. That was the inspiration for Rani to turn the poem into a song.