Walt Whitman - poem about Cmdr. William B. Cushing, USN

I came across a passing reference to Whitman having written a poem about this celebrated Civil War naval hero, who sank the Confederate ironclad CSS Albemarle in a daring nighttime raid in October 1864. Melville also wrote a poem about him, and I have that (“At the Cannon’s Mouth”), but I haven’t been able to find Whitman’s poem anywhere; I don’t even know its title.

Anyone know it?